What is this in my anti-freeze?
 

Just noticed this today after a short ride.

The foam is not oily.
The bubbles did NOT dissipate even after a few hours.

The dipstick was clean.
A few year back I did a LestOil shuffle in the cooling system but never had foam after that.

Thanks
Leo

Re: What is this in my anti-freeze?
 

Looks like something my dog throws up. Do you have a pressurized radiator? That may cause some foaming as the cap releases.

If you are not overheating then I would not worry too much about it.

Some anti freeze is more prone to foaming and some kinds of contaminates can cause foaming.

Re: What is this in my anti-freeze?
 

it looks like silicate drop out. Are you using the Anti freeze that is made for modern aluminum engines. they put in large amounts of silicates to prevent corrosion of the aluminum. Also, the pH of the antifreeze is about neutral. The old versions of antifreeze had very little Silicates and ran at a high pH. When Aluminum engines arrived, this antifreeze would corrode the aluminum( look at aluminum heads on an old flathead). The next answer was to drop the pH to slightly acidic levels. This saved the Aluminum, but corroded the cast iron. As a compromise, lots of silicates were added and pH was kept neutral. Some industrial antifreezes are low silicate and work well for our old engines. The other answer is to change the antifreeze often.

Re: What is this in my anti-freeze?
 

I do not have a pressurized radiator.



I'm using a low silicate formula. See the additional pic.
I'm not overheating.



Leo

Re: What is this in my anti-freeze?
 

Where did it come from, the over flow tube? if so maybe someone may a nest in the tube? I would drain, flush, refil.

Re: What is this in my anti-freeze?
 

It came from the overflow tube.

Re: What is this in my anti-freeze?
 

Wot's a LestOil shuffle?

Re: What is this in my anti-freeze?
 

Yes, please...inquiring minds want to know.

Re: What is this in my anti-freeze?
 

Ran for a while with diluted LestOil to flush out any oil and/or grease residue.

Re: What is this in my anti-freeze?
 

Years ago, I had a foaming problem, don't know why, running a good, standard-stock engine. I switched to "Sierra" antifreeze mixture, (50-50), in Model A and never had a foaming problem again. Note; I drive this Ford in all different temperatures, never boiled over, no vapor lock, etc..I keep the coolant level just under the baffle in radiator, where the truck seems to keep that level anyway, if it was overfilled.

Re: What is this in my anti-freeze?
 

Lestoil is a soap. It is likely that some small residual amount is causing the foam. Doesn't take much. As mentioned earlier, if not overheating, don't worry about it.

Re: What is this in my anti-freeze?
 

My 30' Town Sedan is doing the same thing after running Thermocure through it.

I removed the fan belt and ran the engine checking for bubbles in a slightly overfilled radiator. No bubbles were seen. When I replaced the fan belt the bubbles returned. Either there is residual Themocure left in the system causing the bubbles, or the water pump is developing them.

Tom L.

Re: What is this in my anti-freeze?
 

Long time learner on this site. We have had a '30 coupe for three years now and every problem that has come I have found the answer for here. The foaming anti-freeze has had me baffled ever since we have had the car. Two head gaskets plus surfacing the head and still the bubbles. Yesterday I drained the radiator and refilled it with a different brand and the bubbles are gone after a ten mile run home. Thanks every one for all the good info. Dale

Re: What is this in my anti-freeze?
 

I noticed your drip pan. Does it include the rear end?
Home made, or an east coast made pan?

Re: What is this in my anti-freeze?
 

Doesn't quite reach the rear.
To be completely honest, it's a cadaver tray.

Re: What is this in my anti-freeze?
 

If you put the antifreeze in a cup and stir with your finger and it foams don't use it. NaAPA sell and anti foam antifreeze