Re: [MBZ] OT = On topic 124/OM602 overheating
Hey Larry hope your doing well. I talked with Wilton the other day, he and his wife are doing well. I think Curly finally replaced the t-stat as well as some other stuff, he should update us again. Max Dillon Charleston SC Apr 9, 2020 2:24:11 PM Larry Turner via Mercedes : > Hello All - > Back when I had the car, I replaced the Rad when the upper nozzle broke. At > that time I cleaned between the rad & the condensor so that should still be > clean. > > One thing about the T'Stat - 1st one I bought was right catalog # but it was > too small (or vice versa) so I got the right one and all was well. That > doesn't mean it didn't fail soon after I started using it. I also put a new > Fan Clutch on. But at one point, I had cooling issues and I replaced > everything assoc w/the cooling - at least the front of engine components. > > I also noticed the Aux fans only seemed to run when the AC was on - I thought > that might be the way it was supposed to run. IAC, as Curley found, when AC > is on the Aux fans work and Temp is not a problem. > > Hopefully, by now Curley has found / fixed the problem. > > I hope everyone is staying healthy in these times... > > LarryT > '06 E350 (which may a new the Conductor Plate) > > On 3/14/2020 8:51 AM, Meade Dillon via Mercedes wrote: > > > Curley, I've got three of these cars, '87 with OM603 and two '95's with > > OM606NA. None of them need the aux fan running in the summer heat, unless > > the AC is running or I'm carrying a big load or running fast on the highway > > up hill and then suddenly slow down. > > > > Just driving around town at 75 deg F, with no AC running, the car should > > not need the aux fans running. > > > > I disagree, you've got evidence that the t-stat is failed. They can fail > > right out of the box! > > > > In your place, I would remove the front bumper and the fan shroud and clean > > out the leaves and bugs between shroud and condenser, pull the radiator and > > clean between radiator and condenser, spray your garden hose through both > > while you have it all apart, and then pull the t-stat and check it for > > function. > > > > Here are the specs from MB: > > > > OM601, 602.91, 603.91: begin opening @ 85 +/-2 deg C, minimum stroke 8mm @ > > 94 deg C > > > > If the AC refrigerant has leaked down, then only the high speed function of > > the aux fans will work. > > - > > Max > > Charleston SC > > > > > > On Fri, Mar 13, 2020 at 11:38 PM Curley McLain via Mercedes < > > mercedes@okiebenz.com> wrote: > > > > > > > because the problem is not the thermostat. On this one, the radiator is > > > blocked by a shroud, except for where the 2 fans are. I'm guessing that > > > is to keep bugs out of the radiator. So without the fans running, it > > > runs too hot. when the fans run it is fine. Larry put a new > > > thermostat in it not that long ago. If I had evidence of a thermostat > > > problem I would change it. so far it is quite clear: Fans running, no > > > overheat. Fans not running, overheating. With the sensor on top of > > > the engine plugged in, the fans never run. THat is a problem. When > > > that sensor is unplugged, the fans are intermittent. > > > > > > If the R134a has leaked out, would the low pressure switch cause the > > > fans not to run? Seems to me that the fans should be independent of > > > the a/c, but obviously they are linked at the drier. Fans should run > > > when the A/c is off. > > > > > > > > > > > ___ > > http://www.okiebenz.com > > > > To search list archives http://www.okiebenz.com/archive/ > > > > To Unsubscribe or change delivery options go to: > > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Hello All - Back when I had the car, I replaced the Rad when the upper nozzle broke. At that time I cleaned between the rad & the condensor so that should still be clean. One thing about the T'Stat - 1st one I bought was right catalog # but it was too small (or vice versa) so I got the right one and all was well. That doesn't mean it didn't fail soon after I started using it. I also put a new Fan Clutch on. But at one point, I had cooling issues and I replaced everything assoc w/the cooling - at least the front of engine components. I also noticed the Aux fans only seemed to run when the AC was on - I thought that might be the way it was supposed to run. IAC, as Curley found, when AC is on the Aux fans work and Temp is not a problem. Hopefully, by now Curley has found / fixed the problem. I hope everyone is staying healthy in these times... LarryT '06 E350 (which may a new the Conductor Plate) On 3/14/2020 8:51 AM, Meade Dillon via Mercedes wrote: Curley, I've got three of these cars, '87 with OM603 and two '95's with OM606NA. None of them need the aux fan running in the summer heat, unless the AC is running or I'm carrying a big load or running fast on the highway up hill and then suddenly slow down. Just driving around town at 75 deg F, with no AC running, the car should not need the aux fans running. I disagree, you've got evidence that the t-stat is failed. They can fail right out of the box! In your place, I would remove the front bumper and the fan shroud and clean out the leaves and bugs between shroud and condenser, pull the radiator and clean between radiator and condenser, spray your garden hose through both while you have it all apart, and then pull the t-stat and