VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Thermostat needed? Yes or no

Would my 37 run cooler with a thermostat or with out? The reason I ask is I drove it the farthest I ever had and for about the first 20 miles ran ok about 190 but the last 5 miles of stop and go traffic she rode up to 212 and boiled over when I got home. It did not have the thermostat installed. I have a brand new recored radiator new water pump. The out side temp was only about 80-85. I do have a new thermostat but just not installed I thought it run cooler with out but maybe not.

For what it's worth, I've always been told it's best with a thermostat as you need some restriction to slow the water passage down and give the radiator time to cool the water. I have a 160 degree in my 1940, have ran it both ways, with and without, it seems to do better with the thermostat.

190 sounds a little high, and I agree that a thermostat would probably help. It certainly couldn't hurt, and at least now you have baseline performance to compare it to. Let us know how she runs with the thermostat in place.

Coach

I HAVE A 160 THEROMSTAT I WILL GIVE IT A GO TOMMOROW and let you know what I find out. Thanks

The thermostat really won't make a difference for overheating. Your car should not have boiled over under those conditions. Did it actually boil over or did it puke out a little water when the engine was shut down? If you over fill the radiator this will happen. I keep mine just high enough that you can see the coolant when cold and about 2 or 3" below the cap when hot.
My '39, which had a new core many years ago, will run at about 180 in 80-85 deg weather. In stop and go traffic it could go higher if I have been traveling at high speeds. Also will almost peg the needle when shut down after high speed driving in hot weather. Would consider all this normal for a 1937-40 engine as they tended to be hotter running (poorly cooled) compared to the 1941 and up. In 1941 they made some major improvements in the cooling system.

NEEDLE WAS PEGGED BEFORE I SHUT IT DOWN IT SURE SEEMED LIKE IT BOILD OVER. AS SOON AS I SHUT IT DOWN AND GOT OUT IT WAS MORE THEN PUKEING A LITTLE IT WAS GUSHING IT MIGHT HAVE BEEN A LITTLE OVER FILLED BUT IT WAS RUNNING HOT.

For some reason most all of us to tend to 'over fill' our radiators. Even after we are told otherwise. Or read posts like Gene's above. Must have taken me 20 years to 'learn' not to overfill. (Translation of overfill: fill to the very top.)

Suggest you follow Gene's excellent advice and give it another go....

Also suggest you follow Gene's advice provided on this matter a week or two ago.... give it a little throttle in the stop-and-go traffic to get the fan moving a bit faster.

Bill.

Its possible that you have a cracked head. Common . Pull the plugs and see if one has rust or an unusual deposit.See if coolant bubbles when engine is running. There is a problem some where if its running that hot.

I was thinking that in the back of my head but did not want to here that.I will pull the plugs today and see if any of them look different. Could it may be just the head gasket?(WISHFULL THINKING)Thanks Gene

If the problem is in that area its the head 99% of the time.

Tim,
Thought I would share a couple of things I've done on my 40 that might help, I very seldom go over 180 degrees except when I turn it off: (1) I built a metal shroud that fits between the Hood latch plate and the Radiator (top of brace) it directs the air through the radiator rather than up and over. (2) I added a 6 volt parade fan on the front of the radiator. Use during heavy traffic or a lot of stop and go. The air flow from the fan is equivalent to about 25 mph when stopped. (3) I added an over flow tank which has eliminated the puking on shut down.

Hoping this helps, Wes

Another possible cause. If your block has not been cleaned out the rust from the blocks is moving to the radiatior core. :eek:

I checked the plugs they all appear to be about the same color so I will flush the block maybe run some sort of cleaner through it first drain and flush flush flush. Maybe some rust did plug up my new radiator cause like I said the first 20 miles or so she ran great about 180 - 190 then the last 10 miles is when I started to have problems this is the farthest I have driven it so I suppose my new $450.00 core could be plugged already.What would be best to use to flush it out? any flush "Stuff" Like prestone

Tim, if you open the petcock valve on the block does water come out? If not you need to unplug the petcock hole and then flush out your motor. I had the same problem and when I finally got water flowing out of the block I flushed it for a very long time with the motor running. You won't believe the crud that comes out of the block. Good luck...Oscar

Did you use any type of flushing product? Or just water

As per Chevgene's advice, I used the Prestone Radiator cleaner and it did a good job on my old '31 radiator and motor. Also used muratic acid as Chipper recomended and that also worked out quite well.

I used Prestone as Jerry said but I didn't use acid. I think Gene said try the Prestone first and we will go from there. The cleaner worked fine. You want a good strong flow when the water comes out of the petcock on you block. My motor now won't go over 180 degrees. Even in 100 degrees stop and go traffic it stays nice and cool. Flush it well and get all the crud out. Good luck...Oscar

Thanks! Thats my plan tommorow. I have a parade on the 14th so time is running out I need to getr COOOOOOOOL!

Thats strange, most prades are on July 4th.

I see that your car has been painted. :)

You can flush out the core by removing the upper and lower hoses and apply hose pressure at the top, hoping to force the rust out of the bottom. Do the smae with the bolck with the thermostat removed so the water can really flow thru. As stated, remove the entire petcock and stick a wire in the hole and poke around. You will be surprised as to what will all come out. It is impossible to get all the rust out but the loose stuff should move out. I always keep a can of the Heavy Duty cleaner in the trunk of all my cars. I have never needed it but others that I travel with have used it.

Yes I finaly gotr painted been working all weekend getting everything put back on the car. The car is going to be in a parade on the 14th for a 100th annversary of the town my Dad grew up in and where the car came from and my 91 year old Grandmother is going to be in period colthing and riding shot gun. my Dad used to get rides to school in the winter in this car when their neighbor would go to town to bring in his milk cans that he hauled in the trunk.

Cracked cylinder heads on 1937-1940 Chevrolets. I have heard that 1940 Chevies have/had a tendency to crack. If true, why?

The old 3 main bearing engine heads seemed to crack easier than the 1937-40's. The 1937-40's were a little improvement. The cracks usually developed after overheating the engine, or overheating and pouring in cold water. The engine should always be allowed to cool down before adding water and the engine should be running when the water is added. When these cars became "older" owners would just dump in water when and where required. The common place to find the cracks is in the valve seat area between the intake and exhaust valves. I replaced the cracked head on my '39 and do have a spare new one. Probably will never use it.
You will find cracked heads on 1941's and up but not as common.

Well I do believe the flushy flushy did the trick. When I took out the block drain it oozed out rust crud (Looked like Poo)I first flushed most of the crud out Ran the prestone through it flushed again. Took it for about a 10-15 mile drive stayed about 170-175. When stopped maybe about 179-180. What a relief usually with my luck I would be pulling the head off looking for cracks. :grin:

Tim, I went through the same excact thing you went through last year and I know the good feeling you feel right now. This is why I love this sight. Gene and Everybody, you are the best...Oscar :cool2:

I would always keep a thermostat in place. When installing a new t-stat, drill an 1/8" hole in the flange so that air cannot be trapped upon a fresh fill and startup. Heads are cracked that way occasionally due to an air lock.