Foaming/cavitating coolant in my 34

[37 Coupe]

Sorry,don't know why I try to post what I have experienced among the experts.

[Seth Swoboda]

I think we have all given good ideas as to what may be causing the problem. I very recently had this problem on an 8ba engine with aluminum Offenhauser heads. I found out that do to my neglect to recheck head torque there was a compression leak. Improperly torqued heads caused the overheating issue. I pulled the heads, had a machine shop lightly clean the head surface. I cleaned the deck of the engine, bought new studs and head gaskets and reassembled. I re-torqued the heads through 4 heat cycles to 45 lbs. So far no overheating. My mechanical temperature gauge says I'm running 180 degrees tops. So far so good. It was an expensive lesson that I learned the hard way. I re-torqued the heads on my other flatheads (all stock with cast iron heads) just for piece of mind. Anyway, this has been my experience with a similar problem. This is what I did to remedy the situation. All other suggestions are relevant and worth checking into also.

[Mark's 37]

I haven't done this with a flathead but did these tests for many years as a Ford mechanic. If there are combustion gases in the cooling system from either a leaking head gasket or a crack somewhere these 3 ways of testing work well.

1. Install a radiator pressure tester on the radiator and watch the pressure gauge while running the engine at idle and at fast idle. If the pressure gauge needle begins to climb, pressure from cylinder compression is leaking into the cooling system.

2. I have used this tool many times. Follow the instructions carefully. Lower the coolant level enough to be sure the coolant isn't sucked into the fluid chamber of the tester. If the tester fluid changes color according to the instructions, there are combustion gases in the cooling system.
http://www.summitracing.com/parts/oe...7XcaAstW8P8HAQ

3. The easiest way, if you have access to a Smog Test machine, is to again lower coolant level a few inches and with the engine running at operating temperature, check the CO/HC level with the Smog Machine probe sitting just inside the radiator without touching the coolant. If CO/HC level goes up, same thing, combustion gases in the cooling system.

[Dave D]

You need Skips 3 lb valve to keep the water in the radiator.

Don't do that! I had one of his valves, it seized close within a month and damaged my radiator. The valves he use do not appear to be for fluid use, more like a vacuum valve.

I had (have) the same problem as you, with the stock 4:11 gearing anytime I got over 55 MPH it pumped water out of the radiator overflow. A Columbia rear solved that one! I should mention I have Skips pumps, don't know if would happen with stock but Skip said his '35 pumps flow no more than the stock ones.

[flatheadmurre]

Before ripping everything apart.
The antifreeze contains antifoaming has it been used up for any reason ?
So check it for exhaust/oil leftovers.
Sucking in air in a non pressurized system is possible adding a low pressure to the system will take that out of the equation.
Antifreeze has additives that is used up how fast depends on the enviroment its in.
If it was me i should have the coolant checked first and then start hunting down the fault source.

[G.M.]

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Originally Posted by Dave D

Don't do that! I had one of his valves, it seized close within a month and damaged my radiator. The valves he use do not appear to be for fluid use, more like a vacuum valve.

I had (have) the same problem as you, with the stock 4:11 gearing anytime I got over 55 MPH it pumped water out of the radiator overflow. A Columbia rear solved that one! I should mention I have Skips pumps, don't know if would happen with stock but Skip said his '35 pumps flow no more than the stock ones.

The instructions tell you to rinse the valve at least once a year. If your system is extremely dirty as it appears yours was it needs an extensive flushing. There are
1,000's of Skips valves in use with very good results. The high flow pumps would
tend to recirculate dirt more than stock or other after market pumps because of
the volume of water going through the system. A real good flushing will get rid of
most of the dirt. I think you misunderstood what Skip said. On his water pump test machine 32 to 36 stock pumps deliver 55 gallons each in 5 minutes. Everyone of his modified 32 to 36 pumps are tested and deliver 92 gallons. Stock 37 to 48 pumps
deliver 65 gallons in 5 minutes and everyone of his modified pumps deliver 110
gallons. You might question how every pump delivers the same amount. This is
due to machining of the pump bodies, the improved impellers that are assembled
within clearances of several thousands of an inch. Skip does not rush just to get
pumps shipped, he realizes that it is expensive and loss of time to resolve problems.
I told him when he started rebuilding coils that you could do 1,000 good ones and
nobody hears about them but do one bad one and the world hears about that one.
I think the results of his work over the past 20 years speaks for his work. And by
the way the 3 lb valve is made with a SS spring and all brass parts made to
operate in water. These are manufactured by Skip, not a purchased part. G.M.