check it for function. Here are the specs from MB: OM601, 602.91, 603.91: begin opening @ 85 +/-2 deg C, minimum stroke 8mm @ 94 deg C If the AC refrigerant has leaked down, then only the high speed function of the aux fans will work. - Max Charleston SC On Fri, Mar 13, 2020 at 11:38 PM Curley McLain via Mercedes < mercedes@okiebenz.com> wrote: because the problem is not the thermostat. On this one, the radiator is blocked by a shroud, except for where the 2 fans are. I'm guessing that is to keep bugs out of the radiator. So without the fans running, it runs too hot. when the fans run it is fine. Larry put a new thermostat in it not that long ago. If I had evidence of a thermostat problem I would change it. so far it is quite clear: Fans running, no overheat. Fans not running, overheating. With the sensor on top of the engine plugged in, the fans never run. THat is a problem. When that sensor is unplugged, the fans are intermittent. If the R134a has leaked out, would the low pressure switch cause the fans not to run? Seems to me that the fans should be independent of the a/c, but obviously they are linked at the drier. Fans should run when the A/c is off. ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
The 201 chassis is the only place I've seen electric fan clutches on MBs. On Sun, Mar 15, 2020 at 6:54 PM Curt Raymond via Mercedes < mercedes@okiebenz.com> wrote: > Interesting, yours is a 602 NA?Mine were both 601 and both were electric. > -Curt > > On Saturday, March 14, 2020, 4:38:06 PM EDT, Jim Cathey via Mercedes < > mercedes@okiebenz.com> wrote: > > > The 190 had an electric clutch if I remember correctly, while the W124 > has a viscous clutch. > > > W201's vary. Ours (diesel) has a visco-clutch. > > -- Jim > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > -- OK Don "Whenever you find yourself on the side of the majority, it is time to pause and reflect." Mark Twain "There are three kinds of men: The ones that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves." WILL ROGERS, *The Manly Wisdom of Will Rogers* 2013 F150, 18 mpg 2017 Subaru Legacy, 30 mpg 1957 C182A, 12 mpg - but at 150 mph! ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
> Interesting, yours is a 602 NA? > Mine were both 601 and both were electric. Yes. OM602 NA, visco-fan. -- Jim ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Interesting, yours is a 602 NA?Mine were both 601 and both were electric. -Curt On Saturday, March 14, 2020, 4:38:06 PM EDT, Jim Cathey via Mercedes wrote: > The 190 had an electric clutch if I remember correctly, while the W124 has > a viscous clutch. W201's vary. Ours (diesel) has a visco-clutch. -- Jim ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
thanks Dan. Dan Penoff via Mercedes wrote on 3/14/20 5:03 PM: Here’s a BW thread about using a resistor to lower the resistance of the sensor on the block: https://www.benzworld.org/threads/auxillary-fan-turn-on-set-point-resistor-modification.1629476/ It’s kind of convoluted reading, but I seem to recall using a couple of 2.2k ohm resistors in parallel to get my cut in point to about 92C. -D On Mar 14, 2020, at 5:55 PM, Curley McLain via Mercedes wrote: Found relays K9 and K10. pulled them out, and when I put one (k10) in I had low speed! Put the other in and had high speed!(Dryer switch jumped and top sensor unplugged.) With both relays back in , I plugged in the top sensor, and the dryer switch and went for a drive. all ok for a while, Temp stable at 82. Then temp climbing/no fans. Stopped pulled out the top sensor plug. fans running/ temp going back to normal. Came home, pulled the relays. changed the low speed one. everything appears to be working again. Could be a bad relay, bad contact on the pins or bad connection on the pins where the relay plugs in. The 87 has a double top sensor. one 2 pin and one 1pin. resistance, cold between the 2 pins is infinity, compared to 5K ohm on the 91 with a 2 pin sensor. SDL has the same 3 pin sensor. I need to go back and pull the plug off it and check cold resistance. (it was stuck too tight to get it off by hand) Since they are not he same as the 91 OM602, I don't know if their resistance is meaningful for comparison or not. I stole a relay from the SDL and stuck it in the low speed (k10) slot. We will see what happens now. I think the dryer switch may be ok, but no way to test it right now. not sure if the top sensor is right and I don't know what its resistance cold/hot should be. Anyone got information about it? I also did further testing on the viscous clutch. It is low on oil. Had a spare used MB one, but it had leaked oil all over. Not a good sign! Max Dillon via Mercedes wrote on 3/14/20 3:04 PM: I think that low speed fan circuit has a big resistor between the ABS pump and the fender. If that resistor is open circuit, no fan operation. Had that on my '87. Max Dillon Charleston SC Mar 14, 2020 3:42:46 PM Curley McLain via Mercedes : Done that. it has no effect whatsoever. (indicates electrical problem, not mechanical) Craig via Mercedes wrote on 3/14/20 2:30 PM: otherwise, the next fix is to put a manual switch on the fans or wire them to run whenever the key is on. You can do that by shorting the terminals at the receiver/filter/dryer I mentioned in one of my emails. I had to do that on our '90 E300D because the switch on the side of the receiver/filter/driver was bad and removing it would have opened the A/C system. Craig ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Here’s a BW thread about using a resistor to lower the resistance of the sensor on the block: https://www.benzworld.org/threads/auxillary-fan-turn-on-set-point-resistor-modification.1629476/ It’s kind of convoluted reading, but I seem to recall using a couple of 2.2k ohm resistors in parallel to get my cut in point to about 92C. -D > On Mar 14, 2020, at 5:55 PM, Curley McLain via Mercedes > wrote: > > Found relays K9 and K10. pulled them out, and when I put one (k10) in I had > low speed! Put the other in and had high speed!