The Stovebolt Site Forums The Shop Area Engine Shop Thermostat temperatures

I usually use a 165 degree thermostat in the summer and a 180 or 195 degree thermostat in the winter. My dad said that he used to use a 120 degree thermostat in the summer. This would have been in the late 1950's. Surely he is mistaken but I wasn't born until '66 so I can't really know for sure. Has anyone here ever heard of a 120 degree thermostat?

No, and I wouldn't use it anyway.

A 165 opens sooner than a 180 degree thermostat. None of this alters the top running temperature.
In other words, an engine with a 165 degree thermostat will run at the same maximum temperature as one with a 180 thermostat.
If this is so, what is the advantage of a 165 degree thermostat? Maybe the heater will start heating the cab sooner...

Only true if you've put more heat load into the radiator than it can handle. As long as the cooling system is adequately sized, the thermostat will regulate to very close to the thermostat temp. In other words, a 165F stat will keep the engine at 165F max, and a 180F stat will keep it at 180F max. If your cooling system is on the ragged edge, the cooler thermostat would be full open just like the 180F stat, and the engine temp would be fully dependent on the radiator and cooling system capacity.

In the context of the OEM cooling systems on these old vehicles Carl is correct. To the OP a 160 +/- is more than adequate for heating in the winter (ever stick you hand into 160 deg water?) and allows the engine to start dumping heat sooner. I run a 160 year around in my '38 and love it. The OEM thermostat on my '38 is a 160. The heater can run us out in the winter if I run it full bore. Looks like a '59 came stock with a 180. I'd just leave the 180 in it full time since that's what it was designed for. If you're running the cooler 'stat in the summer due to cooling issues you likely have a partially plugged radiator of a lot of crud in the water jacket or both.

The cooling system is fine in my truck. The heat is another story. The cab is pretty drafty going down the road. 180 degree water going through a heater coil will provide warmer air than 160 degree water will. The water flows through the heater core with the thermostat open or closed so the heater will start working the same time with either thermostat. It will just get the air that it blows hotter with a hotter thermostat.

PS I just wanted to know if they ever used a 120 degree thermostat in anything. My truck is working fine. Thanks for the responses though.

Does anyone have a 216/235 with a 165 degree thermostat which does not reach 180 degrees on the gauge once its warmed up?
Carl

It depends on the time of year with my '38 Carl. During the colder months it stays right about 160. During the warmer months the gauge shows between 180 and 200 depending on the circumstances. My '38 isn't real air tight and my 160 allows the heater to keep us quite toasty. The OP's vehicle came with a 180 so he should stay with that IMHO.

I run a 160 in my 216 and generally sits on the "8" of 180 on the gauge when warmed up. Only time it gets up into the "0" is on extended idling. It's never went past the "0" (knock on wood). Cold weather it's between the "1" and "8".....

On the other hand the 180 thermostat I tried once, routinely ran in the "0" and would creep past it on long idle times.

http://chevy.oldcarmanualproject.com/chevyresto/59ted19.htm

My 1954 235 "standard" thermostat is rated as 160 degrees - it was rated as being fully open at 176 degrees.

Sounds like no matter whether one uses a 160 or a 180 degree thermostat, a Stovebolt in good working order wants to run at 180 degrees.
My question is, what is the benefit of a 160 thermostat versus a 180?

To answer the original question, yes you can find a 120 degree T stat for marine uses. Not sure if it fits our trucks.

I'd run the truck without one instead.

I run my truck with a 160 tstat. I also use a "water wetting" agent in the coolant. Truck runs near 175. Reason I do this is to keep the engine cooler in summertime traffic.

I also uses a manual valve on my heater hose to keep the cab cooler.

As klhansen said, the engine will run at (around) the thermostat temperature, unless some part of the cooling system isn't working at 100%. Then it runs hotter. Engines don't "like to run at" a particular temperature.
No thermostat:
worse mileage
dirty oil
corrosion
extra choke use
later heat
slow warm up

Advantages: you don't have to worry about it - it's always wrong so it can't fail.

Thanks SWEET. That was all I was really asking. I have a 1967 250 ci engine in my truck so it really doesn't matter what thermostat it originally came with. I really don't think that a truck being used in Nome Alaska would run at it's best with the same temperature thermostat as a truck being used in Death Valley. I would think that GM would probably just put a medium thermostat in their trucks and then count on the customer to use a little common sense and adapt to his or her particular needs. This was a time when most men could actually work on their own cars. It's not like that today though.

Many new cars were made in at least 2 different states of tune WRT jetting (cold, hot, high altitude), and probably thermostat. After 1963 some cars are special for California only.

Now that makes sense!