Foaming Coolant

H

HD Rider

Senior Member
Ok, you guessed it.
I'm having trouble with foaming coolant.
Drove about 25 miles Saturday to a nearby town for a little get together and some tacos. Some coolant leaked out looking like shaving cream.
Car is a 31 coup.
 
I had the same problem until I drained the Prestone and switched to Sierra antifreeze, 50/50 mix. No more foaming. Costs a tad more but it works.
 
Leaking head gasket or water pump seal can let air mix with the coolant. I use regular green antifreeze and never have foaming. Is it overheating?
 
Re-torque the head first, then see how it is. Like Tom said, I too use the regular antifreeze, 50/50. No problems.
 
Do the above. If still an issue, take the A to a Radiator or an Auto repair Shop and have a Block Test done for exhaust gas in your coolant. Or Napa has a Block Test Kit for around $50 and you can do it yourself, very easy to do.
 
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I would drain the antifreeze into a bucket, than add just plain water.

Drive it to see what you have. Drain the water into a bucket. What it looks like should tell you something.
 
I have seen foaming when using modern "long life" antifreeze. The antifreeze made for cars 1989 and older seems to work much better in Model A's. You can find it in most auto parts stores.
 
I'll retorque the head this weekend.
I wonder if adding a surfactant to the coolant would help. When I got home, the head was 176* at it's warmest point between spark plugs. It was not boiling over at any time.
 
Another thing, the radiator cap should be sealed. If its not add a rubber seal under it.
 
Tonight i retorqued the head nuts. The front two were a little loose. The rest were good.
I also added a surfactant to the coolant. The car is going on a 75 mile drive Saturday. I'll let you know how it goes.
 
Foaming used to be a frequent problem for me, on two different cars. This happened even when doubling up on the rubber radiator cap gasket and double-sealing it with Permetex silicone adhesive.

Ultimately, I found my causes to be, on different occasions:
a) Residual radiator flush cleaner in cooling system
b) Rust from engine block, lodging in radiator tubes, causing poor flow through radiator
c) Overheating, as a result of heat (100ºF outside temp), uphill driving, and a more mild amount of (b)
d) Suspected, but never proven, head gasket leakage, while using the 'Premium Head Gasket,' i.e. Snyders part no. B-6051-M (it seems there are clear, conflicting experiences on this gasket design)
e) Overheating as a result of coolant loss through radiator leak, preventing proper water pump operation and thus proper coolant circulation

Since switching to the 'Best' graphite gasket (i.e. Snyder's part no. B-6051-XO), and having my radiators cleaned in one case and re-cored in another, I have not had these problems.

-Andrew
 
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