(Dryer switch jumped and > top sensor unplugged.) > > With both relays back in , I plugged in the top sensor, and the dryer switch > and went for a drive. all ok for a while, Temp stable at 82. Then temp > climbing/no fans. Stopped pulled out the top sensor plug. fans running/ > temp going back to normal. > > Came home, pulled the relays. changed the low speed one. everything appears > to be working again. > > Could be a bad relay, bad contact on the pins or bad connection on the pins > where the relay plugs in. > > The 87 has a double top sensor. one 2 pin and one 1pin. resistance, cold > between the 2 pins is infinity, compared to 5K ohm on the 91 with a 2 pin > sensor. SDL has the same 3 pin sensor. I need to go back and pull the plug > off it and check cold resistance. (it was stuck too tight to get it off by > hand) Since they are not he same as the 91 OM602, I don't know if their > resistance is meaningful for comparison or not. > > I stole a relay from the SDL and stuck it in the low speed (k10) slot. > > We will see what happens now. > > I think the dryer switch may be ok, but no way to test it right now. > not sure if the top sensor is right and I don't know what its resistance > cold/hot should be. Anyone got information about it? > > > I also did further testing on the viscous clutch. It is low on oil. Had a > spare used MB one, but it had leaked oil all over. Not a good sign! > > Max Dillon via Mercedes wrote on 3/14/20 3:04 PM: >> I think that low speed fan circuit has a big resistor between the ABS pump >> and the fender. If that resistor is open circuit, no fan operation. Had that >> on my '87. >> >> Max Dillon >> Charleston SC >> >> Mar 14, 2020 3:42:46 PM Curley McLain via Mercedes : >> >>> Done that. it has no effect whatsoever. (indicates electrical problem, not >>> mechanical) >>> >>> Craig via Mercedes wrote on 3/14/20 2:30 PM: >>> > otherwise, the next fix is to put a manual switch on the fans or wire > them to run whenever the key is on. > You can do that by shorting the terminals at the receiver/filter/dryer I mentioned in one of my emails. I had to do that on our '90 E300D because the switch on the side of the receiver/filter/driver was bad and removing it would have opened the A/C system. Craig >>> ___ >>> http://www.okiebenz.com >>> >>> To search list archives http://www.okiebenz.com/archive/ >>> >>> To Unsubscribe or change delivery options go to: >>> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >>> >>> >> >> >> ___ >> http://www.okiebenz.com >> >> To search list archives http://www.okiebenz.com/archive/ >> >> To Unsubscribe or change delivery options go to: >> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >> > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Found relays K9 and K10. pulled them out, and when I put one (k10) in I had low speed! Put the other in and had high speed! (Dryer switch jumped and top sensor unplugged.) With both relays back in , I plugged in the top sensor, and the dryer switch and went for a drive. all ok for a while, Temp stable at 82. Then temp climbing/no fans. Stopped pulled out the top sensor plug. fans running/ temp going back to normal. Came home, pulled the relays. changed the low speed one. everything appears to be working again. Could be a bad relay, bad contact on the pins or bad connection on the pins where the relay plugs in. The 87 has a double top sensor. one 2 pin and one 1pin. resistance, cold between the 2 pins is infinity, compared to 5K ohm on the 91 with a 2 pin sensor. SDL has the same 3 pin sensor. I need to go back and pull the plug off it and check cold resistance. (it was stuck too tight to get it off by hand) Since they are not he same as the 91 OM602, I don't know if their resistance is meaningful for comparison or not. I stole a relay from the SDL and stuck it in the low speed (k10) slot. We will see what happens now. I think the dryer switch may be ok, but no way to test it right now. not sure if the top sensor is right and I don't know what its resistance cold/hot should be. Anyone got information about it? I also did further testing on the viscous clutch. It is low on oil. Had a spare used MB one, but it had leaked oil all over. Not a good sign! Max Dillon via Mercedes wrote on 3/14/20 3:04 PM: I think that low speed fan circuit has a big resistor between the ABS pump and the fender. If that resistor is open circuit, no fan operation. Had that on my '87. Max Dillon Charleston SC Mar 14, 2020 3:42:46 PM Curley McLain via Mercedes : Done that. it has no effect whatsoever. (indicates electrical problem, not mechanical) Craig via Mercedes wrote on 3/14/20 2:30 PM: otherwise, the next fix is to put a manual switch on the fans or wire them to run whenever the key is on. You can