Q. I’ve noticed a milky froth on the oil dipstick of my motorhome’s
engine. What is it?
A. Oil with a “milky” appearance is an indication of
the presence of water in the oil. Water contamination caused by condensation is a common
problem due to wide variations in temperatures. If the milky deposit is only on the inside
of the filler cap and/or top of the dipstick, it’s probably time to change the oil. If all
the oil is milky (if the oil on the bottom of the dipstick is frothy), it may be an
indication that there is a leaking head gasket or other component that is allowing coolant
into the oil. This must be corrected at once or severe engine damage will occur.