Foaming coolant 34 3W

[Keystone 34 3w]

Driving 60mph creates no problem, but if I push 70-75 still no problem until I slow down and then the Greyhound cap can't keep the foamed coolant from spraying down the hood and windshield. Head gaskets were replaced and even both aluminum heads. Water pumps have the four straight blade set-up, heads planned and torqued to 50lbs with fiber gaskets and copper-coat. Coolant is green Motorcraft 50/50 mix. I ran with and without 170 thermostats, no change. Engine temp reaches about 180 and coolant does not boil. My question; does anybody run their 34 at 70-75 without my problem and what can be causing the foaming?

[Brian]

This is obviously a water pump in head 21 stud engine- right? This is a characteristic of these engines. I regularly drive my 35 with similar engine at same speed range. What happens is that the pumps are pushing hot coolant up into the top tank, Ford addressed this issue in 37 by relocating the pumps so they draw cool water into the block. This isn't solving your dilemma though- is it?
The problem is in the radiator design. Because coolant is blowing outta the cap demonstrates that the cap isn't sealing/ cannot pass the coolant quickly enough through the overflow tube. First step is to ensure the radiator cap actually seals. Then, run the overflow into a catchcan, much like a modern car has, this must be able to allow the radiator to syphon coolant back. At high engine speeds the coolant temp goes up; expands through the overflow [not outta the cap], but upon slowing down the coolant also cools, this creates a vacuum and the radiator will draw coolant back from the catchcan, always maintaining a completely full system. All modern pressurised systems operate like this, although our old Fords don't have 'pressure caps', if we can acheive a proper radiator cap seal in conjunction with the catchcan, then we can drive our cars in modern traffic, no worries. I do. Brian

[G.M.]

Not quite how it works Brian. Also the pumps being moved to the block make no differance. There are 3 problems. The cap doesn't seal and needs a new red rubber gasket installed by drilling out the rivet and replaceing the seal and held back together with a 1/4-20 SS screw, lock washer and nut. The hoses dump 4 1/2 square inches of water into the top tank, the 144 radiator tubes add up to 3 1/2 square inches this along with the length of the tubes and dirt in them restrict the flow even more. This is like putting 4 1/2 pounds of poop in a 3 1/2 pound bag. So the excess coolant runs out the UNRESTRICTED over flow tube until "it finds it's own level" as the statement went for 70 plus years. Now at "it's own level" the system is now a gallon low on water, being 18 to 20% low on coolant this causes the engine to run at elevated temperatures, this is a 22 quart system not 18. This is where the use of washers or restrictors came in the picture. With the restictors the water was slowed down going into the top tank, water was still lost out the over flow but not quite as much and now it didn't boil over but ran up in the 190 to 200 range. These engines should run in the normal range on the gauge. You don't want any restrictions such as modern stats or it slows the flow and makes the engine run hotter, stats only heat an engine not cool them. In the early 40s the over flow was brought out of the filler neck and a 4 lb pressure cap was installed. This was not to pressurize the system or raise the boiling point but to keep the water from going out the over flow. If the coolant don't get over 205 there is only about 2 lbs pressure. If the water comes out the over flow under 205 degrees with a 3 or 4 lb pressure cap or valve on the over flow the cap isn't sealing and working or there is a compression leak in the engine puttting pressure in the cooling system and opening the cap or valve. In this case the cap or valve is acting like a safty valve relieving the pressure so the radiator or hoses don't blow out. The coolant in the old Fords does not expand very much below 205 degrees, the long large diameter hoses will allow for this small amount of expandtion. This allows the coolant to be filled up to the top of the filler neck and never lose any coolant in months of hot weather driving. I drove 1150 miles last week in my 39 with Skips pumps and a 4 lb pressure cap,it was between 100 and 110 out side temp for 2 twelve hour days of driving at 65 to 70 MPH. I got in a 6 or 8 mile traffic jamb for 20 or 30 minutes and it went up over 200 and cooled down as soon as I got moving to about 180 which it held for most of the trip. I removed the cap the next morning after the first day and water came over the neck. Also removed it the day after the second day and it still came over the neck. I might add I have 2 gallons of prestone, 2 bottles of Water Wetter and a large bottle of Barrs heavy duty aluminum granular sealer in the system. Keystone your stock 32 to 36 pumps deliver 55 gallons each in 5 minutes, Skips modified pumps do 92 gallons. More coolant, more water flowing through the system equals better cooling and with the system full of coolant there is no air stirred in to make foam. Pure coolant with no air cools better than coolant with air mixed in it. Click on my web site below for info and email Skip if you have any questions. G.M.

[Brian]

GM, by running the overflow into a catchcan, and ensuring the stock [non-pressurised] cap seals correctly, means the radiator is alsways full to the brim, hot or cold. I don't want to get into a disagreement with you, but all I know is what works for me, and I offered my experience to keystone. I run a full race 21 stud engine at high speed regularly [because that's where it's happiest] and have overcome the coolant coming outta the radiator issue. So mate, this is exactly how it works. Brian

[flatjack9]

Keystone, try running water only with an anti-rust compound in and see if that makes a difference. Years ago I had the same problem with my 39. Drove me nuts. I observed that the anti-freeze would form a foam in an unpressurised radiator. I put a glass tube in my upper hose and watched the formation which would then bubble out the overflow. So I tried just the water and it hasn't caused me a problem in 15 years. I have a stock non pressurised radiator.

