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Solving Oil Foam Under the Filler Cap
I have been using Mobil 1 for the last 5 years in my SUV. For the last year I have been experiencing oil foam under the filler cap. Is there any fix?
-- Paul Asfazadour, Middlevillage, NY
Visible foam is an unusual issue. All motor oil comes with anti-foam performance. Are you sure you are seeing foam or is it like a mayonnaise-like consistency which may indicate that you could have a coolant leak? Send your oil to a lab for analysis and have it checked for glycol in the oil. You can get a test kit at some auto parts chains.