do that by shorting the terminals at the receiver/filter/dryer I mentioned in one of my emails. I had to do that on our '90 E300D because the switch on the side of the receiver/filter/driver was bad and removing it would have opened the A/C system. Craig ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Even though this wiring diagram says it is for 93 and later, I think it will work for your car for the aux fan circuits. - Max Charleston SC On Sat, Mar 14, 2020 at 5:24 PM Meade Dillon wrote: > There are two relays: K9, which operates the high speed function of the > aux fans, and K10 which is for the low speed function (low speed circuit > goes through a big resistor to drop the voltage). K9 is in position C in > the fuse box, K10 is position B in the fuse box. > > High speed circuit: Test by jumping the temperature sensor/switch at the > top front of head, makes both fans run in high speed, I think you've > confirmed that this works. > > This information is for an '87 diesel, and also works for a '93 diesel, so > I think it will cover your '91 diesel. > > Low speed circuit: Signaling side of the relay: Fuse 7 to K10 pin 4. K10 > pin 5 goes to S32 (refrigerant pressure switch) which goes to ground. > Powering side of the relay: K10 pin 3 is power from Fuse D. K10 pin 1 goes > to the resister (located by the ABS pump and the reciever/dryer, behind the > left front headlight), then to the fans. > > > Test for power from Fuse 7 to K10 pin 4 with key on. Test for power from > Fuse D to K10 pin 3 with key on. Test if the resistor is open or 0.2 ohms > (correct value is 0.2 ohms). Test that K10 pin 5 has continuity to one of > the connections as the S32 pressure switch, and test that the other > connector has continuity to ground. Test that there is continuity from the > resistor to the motors. > > Order a new t-stat, so that after you get all that straightened out and > the car is still running too hot, you can fix the real problem (I predict) > which is a bad t-stat. > - > Max > Charleston SC > > > > >> 2483500.pdf Description: Adobe PDF document ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
There are two relays: K9, which operates the high speed function of the aux fans, and K10 which is for the low speed function (low speed circuit goes through a big resistor to drop the voltage). K9 is in position C in the fuse box, K10 is position B in the fuse box. High speed circuit: Test by jumping the temperature sensor/switch at the top front of head, makes both fans run in high speed, I think you've confirmed that this works. This information is for an '87 diesel, and also works for a '93 diesel, so I think it will cover your '91 diesel. Low speed circuit: Signaling side of the relay: Fuse 7 to K10 pin 4. K10 pin 5 goes to S32 (refrigerant pressure switch) which goes to ground. Powering side of the relay: K10 pin 3 is power from Fuse D. K10 pin 1 goes to the resister (located by the ABS pump and the reciever/dryer, behind the left front headlight), then to the fans. Test for power from Fuse 7 to K10 pin 4 with key on. Test for power from Fuse D to K10 pin 3 with key on. Test if the resistor is open or 0.2 ohms (correct value is 0.2 ohms). Test that K10 pin 5 has continuity to one of the connections as the S32 pressure switch, and test that the other connector has continuity to ground. Test that there is continuity from the resistor to the motors. Order a new t-stat, so that after you get all that straightened out and the car is still running too hot, you can fix the real problem (I predict) which is a bad t-stat. - Max Charleston SC > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
> The 190 had an electric clutch if I remember correctly, while the W124 has a > viscous clutch. W201's vary. Ours (diesel) has a visco-clutch. -- Jim ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
I think that low speed fan circuit has a big resistor between the ABS pump and the fender. If that resistor is open circuit, no fan operation. Had that on my '87. Max Dillon Charleston SC Mar 14, 2020 3:42:46 PM Curley McLain via Mercedes : > Done that. it has no effect whatsoever. (indicates electrical problem, not > mechanical) > > Craig via Mercedes wrote on 3/14/20 2:30 PM: > > > > > > otherwise, the next fix is to put a manual switch on the fans or wire > > > them to run whenever the key is on. > > > > > You can do that by shorting the terminals at the receiver/filter/dryer I > > mentioned in one of my emails. I had to do that on our '90 E300D because > > the switch on the side of the receiver/filter/driver was bad and removing > > it would have opened the A/C system. > > > > > > Craig > > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Done that. it has no effect whatsoever. (indicates electrical problem, not mechanical) Craig via Mercedes wrote on 3/14/20 2:30 PM: otherwise, the next fix is to put a manual switch on the fans or wire them to run whenever the key is on. You can do that by shorting the terminals at the receiver/filter/dryer I mentioned in one of my emails. I had to do that on our '90 E300D because the switch on the side of the receiver/filter/driver was bad and removing it would have opened the A/C system. Craig ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
