C-3 Thermostat Recommendation

[Martin N.]

What would be a good thermostat temprature wise for a 74 L-48 with a/c and automatic? I have a ton of paper work from previous owners and none of it shows the thermostat ever being replaced. Summer driving only and we're here in Northern IL. I believe it came from the factory with a 195 degree in it? Thanks for your input.

Marty

[Michael W.]

Re: C-3 Thermostat Recommendation

I believe the 195 thermostats came later than '74. Most people use a 180.

What's wrong with your existing unit?

[Joe L.]

Re: C-3 Thermostat Recommendation

What would be a good thermostat temprature wise for a 74 L-48 with a/c and automatic? I have a ton of paper work from previous owners and none of it shows the thermostat ever being replaced. Summer driving only and we're here in Northern IL. I believe it came from the factory with a 195 degree in it? Thanks for your input.

Marty

Marty-----


I think it's very possible that your, particular, application was originally equipped with a 180 degree thermostat. In any event, I would probably go with a 180 degree. However, I think you'd be alright with a 195 degree, too. I would expect that there are probably very few conditions under which your cooling system would be able to maintain 180 degrees, anyway. If a cooling system cannot maintain the temperature which is the set point of the thermostat, using such a thermostat is not going to gain you much and might even be a disadvantage (i.e. you want to keep the engine temperature as CONSTANT as possible). Remember, a thermostat only controls the LOWEST temperature that an engine will operate at (after warm-up, of course); it does not control the HIGHEST temperature the engine will operate at.

Some folks think the thermostat controls the highest temperature. Mostly, these are "dreamers" who think a thermostat replacement will be a quick and inexpensive fix for their overheating problems.

[Joe L.]

Re: C-3 Thermostat Recommendation

I believe the 195 thermostats came later than '74. Most people use a 180.

What's wrong with your existing unit?

Mike-----


195 degree thermostats were first used in Corvettes for the 1966 model year for cars equipped with K-19. Thereafter, the 195 degree units were used pretty much always for AIR-equipped Corvettes (and, other Chevrolets, too). There were some exceptions in the early 70's, though.

In this case, the 1974 L-48 with automatic and federal emissions was the only application for 1974 that did not use AIR. So, it's possible that it was equipped with a 180 degree. It's also possible that other 1974's, which did have AIR, used the 180 degree. As I say, I believe there were some exceptions to the "AIR= 195 degree thermostat rule" in the early 70's

[Martin N.]

Re: C-3 Thermostat Recommendation

Mike-
The only thing I think is going on with the thermostat is that's either lazy or stuck open, it takes quite some time for the car to get up to operating temp. (about 185 - 190 degrees.) Like I stated earlier I have no paper work from it ever being replaced.

Marty

Marty

[Martin N.]

Re: C-3 Thermostat Recommendation

Thanks Joe, I think I'll go with the 180 and see what happens.

Marty

[Joe L.]

Re: C-3 Thermostat Recommendation

Thanks Joe, I think I'll go with the 180 and see what happens.

Marty

Marty----

I like Robertshaw/Honeywell for thermostats. #330-180.

[John H.]

Re: C-3 Thermostat Recommendation

Marty----

I like Robertshaw/Honeywell for thermostats. #330-180.

Those are getting hard to find since Robertshaw sold their thermostat business to private investors; they also sell to Mr. Gasket, who re-packages the #330-180 as Mr. Gasket #4364.