Factory Thermostat

[N.W. Buick]

I was curious (o.k. sort of a trivia question ) when the cars came new from G.M. they had a 180 degree thermostat. What temp did the low speed fan kick on at? What was the temp the high-speed one turned on?

 

[earlbrown]

Seems like high speed kicked on at 2something or when the A/C was on. It's hard to say as I haven't had a separate low/high in over a decade (and my high speed switch location was diplaced for a VDO temp gauge).

 

[Phoff]

190 thermostat from the factory.

Low speed fan came on at 208 degrees or if the a/c was on and a/c pressure hit 150psi.

High speed fan came on at 226 degrees or A/C pressure hit 275psi.

Fan would run for up to 10 minutes after the car was shut off if coolant temp was 226 degrees or higher when the car was turned off.

Pete

 

[whitehot1]

Were there different degree temp thermostats installed from the factory depending on where the cars were going to be sold in the country?

 

[earlbrown]

No. From the factory, the thermostat is an emissions device. They like to get the engine as hot as possible for the sniffer and for gas mileage. Pretty much the exact opposite of what we care about.

 

[TurboDave]

Sorry to disagree guys, but I still have my original thermostat that was installed as built in my 86 GN. I can attest to it being the original because I am the original owner of the car.
It's a 180°

 

[1952ray]

Sorry to disagree guys, but I still have my original thermostat that was installed as built in my 86 GN. I can attest to it being the original because I am the original owner of the car.
It's a 180°

Likewise, still have mine to. 180 degees

 

[captndave737]

Mine had a 180 when new and a winter option for 195. I've never seen a 190.

 

[Phoff]

195 is correct. Typo. Small keys on my iPhone. Or fat finger. Lol

I'm going to check some original paperwork I have but I think 195 is what Buick called for in our cars.

Pete

 

[Phoff]

Original GM part number for the thermostat is #3037745 195 degrees.


Pete

 

[TurboDave]

That may very well be, but that's not what came out of my GN when it was brand new.

 

[1952ray]

Original GM part number for the thermostat is #3037745 195 degrees.


Pete

Pete, knowing you I am sure you are right. But like Dave I do not understand. I am 100% sure when I took mine out 15 months ago it was 180 degree. It had 11.6k miles on it then. I brought the car brand new

 

[Phoff]

It may be 180. Buick literature has been wrong before. The hotter thermostat may have been for the non-turbo 3.8ltr.

I'm still digging for more info.

Pete

 

[earlbrown]

It's common to put 195 in cars for mileage and emissions reasons. It stands to reason they were 'forced' to go with 180 to counteract potential warranty engine jobs. It might have been a trade off since they abandoned the water injection.

I could see were the pat number would match a N/A engine as it's common to consolidate parts over time and merge stuff that really shouldn't be.

If I had to run a 195, I'd drill hell out of some steam holes and get it a little lower.

 

[Phoff]

Yes. It looks the like part number was superseded with a 195 but don't know for sure yet.

Pete

 

[Phoff]

TurboDave and 1952Ray were correct.

All 86-87 engines came with 180 stats from Buick.

Looks like at some point the part number crossed over too a 195 stat.
Could have been as early as 1988.

Still working on that.