Anyway to definitively test the water pump without pulling the timing belt?

Do I need to install the thermostat to positively identify this? I left it out while messing with the system to try to minimize the suspects.

-Bruce


On 4/10/2011 8:10 PM, Bill Bowser wrote:
Sounds like it could be the water pump to me. Many years ago I had a similar problem. It turned out to be a bad water pump. The impeller had come lose from the shaft. It didn't vibrate or make any noise, it didn't leak, and it didn't pump any water either. You couldn't tell anything was wrong by looking at it, but when you restrained the impeller you could easily turn the shaft by hand. I showed it to a couple of mechanics who said they never saw anything like it.

Bill Bowser

On 4/10/2011 7:58 PM, Bruce Labitt wrote:
On 4/10/2011 7:42 PM, bill zimmerman wrote:
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 problem - overheat - radiator cap let go - coolant everywhere. Replaced cap, added water - trouble ever since. Engine overheats.

Could be air lock. How do you get rid of it? I used a coolant funnel attached to radiator cap. Attempted to squeeze hoses... Car is not level right now. Front end is on jackstands. Problem?

-----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
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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?

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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
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