eightrac

I have a '97 2.8QM with an erratic temp gage. I just replaced the timing belt, tensioner, idler, water pump, penosin coolant (G12) and coolant temp sensor. The gage goes from 1/2 to 1/4 and sometimes near the bottom of the low end of the gage.

Here's my take;

My coolant was sludge, the previous owner put green coolant in it and basically goooed the entire system up. I got it all out and flushed with new g12. I think the thermostat is weak and letting coolant by allowing the engine to never warm up making the ecm think the temp sensor is out of limits.(I only get the code then the car has been running for about 60 miles with the gage under 1/4 from the bottom).

You think I'm heading in the right direction? I should have replaced the t-stat when I did the belt I think.

AudiMick

Yes absolutely, bad news is you are going to have to 90% of the timing belt job again.

eightrac

Yeah yeah yeah.... The story of my life. Once again, I figured if it worked, don't f-with it.

AudiMick

It seems like when you fit a new pump that extra "oomph" overwhelms the spring in the old thermostat.

There's kind of a workround that helps somewhat:

Zip tie the belt to the camshaft cogs. Mark the tensioner and then back it off about 45 degrees. That leaves the belt just loose enough to remove the thermostat cover and thermostat. Once you are done turn the tensioner back to the original position.

Use new bolts in the thermostat housing as the old ones tend to shear off.

Been there .....etc.

MUNDO_AUDI

wow you replaced all the expensive parts but you couldn't replace the cheapest and easiest to replace?

En que estabas pensando? HEHE

eightrac

wow, you're a dick. $37 for a thermostat that was supposedly replaced less than 10k ago isnt cheap.

c rote, douchebag. HEHE

WJM

I have had sticky thermostats that took awhile to break in. As long as your temps are going high I wouldnt be as concerned

eightrac

The thermostat was actually fine. Looks as if the coolant has actually become acidic somehow and had eaten the o-ring away from around it. I replaced it and the t-stat and all is well now. It took me 2-1/2 hours start to finish. Thanks to those who helped.

FYI: A cheap swimming pool pH tester helped considerably in finding why the o-ring was damaged.