[Dave D]

My motor was a brand new rebuild and the entire cooling system was clean, the valve failed plain and simple. As for flushing the valve yearly, it's way too big a price to pay if that valve sticks prematurely as it will almost certainly ruin your radiator when it pressurizes WAY over it's design limits.

As for the pump flow Skip himself told me the '35-36 flowed no more than stock, his later pumps had better impellers. If they are flowing more I may remove them to keep from pumping fluid out of the filler neck at speed.

By the way, at just what RPM are you getting those claimed flow rates?

[G.M.]

Originally Posted by Dave D

My motor was a brand new rebuild and the entire cooling system was clean, the valve failed plain and simple. As for flushing the valve yearly, it's way too big a price to pay if that valve sticks prematurely as it will almost certainly ruin your radiator when it pressurizes WAY over it's design limits.

As for the pump flow Skip himself told me the '35-36 flowed no more than stock, his later pumps had better impellers. If they are flowing more I may remove them to keep from pumping fluid out of the filler neck at speed.

By the way, at just what RPM are you getting those claimed flow rates?

I am sure Skip didn't tell you that, call him to verify that. The stock pumps and his pumps have a variable output depending on speed. At about 2,800 RPM's his 36 pumps put out 92 gallons in 5 minutes and at 1,400 exactly half at 46 gallons. G.M.

[FlatheadTed]

This is what I use of a 50s car ,its a two way valve and it will suck back .You can fit a 41b cap on it .It changes it into a closed system were you can force more water through ,Ted

[Scott754]

I've read through all the posts in this thread, and with a somewhat similar problem, many of the points here are helpful. I have a 35 Fordor with overflow tube off the top of the radiator. I purchased this car during this summer and drove it frequently in 80-90 degree temps with no real problems (in stop and go traffic the temp gauge would climb to the top but no boiling over or other issues). Recently I've started getting white foam coming out through the overflow tube, although the temp gauge shows normal with no overheating. I have put distilled water in since I owned it. I assumed antifreeze would raise the boiling point, so I put in approx 3/4 gallon (assuming that would give it approx 50-50 mix). I've driven it approx 60 miles since, and still was getting the foaming. Not sure from the above thread what the conclusion or recommended next steps are. I keep this car in a heated garage, so freezing isn't a concern; does antifreeze cause problems and is the advice to get it out of my car? I don't have a drain plug at the bottom of my radiator (that I have found) so not sure how best to remove the antifreeze? thanks

[flatjack9]

I have the same problem with my 39. It has an original radiator with the overflow off of the top tank. It will foam and spill out the overflow with an antifreeze mix. Plain water - no problem.

[Scott754]

Originally Posted by flatjack9

I have the same problem with my 39. It has an original radiator with the overflow off of the top tank. It will foam and spill out the overflow with an antifreeze mix. Plain water - no problem.

Is there an effective way to drain the antifreeze out of the radiator to replace it with distilled water?

[Steve Staysko]

You have drain cocks on each side at the bottom front of the block just open the drain valves.

[BrianCT]

Originally Posted by Scott754

I've read through all the posts in this thread, and with a somewhat similar problem, many of the points here are helpful. I have a 35 Fordor with overflow tube off the top of the radiator. I purchased this car during this summer and drove it frequently in 80-90 degree temps with no real problems (in stop and go traffic the temp gauge would climb to the top but no boiling over or other issues). Recently I've started getting white foam coming out through the overflow tube, although the temp gauge shows normal with no overheating. I have put distilled water in since I owned it. I assumed antifreeze would raise the boiling point, so I put in approx 3/4 gallon (assuming that would give it approx 50-50 mix). I've driven it approx 60 miles since, and still was getting the foaming. Not sure from the above thread what the conclusion or recommended next steps are. I keep this car in a heated garage, so freezing isn't a concern; does antifreeze cause problems and is the advice to get it out of my car? I don't have a drain plug at the bottom of my radiator (that I have found) so not sure how best to remove the antifreeze? thanks

3/4 gallon would only be about a 20/80 mix.