Foaming coolant

[rhschwerdt]

Is foaming coolant (about 50/50 anti-freeze/distilled water) an indication of a blown head gasket?

[BRENT in 10-uh-C]

Typically. It could also be a crack in the head or block where combustion gasses are entering the coolant.

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[TMarsh]

I had foaming after 10 miles at 50 MPH. Looked like whipped cream. Made me sick. No overheating indicated. Had cheap antifreeze, tap water, and off brand stop leak. Drained it all put in 50/50 Prestone, distilled water. No problem since. I suspect it was a mixture of what I put in the radiator that just got whipped into a foam, went all over the windshield and hood. Stopped and put 1/2 gallon of water in and continued 35 mile trip. No problem since.
Just my personal experience.
Hope you discover something as simple.

[Bob Bidonde]

Foaming is an indication that the water pump is mixing air into the coolant. This may be the result of:
>Coolant type or additive;
>Restriction in the coolant inlet route to the pump.
In many cases a thermostat in the coolant outlet hose to the radiator solves the problem. Another cure is run a stock radiator cap instead of a flip-top cap.

[ryanheacox]

Yep. The air getting whipped into the system is likely combustion gas leaking past the head gasket. Any idea which head gasket your engine has on it?

[Bruce_MO]

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Simple test... fill the radiator to the top. Disconnect the fan belt so the water pump won't turn. Start the engine and look for bubbles at the filler neck. Any bubbles are an indication of a blown gasket or crack as Brent points out. Don't do it too long; she'll get hot pretty quick.

[Chuck Sea/Tac]

Originally Posted by Bruce_MO

Simple test... fill the radiator to the top. Disconnect the fan belt so the water pump won't turn. Start the engine and look for bubbles at the filler neck. Any bubbles are an indication of a blown gasket or crack as Brent points out. Don't do it too long; she'll get hot pretty quick.

Does it really matter if the pumps not turning? Seems like you would get bubbles either way?

[Bruce_MO]

Stopping the water pump from turning reduces the chance of what Bob pointed out... air leaking in as the source of the foaming.


What you should see is nice big bubbles coming to the surface, especially when you speed up the engine a bit and create more pressure leaking thru the defective gasket surface.

[rhschwerdt]

Thanks to all. I'm pretty sure it's a blown head gasket or crack in the block or head. I'll try a couple of these tests and see what happens.

[daren007]

A leak down test will tell you everything you need to know.

[The Master Cylinder]

Originally Posted by rhschwerdt

Thanks to all. I'm pretty sure it's a blown head gasket or crack in the block or head. I'll try a couple of these tests and see what happens.

A lot of good suggestions. The first thing I would do before tearing it all apart is re-torque the head. It may prevent a lot of heartburn. Then proceed from there. Good luck.

[30 Closed Cab PU]

An alternate test for exhaust gas in the coolant - Block Test Kit, tests the air in the upper radiator tank for exhaust gas. Can easily do yourself, or check around at radiator shop or your local independent shops. Usually cheaper on amazon.



https://www.napaonline.com/en/p/BK_7001006

[ryanheacox]

Originally Posted by 30 Closed Cab PU

An alternate test for exhaust gas in the coolant - Block Test Kit, tests the air in the upper radiator tank for exhaust gas. Can easily do yourself, or check around at radiator shop or your local independent shops. Usually cheaper on amazon.



https://www.napaonline.com/en/p/BK_7001006

That's the kit I have. Here is what a slight leak looks like, a bad leak should turn the fluid yellow.