thermostat question

[jimainiac]

I still say, what are the odds of getting four bad thermostats in a row? That said, I have gotten two bad replacement windshield wiper motor units in a row from NAPA, for the afor mentioned '98 Chevy truck. It can get very frustrating.

There could be something to the air pocket thing, but it seems like it would eventually work itself out, I would think.

 

[redharley]

I work in a fleet garage with 90% GM and aftermarket t-states will somethimes do that.We do not seem to have any problems as our trucks are on the road 6-10 Hr's a day.We use stant and will notice a wider temp swing than the Gm stats, another issue could be if you replaced the radiator in the past,if a thicker one was installed for towing reasons this will also cause a wider temp swing.If you have or know someone with a $50 point and shoot temp gauge and direct at your t-state housing you can see what temps you are really running.Keep us posted

 

[Hooked_on_HP]

The thermostat is not in upside down. I am thinking about getting one strait from GM. I have even went as far as changing where the heater hose returns. The one heater hose returned coolant to the radiator and I changed it so it returns back into the engine. The shape of this thermostat is different than any other Chevy thermostat I have ever changed. I have had big block Chevys forever and never seen this style thermostat in one. I am not sure what the lower spring is suppose to do.
Bill

 

[jimainiac]

Yep, that's right side up, alright. Sorry, I just had to ask. I went looking for the old one I took out of the truck last year while changing coolant, but I guess I chucked it. I did find the thermostat I just took out of our backup generator, 4 cylinder Mitsbishi engine, and it looked the same as your picture. It has that lower spring, as well.

I think NAPA has pretty decent quality parts as a rule. Nobody gets it perfect all the time, and you can't help notice that some of the stuff isn't as well made as it used to be. Seems to be the way of the world.

 

[Treemonkey1000]

I am a bit mechanical but I tossed your question at a friend of mine that is a bit of a whiz kid. Here is his reply for what it is worth :

"Interesting problem which I've seen before and was caused by a bad thermostat. To resolve the issue I switched from Stat brand to a performance, high flow thermostat from Mr. Gasket. Temperature is now rock solid at the rating of the thermostat, 180 degrees. Go figure..."

 

[Hooked_on_HP]

Treemonkey, thanks for the idea.For some reason I never thought of buying a thermostat from the companies I buy my race car parts from.. I am sure some of them make some quality thermostats.
Bill

 

[Stimw]

As for fuel mileage, I bought a used 1989 1500 Chevy, 4.3. The heater barely put out. I changed thermostat (195*) (had original 195* in it). I got 2 more miles per gallon!! And the heater worked great.
The computer adds more fuel to a colder engine. I see/hear too often people changing a computer vehicle T-stat to a 180* or 160*. Don't do it! If you have an overheating problem fix that. The wrong thermostat is not a fix.

 

[timswi]

Treemonkey, thanks for the idea.For some reason I never thought of buying a thermostat from the companies I buy my race car parts from.. I am sure some of them make some quality thermostats.
Bill

I'd do that too...I get my stuff from Summit Racing for the trucks and the Chevelle. Some of this over the counter stuff is pure garbage. I have run into this t-stat problem as well. They work, but the temp swings are too wide.

 

[Hooked_on_HP]

So far No good. Aparently no one in the hi perf world makes a 195 thermostat. I checked Summit and Jegs and neither has one. I did a google search and could only come up with Stant.
Bill

 

[Diamondpilot]

My father is VP and plant manager of Stant. He has worked there for 42 years starting in the maintenance department, then on the line, then up though management. Something like this would never happen today but anyway they make a quality thermostat. I am not just saying this because he works there but because they are a good home grown Indiana company that makes aftermarket and oem parts. Give them a try.

If you need any inside info or technical info give me a PM and I will pass it on to the guys I know in the R&D dept and the engenring guys. Many who work there are ex motor heads, race car drivers, crew members, ect who know this stuff.

Chris