White Foam--Does Anything Other than Engine Oil Produce It?
 

I have some sort of a leak. Today's a very rainy day, and I noticed a white foamy substance on the driveway. Does this PROVE that it's an oil leak, or are there other fluids in the car that could react with water to form the white foam?

Thanks.

Windshield washer fluid will foam, oil will not. Trans fluid will repel rain water, the water will go around trans fluid. Power steering fluid same thing. So ck your washer fluid tank and hoses.

But it's an oily white sludge, of the same consistency that you'll see under an oil cap. That's why I was thinking it might be oil. Wiper fluid wouldn't be oily, would it?

washer fluid was an educated guess. If washer soap is in it then yes, it would feel oily.

It sounds like coolant mixing with oil, somehow, and how is it being expelled and from where? Headgasket failing and the substance described, being expelled under pressure from the coolant recovery system? Have you checked or added oil and coolant to your car lately? How much?

Have an expert take a look as it may require pressurization of the cooling system and or more. Don't let it go. Good Luck.

I had a coolant flush several weeks ago.

I'm with pastmaster. Looks like coolant mixed with oil. Check you oil and coolant levels and apperance. If those are mixed, It could be a cracked head, a head gasket, the oil cooler....

Oil Motor
 

YES it is most likely an oil leek (motor) it need not be very severe,an oil leek will spread like water soaking into paper,the least amount of dew will cause it to foam though it is not foaming it more closely resembles milk the thick milky looking gunk you might find on the oil stick if you had an internal water leek:laugh2: