1940 Radiator issue

wspiker

wspiker

Senior Member
I have a 40 Tudor Deluxe. It runs and drives GREAT! However, after I have driven to a destination, it loses a gallon of water/coolant from the radiator. When I was replacing water/coolant in the radiator, I started the engine and see that the water pumps moves the water through the engine and radiator, it would appear, in perfect volume.

Can someone tell me why I lose water through the overflow when driving? And what I can do to correct it. It doesn't appear to be overheating. I have a 4lb cap.
 
The radiator holds 22 quarts. I have been told that you should just fill the 40 radiator so you cover the top of the core to allow for expansion of the coolant. Otherwise it will overflow. Try a 7 pound cap, instead of the original 4.
 
Does your radiator have the overflow tube coming from the top center . If its a stock 40 radiator it won't build any pressure regardless of the cap rating. What I did was had the radiator shop to solder the overflow shut where it comes out of the top then put a tee in the overflow tube at the filler neck. You will have to drill a hole in the filler neck for the tee and solder it in there . Now I can run a pressure cap and it looks stock, the tee that was added is hardly noticeable.
 
So, when it starts to overflow, it creates a 'siphoning' effect and takes more out? Thanks 19Forty; I will try that.

Ken, I am not sure I understand what you have described?

Thanks guys for your input................ Regards, Daryl
 
The coolant is going out the over flow tube. You have a 22 quart system which is designed to work with 22 quarts in the system not 17 or 18 which is what you have with the water down near the radiator tubes. There are three things critical to the cooling of these engines, amount of water in the system, the amount of water flowing through the radiator and system and the amount of air moving through the radiator. We can control the amount water in the system by keeping it filled with a WORKING 4 lb pressure cap or Skips 3 lb pressure valve that fits on the bottom end of the over flow tube. The cap or valve has nothing to do with raiseing the boilng point of the coolant the only purpose is to close the over flow tube to force coolant through the radiator and to act as a safety valve in the event of over heating releasing excessive pressure to prevent damage. The cap or valve allows the radiator to be filled up to the neck and stays filled for months with NO LOSE of water. If there is a compression leak in the engine this will cause excessive pressure in the system and the cap or valve will open from this pressure and allow water to excape. The BIG PROBLEM IS 90% of the pressure caps DO NOT seat down on the washer like seat about 1" down in the neck and allow water to excape. A rubber washer about 1/8th inch thick held with silicon down on the bottom washer seat after it is cleaned good over comes this problem or a proper fitting cap. The bottom end of the pressure cap must hit on the washer seat before the bottom of the top part of the cap hits the top of the filler neck. This takes care of the first part, keeping the system filled wit 22 quarts of water or coolant.
The second part is the amount of coolant pumped through the SYSTEMS. I say systems because the two sides of the block are seperate cooling systems, each with it's own pump. The only connection between the two is when the water or coolant is in the radiator. The amount of water pumped through each side of the engine is the key to the second part of cooling. If one pump pumps more coolant through it's side of the system that side will run cooler than than the other side where less coolant is being pumped. I have seen close to 25 degrees differance do to pumps where on a 36 type engine the pumps were swopped and the better cooling went with the pump that pumped more water. This is why it is important to test the temperatures on the head hose outlet on 37 to 48, the goose necks on 49 to 53 and the buldge on the behind the pumps on 32 to 36 and not in the radiator. The more water through the engine part 2 can be improved with pumps that deliver more water. Skip modifies all flathead pumps to greatly improve cooling with more flow. Every pump he does is tested on a water pump test machine and produces the following results against stock Ford pumps. 32 to 36 stock 55 gallons in 5 minutes, Skips 92 gallons. 37 to 53 stock 65 and skips 110 gallons. Along with more water with the more positive pumping action much less air is pumped. Straight water cools better than a milkshake of water and a lot of air due to the impellers slipping.
Part 3, air through the radiator is the hard part of the problem due to the poor fans on most old Fords. As long as the car is moveing 20 MPH cooling is not a problem. At idle and heavy traffic on days over 80 getting up near the 200 degree range can be a problem. The best course of action is to get moveing and in 1/2 mile the forward motion of the car forces air through the radiator and brings the temperature back in the normal position which is near the center of the gauge. 175 to 182 is the operating temperature my 2 39s operate at best being consistant in the way they run at all times. These cars ran a little to cool most of the time and way to cool on cool days. I installed Bob Shewmans gadgiteer@aol.com 180 degree thermostats in both 39s and from 50 degrees to 92 both sides of the engine are 178 to 182 every time I check them. Bobs stats are heavy duty with large flow openings that do not restrict the flow like most others. These stats mount in the hoses and don't need clamps to hold them in place, All year Fords do not operate the same as far as cooling do to fan location, size and number of blades. Cooling is also affected by the way air is directed through the radiator and the venting of hot air trapped in the rear of the engine compartment. The crankshaft mounted fans to me are the biggest problem. Shrowds and better fan blades provide better cooling but not many blades are available and shrowds can be hard to install on some years. G.M.
 
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Ken Is correct if the over flow comes off the top of the tank you need to modify the neck as he suggested but the washer seat must be down about 1" in the neck or that won't work. Or Skips valve can be installed. G.M.
 
Thank you all for your time and input. I have copied Skip's ad from V-8 Times magazine and will order this week. From my experience, your input, it appears this might be my solution. I will share information after install.

Thanks again, Daryl
 
Hi, Just wanted to let those know, who might be interested, that I did get the Skip Haney valve for the overflow tube and it works like a charm..............

Thanks again everyone for your help.

Daryl
 
You don't need Skips valve if the over flow tube is in the neck of the radiator. If the over flow tube comes out of the neck and you stiil lose water it's either the bottom of the pressure cap don't quite reach the washer like seat about an inch down in the neck or higher pressure in the radiator from a compression leak. Or you may not have a pressure cap. Either a plain cap or 4 lb will fit on the 39-40 radiators. It's strange but most pressure caps I have seen are a little short and require a rubber washer down on the seat in the neck. If the bottom of the pressure cap don't hit before the top of the cap hits the top of the neck you don't have a working pressure cap. It is only a plain cap. G.M.
 
Skip has adds in the V/8 Times the Early Ford V/8 Clubs by/monthly magazine. Attached is Skips valve literature which has his contact info. G.M.
 

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Dumb question I guess, but how do you test the temp on the head hose outlet on a 47. Is there some sort of fitting that you can put on each hose and read the temp from the drivers seat???
 
Go to Radio Shack and purchase their hand operated temperature gauge. It is very useful for a lot of things................
 
I just happened to come across the attached picture. My 39 had the overflow off the top of the radiator. I cut it off up at the top and plugged it. Drilled a hole in the side of the neck and soldered a copper tube for the new over flow. This radiator had the bottom seat down in the neck but used a plain non pressure type cap. Most pressure caps as I mentioned don't seat down on the bottom seat this shows the red rubber gasket material I put down on the seat so the pressure cap hits it and seals to make the pressure cap work. Also notice as I have mentioned many times on past posts how clean and polished the top plate and tubes are. This is a 25 year old core that is polished internaly by Skips high volumn pumps forceing heavy duty Barrs leak sealer with aluminum granules though the system for a long period of time. This don't happen over night but is brighter and cleaner than any new radiator. I imagine it cleaned the internal length of the tubes and must have some effect on the inside of the engine. The engine runs at 180 all the time with gadgiteer@aol.com 180 stats in the upper hoses at 95 degrees outside temperatures while driving. G.M.
 

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