On Sat, 14 Mar 2020 13:52:28 -0500 Curley McLain via Mercedes wrote: > I do not see any way to take off/take out the front shroud and fans, > other than removing radiator, condensor etc. Trying to avoid that for > now. For sure, you do not have to remove the condenser. IIRC, you also do not have to remove the radiator. You may have to loosen the mounting clips and tip it backwards with the condenser. > If anyone can find a wiring diagram, that would be very helpful. I already posted them to the List; check your email. > I have been looking at the manual on Dave M's site and on the > w124-zone.com site, I don't find any diagnostic for the fan circuits > other than the 83-544 posted earlier for the dryer switch. > If I could get to it, I'd be tempted to cut out the lower part of the > front shroud to allow airflow other than past the electric fans. But > will run as designed if I can find the problem. No, don't do that! If you cut out the lower portion of the front shroud you will greatly reduce the effect of the auxiliary fans when they are needed. > otherwise, the next fix is to put a manual switch on the fans or wire > them to run whenever the key is on. You can do that by shorting the terminals at the receiver/filter/dryer I mentioned in one of my emails. I had to do that on our '90 E300D because the switch on the side of the receiver/filter/driver was bad and removing it would have opened the A/C system. Craig ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
yep got that. Craig via Mercedes wrote on 3/14/20 12:39 PM: On Fri, 13 Mar 2020 19:26:04 -0500 Curley McLain via Mercedes wrote: I think in some prior discussion I remember that the )M60x has 2 fan switches. Apparently they are in parallel. Anyone know if or where this other switch could be? I sent the schematics with another email. Attached is the picture of the A/C filter dryer/reservoir and its switches. The auxiliary fan switch is the red one with the flying leads which connect with faston terminals to two wires which go off into the wiring harness. Craig ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Ok, here is the latest. Top sensor, 2 pin, at the top of the head, next to 1 pin temp sensor (coolant exit to radiator) 5,000 ohm resistance, cold between the 2 pins Blue/white wire: 5 v brown wire 0 volts Dryer fan switch Infinite resistance cold = open circuit Brown/Blue wire 12v brown wire 0 volts. with key on, fans are running with plug on top sensor disconnected. the dryer fan connectors open or jumped made no difference. Took loose the rear shroud took loose the radiator. Front of radiator/back or condensor are clean. I do not see any way to take off/take out the front shroud and fans, other than removing radiator, condensor etc. Trying to avoid that for now. Because there is 5 v., not 12v. on the blue/brown wire at the top sensor, there has to be some other device in the circuit that is reducing voltage from 12 to 5.Is this the resistor near the dryer? If anyone can find a wiring diagram, that would be very helpful. I have replace many viscous clutches, and refilled 3 or 4 others. This viscous clutch is ok. It looks like it may have been replaced when the radiator was replaced. I have been looking at the manual on Dave M's site and on the w124-zone.com site, I don't find any diagnostic for the fan circuits other than the 83-544 posted earlier for the dryer switch. As for changing antifreeze, that has been planned for months for after everything is working and the shakedown is done. right now, I want to get the electric fan controls fixed before I change the antifreeze, so I am trying to leave the coolant system intact and trying to leave the refrigerant system intact for now. If I could get to it, I'd be tempted to cut out the lower part of the front shroud to allow airflow other than past the electric fans. But will run as designed if I can find the problem. otherwise, the next fix is to put a manual switch on the fans or wire them to run whenever the key is on. ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Correct Sent from my iPhone > On Mar 14, 2020, at 12:17 PM, Peter Frederick via Mercedes > wrote: > > The 190 had an electric clutch if I remember correctly, while the W124 has a > viscous clutch. > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
The 190 had an electric clutch if I remember correctly, while the W124 has a viscous clutch. ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
>Are you sure the fan clutch kicks on at 80? In my 190e 2.6 it is supposed to come on at 100c or 105c, but not 80c. There is a resistor mod you can do at the temp sensor connector that can lower it (assuming they are similarly set up). Dan posted on that years ago when he had the 140 coupe. Rick ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Yes overheating in my 90 300D 2.5t (now Dimitri's) was cured by a new fan clutch. Dwight E. Giles Jr. Wickford RI On Sat, Mar 14, 2020 at 11:39 AM Curt Raymond via Mercedes < mercedes@okiebenz.com> wrote: > If the engine fan is working and its 75F and its overheating you've got > some other problem(s). The aux fans should be unneeded in those conditions. > I agree that a thermostat would be one of my first things to test. The car > has sat awhile no? I'd probably swap the coolant too. > Angie's Golf had a mystery coolant leak only discovered when my TDI guru > used a pressure tester. Perhaps you're loosing pressure somewhere, a > cracked tank maybe? > I drove 2 different 190Ds with bad fan