Thermostat location

[Tom Douglas]

I have a 1941 Cadillac Coupe Series 62 with original V8 Flathead engine.  Can anyone tell me where the thermostat is located? I have an original MoToRs AUTO REPAIR MANUAL that tells what kind of thermostat the vehicle has but they dont reveal where its located on the engine. HELP - PLEASE - THANKS!

[JIM CLC # 15000]

Tom, if your engine is like mine, it does not have a thermostat, as most cars have. Check in front of your Radiator to see if you have shutters.
If you do, the shutterstat will be located in the top tank of the radiator.
The shutters should be closed untill the engine gets to normal operating temp, then the shutters open.
If you have need for a new shutterstat, they cost about $135 or more.
I plan to adapt a shutteratat from a diesel engine to my car
Good Luck, you will know it when you see it, Jim

[baxter culver #17184]

If your car has a shutter assembly in front of the radiator, the thermostat should be located in the upper left corner of the radiator (facing the grille) and is connected to the shutter assembly by a long rod.  the thermostat opens and closes the shutters to allow or restrict airflow thru the radiator.  My master parts manual says that is the location for the thermostat in 39 thru 41 cars.

[Tom Douglas]

Thanks, Baxter.  My MoToRs AUTO REPAIR MANUAL says. On 1935-1041 cars, the thermostat is of the bellows type and operates the radiator shutter.  But, it doesnt tell exactly where its located. Tom

[Doug Houston]

One little tidbit here. When the shutter thermostat fails, it fails with the shutters CLOSED. While I still have stats on all of my V8s, ands theyre all working, when one of them goes bad, Ill wire the shutters open, and forget the thermostat. I recently had the radiator re-cored for my 38-60S, and had a plate soldered over   the thermostat hole. Even in the northern states, those engines dont exactly make ice cubes.

[Bill Ingler CLC#7799]

Thermostat and shutters were put on our cars to keep the proper operating temp for the engine under most temperature conditions. To wire open or eliminate the thermostat might be OK if you know that you are only going to drive your car in summer temps but not a good idea if you also drive your car in winter temps. Case in point and here is my reason for a working thermostat. I just returned yesterday with seven 40s Cads from a four day trip from Phoenix to the high country of Northern Arizona and the Grand Canyon. We had one 40-60s, four 41s and two 47s. We all had functioning thermostats and darn glad we did as the temps got down in the low 30s with snow. Normally my 41 with a standard opening thermostat will keep my temp gage at the mid point with shutters fully open. The shutters start to open at 160 and are fully open at 175. On this trip at 60 mph and with temps in the 30s the shutters were just barely cracked and my dash gage was half way between cold and mid point. The heaters were working but really not putting out a lot of heat. All of our 7 cars said the same as to engine operating temps at these lower temps.I would hate to guess what my engine temp would have been if I would have had my shutters wired open. The flat heads were designed to operate with working thermostats and working shutters.

[Baxter Culver #17184]

My 39 60S was purchased with the shutters wired open--the thermostat had failed.  I finally found one at All-Cads and got the shutters working again.  The t-stat is pricey!  A friend says he will fabricate a cable device to open and close the shutters if his t-stat ever fails.  I will too if this new one goes away.  But I agree with Bill Ingler.  If your radiator is fully functioning, you will need the shutters to keep the engine at a proper operating temp and keep the heater (s) working.  Unless you live in Panama.

[Eric Quarnstrom CLC #17675]

Instead of soldering over the hole or running a cable to the dash why not replace your radiator with a later year radiator. When purchasing parts for my 40 I nievely bought a radiator that I was told was for a 40 but after trying to figure out where the thermostat was I came to the conclusion that the radiator was for a later year. It fits in the frame the same but has no hole for the thermostat and uses the inline thermostat.

What do you guys think?

Eric Q.

[Bill Ingler CLC 7799]

Eric- If I would replace my 41 radiator with a 42-48 then I would need to also change my water pump as the 42-48 water pump had an inlet pipe connection and hose from the top of the water pump to the left head elbow water outlet which is now necessary since on engine warm up this allows circulation of the water until the themostat opens. Next I would need to replace the left head elbow water outlet on my 41 engine to a 42-48 as described above and then I would need to replace the entire aircleaner with the proper 42-48 aircleaner(depending on if you had a Carter or Stromberg carb) as the 41 aircleaner will not fit since the 42-48 radiator has the themostat mounted at the top back side of the radiator inside the water inlet.The addition of this water inlet on the 42-48 radiator does not allow space to fit in the 41 aircleaner. With all the changes need as described, you will find this will cost a lot more than $130 the price of a new 41 thermostat plus now you have a cobbled up car as to originality.