The Stovebolt Site Forums The Shop Area Engine Shop operating temp

Hopefully somebody will tell me I'm overlooking something very simple...all of the sudden (no changes of any kind to my '50 3100) my engine's (216) operating temperature dropped from about 190 to 160 degrees. I thought that the thermostat (160 degrees) must have been stuck (it wasn't), so I replaced it, to no avail. I'm afraid that the new operating temp. is too low and will prove harmful to the engine, causing unnecessary wear and tear. In addition, the engine isn't warm enough to heat the cab.

And even if running it at 160 degrees is O.K., not knowing why the operating temp. would drop 30 degrees is irritating.

Any help/suggestions would be greatly appreciated.

Richard

starsfan,

I think the original thermostat for a truck 216 was 160. I do not think that temperature will hurt the engine.

The radiator cap on a 216 was 0 psi. (Some automobile 216s might have come equipped with a 4psi cap.)

Many people seem to change to 190 degree thermostats and 4-7 psi caps.

Sorry, I have no guess as to how/why the temperature has dropped from 190 to 160 degrees.

If I am wrong, you can bet that soemone will correct me.

Tim

Back when they were new we used to run 160 therm. in the summer & 180 in the winter. If your radiator is in good condition I would run 180 them. with 4-7 lb. pressure cap all year round. Your original therm. must have been defective if it was a160 & ran at 190.

Thanks for the input. I'm going to put in a 180 degree thermostat and see what happens. I'd still love to know why the temp dropped so suddenly and has stayed there. Thanks again.

You will probably never know. Could have been something blocking the water flow, fan belt slipping. Did you do anything like adjusting your valves?

Like the guys said, 160 was stock, most of the original trucks ran 180 in the winter. One more thing to do is to see if your temp gauge is accurate. I use a meat thermometer that I know is pretty close. Simply wash it off and put it back in the drawer when your through.

4 lb cap was introduced in 52. It is what a lot of people with older trucks use as a replacement provided the heater core and radiator are in good shape. The added pressure raises your boiling point by a few degrees, won't make the engine run any warmer in the winter, though.

Yeah, I checked the ACTUAL temp. with a candy thermometer in the radiator...the temp. guage is on target. Thanks again for everybody's help.

You're probably right, Fred, I'll probably never figure out what caused the precipitous drop in temp.

Whaddya' think about this theory? Maybe the 160 degree thermostat was stuck in the closed position, thus causing the temp to operate at 190 degrees (or would it heat to well beyond that with a stuck thermostat?). Then, for some reason, the thermostat unstuck on its own and that's why I'm now hovering around 160 degrees. That's the only thing I can imagine. Thanks again for all of your responses.

Richard, have you taken some sort of thermometer and checked the actual temp? Could be that there is a problem with your sensor or gauge. Just an idea.

Yeah, I've checked the actual temp. with a candy thermometer and the gauge is dead on.

I'd say your theory is 'bang' on about the stuck thermostat. I've sure seen that happen. Temp goes right off the clock and you have to shut down the engine. A little while later, on re-start, the thermostat opens and the gauge just soars back down to 'normal'.