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Hey Gang...

Well, I finally got fed up with the inconsistant readings that I was getting from my original temp gage, and bought a mechanical one from Princess Auto (...it actually looks very vintage and correct...I just need to paint the bezel to match the dash...)

Anyways, now that I will have a gage that works, I need to know what the typical operating temperature range is for a M37 in good working order (ie. with my BRAND NEW 4 core rad).

Thanks

Ty

Mine runs at around 200 degrees F if this helps.

my truck only gets to 180 deg and it has the 251 CDN engine...

If the cooling system is in good shape your engine should maintain what the thermostat is rated at, or pretty darn close anyway.

Good afternoon,
I just rebuilt my orig 245 eng, had the radiator re-cored, new water pump and a new thermo.
she runs at 180 deg. I put a 180 thermo in, so yours should run at or close to the thermo design setting.
BOB

Mine has consistently been 180.

Awesome...thanks for the numbers, guys. The thermostat is in, the bezel is painted, and I just need to take it for a spin to see how it works.

Ty

UPDATE....

Well, I changed the fluid in the axles, transmission and transfer case today (...used Royal Purple 40wt as recommended by Charles Talbert...) and took the truck for a spin.

Firstly, I was impressed at how much smoother the shift were with the new fluid. The characteristic gear whine that I have been listening to was also gone.

As for the temperature, I needent have worried about it...the mechanical gage never showed higher than 170 degrees. Guess it must have a summer thermostat.

Thanks again for the info, guys.

Ty

ty
You engine running temp should be directly proportional to the temp ratting of the thermostat, if you are running a 180 deg t stat your temps should be within that range +or- 5 deg and if you are using a four core radiator I would suggest running a 195 t stat to help keep the moisture build up out of the crank case which will help the engine live a long happy life. If the temp is getting over 215 deg you have other concerns. By using a lower temp t stat will give you a adverse affect by not keeping coolant in the radiator long enough to cool it and as you drive in higher temps this will lead to a premature over heat condition ,I have had some disagree with that but it is easily proven here in the desert.
hb

TY,
I have been running around in the 95 degree humid Ohio weather all summer. I have the 180 thermostat and she runs at just that when hot

David
I would like to believe that is a real temp reading but it is not likely a good reading, your engine has to operate more than a few degrees above ambient temp or the engine will never warm up enough to keep from fouling the spark plugs or burn off the excess gasses and moisture from the combustion chamber that eventually end up in the oil pan, anything under 160 degrees is running the risk of you oil turning to sludge and premature bearing failure the best temp is around 180-190 degrees, Something is just not right sounding with the reading you are getting and I do not believe yours is running that cool! I will bet that it is running closer to 180-195 You can do a quick check by using a hand held laser thermometer and take a reading at the block and then pull the dip stick and check the oil temp, if still running cold take the t stat out and see if it is hung open. Or try another temp gauge? Take it for what it’s worth!I have been a journeyman automotive tech of 35 years and with a parallel aviation tech careered with millwright/boilermaker experience.
hb