clutches, those use an electric > clutch. In each case the car was fine as long as it didn't have to sit in > heavy traffic. The second car had a working aux fan so it'd just cycle up > to 105F, the fan would come on and bring it down, then it would cycle back > up. The first car I had to be dammed careful in heavy traffic... > -Curt > > On Saturday, March 14, 2020, 1:59:59 AM EDT, Curley McLain via > Mercedes wrote: > > Yes, the belt driven fan is whirring away nicely, otherwise, it would be > dead in the water in about 200 yards. (or suffer an engine meltdown if > you didn't stop) It keeps the temp from getting abouve ~105º C. > > This one is different in that the front of the radiator is blocked by a > front shroud, except for the 2 electric fans. apparently they are > supposed to run at one speed for normal driving and at a higher speed > for running with the air cond. on. When they are stopped, they block > the airflow to the radiator even more. > > That is why I have to find out how to get them to run as they are > supposed to. > > Rick Knoble via Mercedes wrote on 3/14/20 12:25 AM: > > Stupid question. Is the fan clutch working? > > You would be amazed at the difference a working vs. non-working fan > clutch can make. Most folks think that above 30 mph, the fan has no impact, > but I can tell you with first hand experience, that is not true. > > > > Rick > > > > > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Roughly 80C at the fan clutch I think. Might be a bit warmer, but well below "overheat" on the temp gauge. I think I've replaced three over the years. ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
80C at the fan itself though right? I was under the impression that the viscous fan clutch requires itself to get hot to operate. -Curt On Saturday, March 14, 2020, 10:43:59 AM EDT, Kaleb Striplin via Mercedes wrote: Are you sure the fan clutch kicks on at 80? I thought the thermostat didn’t even start opening till 80 or so and was not fully opened till warmer than that. Sent from my iPhone > On Mar 14, 2020, at 9:02 AM, Peter Frederick via Mercedes > wrote: > > The fan clutch kicks in around 80C and should keep you at normal operating > temp unless you have the AC on, in which case as long as there is high > temperature on the high pressure side of the compressor the fans will run at > low speed. > > They should NOT be on in normal driving. > > You have a bad fan clutch -- easy to test. With the engine warm enough for > the clutch to be engaged you should hear it roaring and when the engine is > shut of it should stop within a second or two. On startup cold you should > hear it run for a few seconds as the clutch fluid spins out of the plates. > > If it's not pushing quite a bit of air with a warm engine, it's dead and > needs to be replaced. > > Been there a number of times, probably 90% of your trouble is a dead visco > clutch. > > The rest of it is either a bad ground or a bad electric fan motor or two. > Since they both run it's not the last issue, something stuck in them to > prevent rotation. > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
If the engine fan is working and its 75F and its overheating you've got some other problem(s). The aux fans should be unneeded in those conditions. I agree that a thermostat would be one of my first things to test. The car has sat awhile no? I'd probably swap the coolant too. Angie's Golf had a mystery coolant leak only discovered when my TDI guru used a pressure tester. Perhaps you're loosing pressure somewhere, a cracked tank maybe? I drove 2 different 190Ds with bad fan clutches, those use an electric clutch. In each case the car was fine as long as it didn't have to sit in heavy traffic. The second car had a working aux fan so it'd just cycle up to 105F, the fan would come on and bring it down, then it would cycle back up. The first car I had to be dammed careful in heavy traffic... -Curt On Saturday, March 14, 2020, 1:59:59 AM EDT, Curley McLain via Mercedes wrote: Yes, the belt driven fan is whirring away nicely, otherwise, it would be dead in the water in about 200 yards. (or suffer an engine meltdown if you didn't stop) It keeps the temp from getting abouve ~105º C. This one is different in that the front of the radiator is blocked by a front shroud, except for the 2 electric fans. apparently they are supposed to run at one speed for normal driving and at a higher speed for running with the air cond. on. When they are stopped, they block the airflow to the radiator even more. That is why I have to find out how to get them to run as they are supposed to. Rick Knoble via Mercedes wrote on 3/14/20 12:25 AM: > Stupid question. Is the fan clutch working? > You would be amazed at the difference a working vs. non-working fan clutch > can make. Most folks think that above 30 mph, the fan has no impact, but I > can tell you with first hand experience, that is not true. > > Rick > > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
