When I check the Oil on my 250 chevy motor, I have been finding a coat of foam on the Oil Filler Cap, and sometimes on the dipstick.

I changed the oil last week and the oil still looks good.

The foam is just there when she is cold.
Lately in Arkansas we have had overnight lows in the 40's and 50's


250 Integrated Head / 1981 C-10 Pick up.