Late coming in on this and have not read other posts but if your problem came after any cooling system work, hose replacement, etc, make sure you don't have an air lock in the system, which frequently will result in no heat from the heater while everything else functions normally. Would not suspect a water pump problem if the motor is not overheating or signs of leakage around the pump. BZ
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bruce Labitt Sent: Sunday, April 10, 2011 7:22 PM To: [email protected] Subject: Re: Diagnosing Bad Water Pump, or Heater Core or? On 4/10/2011 5:25 PM, Ross Kuhns wrote: > If the hoses are only a year old, they should come off; > take a pair of slotted type pliers/grips and you can > usually work them back and forth a touch as you pull - > tool is set perpendicular to the pipe/hose. Of course > don't squeeze too hard, those pipes are soft. If you try > to confirm flow thru the core, make sure not to use too > much psi, system doesn't run under too much pressure (what > 13psi?). > > Ross > > > > On Apr 10, 2011, at 4:34 PM, Ken Bogart wrote: > >> I would flush the heater core to verify flow. If its >> blocked and needs replacement, a temporary bypass will >> certainly work to keep you on the road. >> >> >> Ken Bogart >> ----------------------------------------------------- >> 96 Montego Blue FFS Coldside (His) >> 97 Black & Tan (Hers) >> 90 Crystal White (sons) >> ------------------------------------------------------ >> http://www.miatacare.com <http://www.miatacare.com/> >> http://www.cincimiata.com <http://www.cincimiata.com/> >> http://www.bcchallenger.org <http://www.bcchallenger.org/> >> MiataMail.com <http://MiataMail.com> list owner >> >> >> On Sun, Apr 10, 2011 at 2:32 PM, Bruce Labitt >> <[email protected] >> <mailto:[email protected]>> wrote: >> >> I'm trying to diagnose if I have either a bad water >> pump, or just a clogged heater core. The hose at the >> output of the heater core has been spliced to insert >> a GM temperature sensor in the line. [Other than the >> temp sensor splice, the cooling system is stock.] >> The GM sensor is reading correctly - it reads cold >> and the heater line *is* cold. However, at the back >> of the head, the sensor which goes to the dash reads >> very hot (after the engine has warmed up, of course). >> It is as if there is no flow out the back of the head. >> >> Things I've tried: >> 0. Removed thermostat, put housing back. Still >> overheats. Have new tstat, but have not installed. >> 1. Remove GM sensor splice, and inspect the inline >> housing. Can see daylight through the hose >> connections. Conclusion: temp sensor housing is not >> clogged and not impeding coolant flow. >> 2. Added classic coolant flush tee in place of the >> inline temp sensor. Flushed 12 gallons thru system. >> Pretty ugly looking coolant, if I must say so. It >> still does not quite look like clean water, but it is >> far more water like than before. >> 3. Put back GM temp sensor. >> 4. Refilled with water. Installed a burp bucket on >> radiator, ran engine. Filled bucket 1/3 way. Bottom >> rad hose does not seem like it is full of coolant. >> Feels like it is not uniformly hot. Tried squeezing >> hoses, etc to burp. Not much happened with respect >> to coolant level. Engine heated up - back of head >> sensor showed quite warm - heater core loop quite >> cool to the touch. >> >> What I'm going to do next: >> 1. Bypass heater core. Is there an 'easy' way to >> get these hoses off? I cut them when I replaced them >> last summer. Are they 'welded' on by now? >> 2. Maybe, flush core, if above works. >> >> Anything else? >> >> _______________________________________________ >> Miatapower mailing list >> [email protected] >> <mailto:[email protected]> >> http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower >> >> >> _______________________________________________ >> Miatapower mailing list >> [email protected] <mailto:[email protected]> >> http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower > Well, I didn't quite do things in order. I flushed the heater core. (Pulled heater hoses, attached garden hose with anti-backflow to one side, attached 6 foot hose to bucket on the other side.) Nasty, but eventually ran sort of clear. So it is NOT the heater core. Loads of water ran through it - it does not appear to be a restriction. No water in the cabin, either - thank goodness. Then I back flushed the head. In the water neck in the back of the head - out the other pipe to the heater core. Hooked everything up again. Filled through burping funnel. No apparent flow through the core. However, the thermostat is NOT installed. Is the thermostat required for the heater core to get water flow? I have a standard new Stant thermostat. Do I need to drill out the 'jiggler'? Hole size? Hole is up, correct? Is there a good test for a water pump? Looks like I'm running out of ideas. Carried off 50 gallons of 'water'. What a fruitless day. Got insight? Thanks _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower _______________________________________________ Miatapower mailing list [email protected] http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
