I am a new owner of a 73 350 with a stock engine with A/C. When I drive the car it always goes to 210 on my original style temperature gauge (right in middle). I live in Arizona and have only been driving mostly at night due to temperature. I just brought the car from the East Coast and I probally have a 195 Thermostat. From the research I have done, I have the bottom air deflector, the correct shround, and rubber around the radiator.

What would you do to get the temperature down? Thanks for any help.

 

If everything is right and in good working order, simply putting a 180* thermo will decrease your running temp down to 180-185*.

 

Just installing a lower temp thermostat will NOT guarantee that the operating temp of the engine will be any lower. It could be...or it might not. The T-stat merely establishes the lowest temperature possible for your car's cooling system. Since your engine operates even higher than the T-stat rating, it is doubtful that exchanging the 195* stat for a 180* unit will make any difference at all.

The most common causes for cooling system problems are that the radiator fins are "limed up" from impurity deposits over 40 years (requires using radiator cleaner to remove them); the thermostatic fan is no longer functioning as it should; the lower radiator hose is collapsing during operation {pump suction line} and coolant flow to the radiator is severely reduced; the T-stat is not fully opening; the engine timing is way off causing the engine to run hot.

I lived in Phoenix area (Goodyear) for 5 years and know how the heat can make it difficult for the C3 system to run reasonably cool. But, if the items listed above are resolved or already OK, there should not be a problem. In the end, you should be able to run during the heat of a summer day with A/C on and it (or you) should not overheat.

P.S. Just throwing money at the problem by purchasing new hardware...when you haven't really determined the cause of your problem...is a waste of your resources. One or more of the above items is causing your concerns. Investigate first; then resolve those items.

 

Whenever you get a new old car, it's wise to flush the cooling system and thoroughly clean the outside of the radiator/condenser too. Then check it with a temp gun and go from there.

 

Are you saying that 210*F with A/C on in Arizona heat is too high? I would say it is normal. Water boils at 212*F and combined with anti-freeze in a pressurized system the boiling point is much higher than that.

 

I can tell you that my SB w/A/C and 160* stat (it didn't change the stabilized operating temp, but it did slow down the rate of engine heating) ran around 200* during a summer day...and ran upwards of 210* with A/C on. That is still "cool" by engine standards--but warmer than I wanted to see when the engine wasn't really doing any work.

To do much better than that, you probably need to install a larger radiator. That, alone, will make significant temp reduction.

 

Thanks for the help. Just to clarify, the A/C belt is hooked up, but it is not running in the car. I probally need a new compressor.

Additional Questions:

(1) How do you check the radiator fins? I imagine you have to take the cap off and just look in there? My cap says "closed system, do not remove". I am assuming it is still ok to remove it?

(2) How do you check the thermostatic fan?

Thanks for getting me squared away.