On that engine, the t-stat starts to open at 85. They run a little hotter than earlier engines. Max Dillon Charleston SC Mar 14, 2020 10:43:59 AM Kaleb Striplin via Mercedes : > Are you sure the fan clutch kicks on at 80? I thought the thermostat didn’t > even start opening till 80 or so and was not fully opened till warmer than > that. > > Sent from my iPhone > > > > On Mar 14, 2020, at 9:02 AM, Peter Frederick via Mercedes > > wrote: > > > > The fan clutch kicks in around 80C and should keep you at normal operating > > temp unless you have the AC on, in which case as long as there is high > > temperature on the high pressure side of the compressor the fans will run > > at low speed. > > > > They should NOT be on in normal driving. > > > > You have a bad fan clutch -- easy to test. With the engine warm enough for > > the clutch to be engaged you should hear it roaring and when the engine is > > shut of it should stop within a second or two. On startup cold you should > > hear it run for a few seconds as the clutch fluid spins out of the plates. > > > > If it's not pushing quite a bit of air with a warm engine, it's dead and > > needs to be replaced. > > > > Been there a number of times, probably 90% of your trouble is a dead visco > > clutch. > > > > The rest of it is either a bad ground or a bad electric fan motor or two. > > Since they both run it's not the last issue, something stuck in them to > > prevent rotation. > > ___ > > http://www.okiebenz.com > > > > To search list archives http://www.okiebenz.com/archive/ > > > > To Unsubscribe or change delivery options go to: > > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > > > > > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Are you sure the fan clutch kicks on at 80? I thought the thermostat didn’t even start opening till 80 or so and was not fully opened till warmer than that. Sent from my iPhone > On Mar 14, 2020, at 9:02 AM, Peter Frederick via Mercedes > wrote: > > The fan clutch kicks in around 80C and should keep you at normal operating > temp unless you have the AC on, in which case as long as there is high > temperature on the high pressure side of the compressor the fans will run at > low speed. > > They should NOT be on in normal driving. > > You have a bad fan clutch -- easy to test. With the engine warm enough for > the clutch to be engaged you should hear it roaring and when the engine is > shut of it should stop within a second or two. On startup cold you should > hear it run for a few seconds as the clutch fluid spins out of the plates. > > If it's not pushing quite a bit of air with a warm engine, it's dead and > needs to be replaced. > > Been there a number of times, probably 90% of your trouble is a dead visco > clutch. > > The rest of it is either a bad ground or a bad electric fan motor or two. > Since they both run it's not the last issue, something stuck in them to > prevent rotation. > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
And aftermarket viscous fan clutches are notoriously poor quality and rarely in spec. I had some success in refilling them, which is pretty simple to do. Over time the oil leaks out and they start acting up. -D > On Mar 14, 2020, at 10:02 AM, Peter Frederick via Mercedes > wrote: > > The fan clutch kicks in around 80C and should keep you at normal operating > temp unless you have the AC on, in which case as long as there is high > temperature on the high pressure side of the compressor the fans will run at > low speed. > > They should NOT be on in normal driving. > > You have a bad fan clutch -- easy to test. With the engine warm enough for > the clutch to be engaged you should hear it roaring and when the engine is > shut of it should stop within a second or two. On startup cold you should > hear it run for a few seconds as the clutch fluid spins out of the plates. > > If it's not pushing quite a bit of air with a warm engine, it's dead and > needs to be replaced. > > Been there a number of times, probably 90% of your trouble is a dead visco > clutch. > > The rest of it is either a bad ground or a bad electric fan motor or two. > Since they both run it's not the last issue, something stuck in them to > prevent rotation. > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
The fan clutch kicks in around 80C and should keep you at normal operating temp unless you have the AC on, in which case as long as there is high temperature on the high pressure side of the compressor the fans will run at low speed. They should NOT be on in normal driving. You have a bad fan clutch -- easy to test. With the engine warm enough for the clutch to be engaged you should hear it roaring and when the engine is shut of it should stop within a second or two. On startup cold you should hear it run for a few seconds as the clutch fluid spins out of the plates. If it's not pushing quite a bit of air with a warm engine, it's dead and needs to be replaced. Been there a number of times, probably 90% of your trouble is a dead visco clutch. The rest of it is either a bad ground or a bad electric fan motor or two. Since they both run it's not the last issue, something stuck in them to prevent rotation. ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Switches are in the hot side line -- receiver/dryer switch wire goes to a resistor located close by, the engine switch wire goes to the 'far' side of the same resistor for full fan speed. If the hot side is hot, you have a bad ground. I'm guessing it's in the same general area as the resistor, but I've personally never looked. ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Curley, I've got three of these cars, '87 with OM603 and two '95's with OM606NA. None of them need the aux fan running in the summer heat, unless the AC is running or I'm carrying a big load or running fast on the highway up hill and then suddenly slow down. Just driving around town at 75 deg F, with no AC running, the car should not need the aux fans running. I disagree, you've got evidence that the t-stat is failed. They can fail right out of the box! In your place, I would remove the front bumper and the fan shroud and clean out the leaves and bugs between shroud and condenser, pull the radiator and clean between radiator and condenser, spray your garden hose through both while you have it all apart, and then pull the t-stat and check it for function. Here are the specs from MB: OM601, 602.91, 603.91: begin opening @ 85 +/-2 deg C, minimum stroke 8mm @ 94 deg C If the AC refrigerant has leaked down, then only the high speed function of the aux fans will work. - Max Charleston SC On Fri, Mar 13, 2020 at 11:38 PM Curley McLain via Mercedes < mercedes@okiebenz.com> wrote: > because the problem is not the thermostat. On this one, the radiator is > blocked by a shroud, except for where the 2 fans are. I'm guessing that > is to keep bugs out of the radiator. So without the fans running, it > runs too hot. when the fans run it is fine. Larry put a new > thermostat in it not that long ago. If I had evidence of a thermostat > problem I would change it. so far it is quite clear: Fans running, no > overheat. Fans not running, overheating. With the sensor on top of > the engine plugged in, the fans never run. THat is a problem. When > that sensor is unplugged, the fans are intermittent. > > If the R134a has leaked out, would the low pressure switch cause the > fans not to run? Seems to me that the fans should be independent of > the a/c, but obviously they are linked at the drier. Fans should run > when the A/c is off. > > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Yes, the belt driven fan is whirring away nicely, otherwise, it would be dead in the water in about 200 yards. (or suffer an engine meltdown if you didn't stop) It keeps the temp from getting abouve ~105º C. This one is different in that the front of the radiator is blocked by a front shroud, except for the 2 electric fans. apparently they are supposed to run at one speed for normal driving and at a higher speed for running with the air cond. on. When they are stopped, they block the airflow to the radiator even more. That is why I have to find out how to get them to run as they are supposed to. Rick Knoble via Mercedes wrote on 3/14/20 12:25 AM: Stupid question. Is the fan clutch working? You would be amazed at the difference a working vs. non-working fan clutch can make. Most folks think that above 30 mph, the fan has no impact, but I can tell you with first hand experience, that is not true. Rick ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Stupid question. Is the fan clutch working? You would be amazed at the difference a working vs. non-working fan clutch can make. Most folks think that above 30 mph, the fan has no impact, but I can tell you with first hand experience, that is not true. Rick ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
because the problem is not the thermostat. On this one, the radiator is blocked by a shroud, except for where the 2 fans are. I'm guessing that is to keep bugs out of the radiator. So without the fans running, it runs too hot. when the fans run it is fine. Larry put a new thermostat in it not that long ago. If I had evidence of a thermostat problem I would change it. so far it is quite clear: Fans running, no overheat. Fans not running, overheating. With the sensor on top of the engine plugged in, the fans never run. THat is a problem. When that sensor is unplugged, the fans are intermittent. If the R134a has leaked out, would the low pressure switch cause the fans not to run? Seems to me that the fans should be independent of the a/c, but obviously they are linked at the drier. Fans should run when the A/c is off. Meade Dillon via Mercedes wrote on 3/13/20 8:22 PM: Why don't you replace the thermostat? If you dig into the FSM for the HVAC system, it will have the test procedures for both low and high cooling fan operation. Section 83 I believe. - Max Charleston SC ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
Re: [MBZ] OT = On topic 124/OM602 overheating
Why don't you replace the thermostat? If you dig into the FSM for the HVAC system, it will have the test procedures for both low and high cooling fan operation. Section 83 I believe. - Max Charleston SC On Fri, Mar 13, 2020 at 8:26 PM Curley McLain via Mercedes < mercedes@okiebenz.com> wrote: > I took off this afternoon with all fans a blazing away, and a nice rock > solid 92º C temp. Great! On the way back from a BP session, I saw > the temp at 105 again. > > Got stuck while a bridge opened for a barge. Shut off the engine. > Turned the key back on, could not hear the fan running. After 5 min or > so, the fans suddenly turned on. I started the car and the temp came > down.The fans shut off again, and the temp rose. Opened the hood > to be sure the plug contacts were not grounding somewhere.. (not.) > > I think in some prior discussion I remember that the )M60x has 2 fan > switches. Apparently they are in parallel. Anyone know if or where > this other switch could be? > > Thanks! > > ___ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > > ___ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