[FL&WVMIKE]

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Keystone 34 3w .........................
Like Brian said, your radiator cap is not sealing under the extra pressure.
I used to have two radiator caps, One for "go" and one for "show". The "show" one would leak, like you described. The "go" one would not leak, but was an old original one and didn't look so hot. I finally made a new gasket for my "show" one.
MIKE

[rick r]

the foaming is probably caused by the water pumps sucking in air around the pump seals when the engine is running. had the same problem with my 8ba. nearly drove me crazy for most of a summer. the most respected flathead geru in ontario was the one that clued me in. rebuilt the pumps with job lot kits and immediately solved the problem. have posted this info on fordbarn in the past and had several members tell me that i am crazy. could be, but it solved my problem. if you want more info, give me a call at 705 439 2567

[G.M.]

Rick the pump didn't suck air around the pump seals. The cooling system has some pressure and it couldn't suck air. Something else that happened like the cap sealing better fixed your problem. G.M.

[G.M.]

Brian when the coolant is in a "catchcan" it is NOT in the radiator and does not help in cooling. This water in the can makes room for air and foaming. The hot water in the can stays there until the engine starts to cool and at 155 degrees the small check valve on the bottom of the pressure cap opens and the coolant thermosyphons back into the radiator. With the engine running below 205, the coolant FILLED TO THE TOP OF NECK there is not lose of coolant, it stays filled and there is no room for air as long as theer is not a compression leak. G.M.

[Brian]

GM,
when the coolant is in a "catchcan" it is NOT in the radiator and does not help in cooling.

The spillage that goes outta the overflow due to thermal expansion, and is normally lost, is contained in the catchcan- this ensures the radiator is always full to the brim. As the overflow tube runs all the way into the liquid contained within the can, as the coolant cools [shrinks], the coolant syphons back into the radiator, therefore constantly maintaining a full system.
'and at 155 degrees the small check valve on the bottom of the pressure cap opens and the coolant thermosyphons back into the radiator.'

A 34 Ford does not have a pressure cap. However, if one can get the cap to seal [and one must in order for this system to work], then it does allow for a bit of pressurisation/depressurisation to take place.Then the only path available for the 'excess' coolant to take is through the overflow tube.
All we are doing is maintaining a totally full radiator; I'm doing it my way, and your technique involves using a pressure valve on the overflow. Different methods toward the same goal. One thing to bear in mind is the large top tank on an early Ford. Don't want to apply too much pressure to one of them. Brian

[rick r]

to G M, as i said several fordbarn members have told me i am crazy, but it was the reduilt pumps that solved the problem, not a better sealing cap. give it some thought. the inlet side of the pump is sucking coolant into the vanes so it can also suck air in around a slightly worn seal. takes very little air to make anti freeze foam like warm beer. if you want to solve the problem, rebuild the pumps. at $25 a kit, it is worth a try.

[G.M.]

I don't have to think about it, we have rebuilt thousands of sets of early Ford pumps. They can not suck air and don't get slightly worn seals. If a seal is bad it leaks water, to suck air the suction pressure would have to be higher then the pressure in the system. You had another problem that was cured when the pumps were off. G.M.

[FlatheadTed]

The need for a pressurized system is because of a blocked or under sized Radiator .My 34 Radiator cap always threw water when pushed hard I made several attempts to seal it ,then the temperature would rise ,because of shortage of water ,I not saying it not a good idea to have some back pressure ,The stock pumps pump a lot of water but not so much at idle .

[G.M.]

A better description would be a closed system with a safty relief valve. The closed system has no place for water to escape and forces the water through the radiator, again maybe 1 lb pressure is generated by the pumps and another lb by 200 degree water and the cap or valve is only a safty valve incase of a compression leak or very high water temperature. The early caps can be sealed TIGHT with the red rubber gasket material found in the plumbing section of most hardware stores. In a closed system fill the radiator up into the neck. G.M.

[FL&WVMIKE]

Keystone 34 3W ...........................
Another thing - If you ever ran detergent through your radiator and didn't SUPER-RINSE it out, you will get foam. It won't come out your radiator cap, if you have a good seal. But, it will still come out the overflow.
I can tell you from first hand experience ! LOL
MIKE

[FlatheadTed]

As I said my 34 Radiator always pushed water ,It never got hot till I lost water ,Through over greasing the pumps over the years this had caused the temperature to clime , When i removed the top tank I noticed the stock tank showed the original amount of tubes,the replacement core that was fitted some years ago had about 29 short, Over here were the climate is mild this may not matter but if you lost 10% of them as i did then thats a problem . In a hot climate these 29 tubes would be needed for exstra cooling , Now that I v got the grease and rubber rust scale out it no longer throws water ,and runs cool ( it still has the 20 tubes short ),This shows that it was creating a partial vacuum .A little pressure offered by a catch can or by a pressure valve forces water through the closed system or a bigger Radiator would help .There was a 4" Radiator offered with a extra row of tubes in 1934,

[Keystone 34 3w]

Just got a bottle of water wetter from my dirt track vendor and filled the rad with well water . Went on a highway test drive at 60 mph no problem. Then tried 70 mph with no problem and pulled off to the side and took the Greyhound off and took a look inside the rad and saw my face reflecting in the clear water with no foam! I still don't believe it.Thanks for all the advice and discussions. I will follow recommendations on rebuilding the pumps with high flow impellers and new style seals since they do leak off the pulleys. Thanks to all.