TOO cold?

Old Henry

Old Henry

Well-known member
Can the flathead engines get TOO cold in the SUMMER without thermostats?

I know this is a weird season to discuss this, but, in light of recent lengthy discussions about not using thermostats in the summer, which is what I've been doing for several years, I've been thinking about the down side of such, even in the hot summer.

I've noticed that when climbing over a mountain in the summer without thermostats the engine still gets pretty hot by the top of the mountain, but then, going down the other side, usually coasting or in a gear to prevent excessive speed, the engine quickly cools down to almost no reading on the temperature gauge. That has always looked real good to me after watching the thing climb going up the hill but, after reading a few things lately about the importance of getting the engine up to proper operating temperature and keeping it there I wonder if that's really healthy on the engine and whether I ought to go ahead and keep the thermostats in even in the hot summer to get the engine up to proper operating temperature quicker and keep it from cooling so rapidly under the circumstances I've just described. I've read some comments that such rapid cooling can do damage, even crack the block. And that, at temperatures below ideal, the oil doesn't heat up enough to boil off water and some water born contaminants as well as the internal air space in the engine below the cylinders above the crank - that needs to heat up quickly to evaporate moisture in there.

What do you think?
 
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I prefer to run thermostats, summer and winter.

I do not have a problem with getting the engine to cool with thermostats installed in the summer.

In the summer, the engine will warm up a little quicker and going down hill as you have described, the engine will maintain operating temperature.

This is my opinion,

Chris
 
Trust me, if Henry didn't think that the engine didn't need them, he DAMN sure would have saved himself a few nickles and eliminated them. The thermostat is there to maintain the optimum operating temperature. It never ceases to amaze me that people still believe that their engine will run cooler with out one. They have nothing to do with running cooler/hotter...they're used to keep the engine temperature in the operating range it was designed to run at...
 
I'm with 345 DeSoto. Removing them will not make it run cooler, in fact it will make it run hotter because the loss in restriction will cause the water to circulate too quickly and spend less time in the radiator.

As far as the uphill/downhill experience, I'd say we all get that whether with or without thermostats, except your summers must be awful cold to drop your temp gauge that much downhill.
 
My 31 tudor sedan runs very cool after running for 45 minuets on the driveway in the winter it only gets warm to the touch. I always thought it should get a little hotter. Does anybody think a four blade fan is to much in the winter. It does get hot in the summer and my wife cant put her feet on the floor on a twenty mile trip. Do I need a thermostat ? Old Henry as you can see my A runs to cool in the winter also. After reading all responces I am still confused. Another Old Man.
 
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I am an advocate of thermostats too. However I am going a bit off topic. You don't have your engine run hotter because the water is moving too fast. If it is in the radiator less time cooling down, it is also in the engine less time heating up. Good water pumps with lots of flow helps prevent overheating. Fortunately a good set of stock 37 and later pumps move a lot of water.
 
jimvette59 said:
My 31 tudor sedan runs very cool after running for 45 minuets on the driveway in the winter it only gets warm to the touch. I always thought it should get a little hotter. Does anybody think a four blade fan is to much in the winter. It does get hot in the summer and my wife cant put her feet on the floor on a twenty mile trip. Do I need a thermostat ? Old Henry as you can see my A runs to cool in the winter also. After reading all responces I am still confused. Another Old Man.
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like the man said if henry thought you needed one in a model a he would have put one in i have six model as all have two blade fans and no stats
 
I had problem with over heating with no terms and with even in cold weather.I,m running terms now with a new raditor and no problem.Its never to cold for a flathead.2 degs last night.
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All things considered, I think I'll give Henry's original engineering a whirl next summer and leave the thermostats in. I have a new engine, new radiator, new higher volume pumps, and new hoses. The system is as close to what Henry engineered for 1947 as it can be, other than the higher volume pumps.

I abandon that philosophy that I've had for years that colder is always better for the engine and that the only reason to cause the engine to warm up to any temeperature is for the heater in the winter. I'm convinced now that there are more reasons than just that to get the engine warmed up to at least 160 degrees and keep it there or above. Although 160 degrees may be ideal, nothing wrong with 170, or 180, or 190, or even 200 degrees. If it does get too hot the radiator cap will open and let off some steam to let me know it. (I don't totally trust the temperature gauge since it always seems to read a bit high.) I just don't see that happening with the system all as designed. It will sure save the effort and hassel of draining the water, removing the hoses, and removing/installing thermostats twice a year.

Thanks for all who gave input on this issue.
 
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I think there is some merit to maintaining a minimum temp on any engine. While working for a Ford tractor dealer in the 60's for a couple of years, I found that Ford put thermostats in all Ford tractors. Having torn down dozens of old engines for rebuild, I found that the end cylinders on every block, whether it was a big truck, six cyl or V8, had more wear than the center cylinders that obviously ran a bit warmer. I run Prestone #330-160 stats in my '50 Ford.
 
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