Justin Browning

Ok, I think I have a sticking or a completely non functional thermostat. When driving the car from when the engine is cooled all the way down (after 4 hours) the temp gauge climbs to the last white mark (at the top) in about 5-10 minutes. Then about 5-10 minutes later, it climbs higher, to just below the red. It will then drop back down to the white line after varying times, (which I think is why the thermostat is sticking). The fans seem to be functioning normally. I checked the upper radiator hose and it is scolding hot, while I can hold the lower radiator hose all day and not even think about getting burned. Also, I have had the timing belts done with a new H2O pump and I have new oil as well as a bled coolant system. The gauge has never given me trouble before, so I beleive it is the thermostat.
Thanks in advance,
Justin

mark944turbo

I have the same problem, and I also did a recent waterpump/thermostat/cooling system bleed service. The only thing that scares me is this just started happening recently with the warmer weather. It was normal all winter. Anyone else?

Justin Browning

Good point, I failed to mention the weather thing, it is the same for me.

Luis de Prat

Guys, this sounds like a relatively simple faulty cooling problem with a good prognosis, or it can be a leaking headgasket. The latter is less likely but don't rule it out entirely.

Items to check under the first scenario:

*Blocked radiator (spring is a good time to change out your coolant and have the radiator checked).
*Inoperative thermostat
*Failing cooling fan relay (this was my situation)

Under the second, dreaded scenario, you've already taken care of all these items, and the temperature gauge continues to climb even during highway driving...

HTH

Kevin Baker

Sounds to me like a stuck thermostat. One question, did you both change the little spacer thing that goes behind the thermostat when you did the waterpump, and less likly, is the t-stat in the correct direction?

Justin Browning

Well, changed the thermostat with a known working one (did the boiling water test) and the gauge still goes to the same region. Also, I have now lost all heat from the Climate control. So the gauge says that I am in the red, but the heater won't blow anything but outside temperature air...

tazman

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Justin Browning:
<strong>Well, changed the thermostat with a known working one (did the boiling water test) and the gauge still goes to the same region. Also, I have now lost all heat from the Climate control. So the gauge says that I am in the red, but the heater won't blow anything but outside temperature air...</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">It sounds like you still need to bleed your coolant system better <a href="http://64.226.197.185/Paragon/Tech/944_coolant_flush.htm" target="_blank">http://64.226.197.185/Paragon/Tech/944_coolant_flush.htm</a>

I have the same problem as you guys and when I squeeze the lower radiator hose I can not fell any pulsation as I would expect to with water running through it. I plan on removing my thermostat this weekend testing the car without one to see what the lower hose feels like then putting a new thermostat in. Hopefully the snap ring doesn't give me that much trouble!!

Kevin Baker

Is the t-stat installed facing the correct direction? I mean if the water in the engine is getting hot, but not contacting the correct side of the t-stat it will not open. this could also be the cause of the ambient temp air to climate control as the hot water for the heater core comes off the water pump before the T-stat. IIRC

mark944turbo

I know I put the T-stat in the right way and with the spacer (I did it myself). My heater does work, so it looks like we both have a different problem. I am going to investigate this weekend and I will get back to everyone about what I find.

tazman

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Kevin Baker:
<strong>Sounds to me like a stuck thermostat. One question, did you both change the little spacer thing that goes behind the thermostat when you did the waterpump, and less likly, is the t-stat in the correct direction?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Is it required that this spacer be changed? When I ordered the thermostat I asked for everything I would need and was just given the snap ring and the seal with the thermostat.

Justin Browning

Yes the t-stat is in the correct way, but if the cooling system was not properly bled, wouldn't I still get heat?
Tazman, I suggest the GM Brake something or other tool. It looks like the snap ring pliers, but short and has a thumb wheel on it.

Kevin Baker

Mark, check your fans, are they coming on at all? They have 2 settings a low and high depending on temp. If the thermo-switch in the radiator is faulty, it may not send the low signal to the fan relay. HTH do a search in the archives for fan relay or thermo-switch for instructions to test/bypass to test thermo-switch.

Kevin Baker

Justin, not sure about the bleeding being an issue with the heater or not, I suppose it could play a role if the air pocket was in the heater core and the t-stat didnt open. It sounds like there is something preventing the water from leaving the engine to cool, enter the heater core. One suggestion is to pull the t-stat out, bleed system, run car and see. That would tell you if there is something other than the t-stat to blame. HTH

tazman

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Justin Browning:
<strong>Yes the t-stat is in the correct way, but if the cooling system was not properly bled, wouldn't I still get heat?
Tazman, I suggest the GM Brake something or other tool. It looks like the snap ring pliers, but short and has a thumb wheel on it.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">If the coolant system is not bled properly sometimes you won't get heat because the heater core is filled with air instead of hot water.

GOBOGIE

Have you ck'd to see if you have intermix?