Why is there a white film on my oil cap?
In most cases the white stuff is moisture. Determining how the moisture got into the engine; will tell you whether this is nothing to worry about or if it’s something more serious. Causes can range from, condensation from weather changes to a blown head gasket.
Does a milky oil cap but not dipstick?
The discoloration likely represents the effects of entrained moisture in the oil on the cap surface. There can normally be a certain amount of condensation in an engine, for example as weather conditions change or if the engine sits for a while unused.
What does it mean when your oil looks milky?
If you take a look under your engine oil cap and notice a milky-brown substance roughly the consistency of a milkshake, that could indicate a major engine problem. Or, it could indicate nothing unusual at all. The most common cause of this is a coolant leak somewhere in the engine causing coolant to mix with the oil.
What to do about White Stuff under the oil cap?
When this happens, you are increasing the risk of forming a frothy sludge under the oil cap. If the engine bay requires cleaning, it is best to use low-pressure water spray. It is also important to avoid spraying engine seals such as those found in the valve cover.
What happens when you take off the oil cap?
So, you take the oil cap off of your valve cover to top off your oil. You find a milky creamy white stuff, coating the underside of the oil cap and down into the filler hole. So, what is this white stuff and what is it doing in my oil system?
Is it normal to have yellow gunk at the oil cap?
As long as you have checked the dipstick and have done a quick check of the valve cover inside comes out when it is clean, you will be in a position to eliminate any problem with the engine. So the yellow gunk should not be a cause of alarm as it is very normal after a short trip driving.
Why is there a milky residue at the oil cap?
It is the one which forms a tight seal between the cylinders of the engine and the block of the engine. It makes sure that there is maximum compression for the engine to run in a manner which is smooth. Its other important function is to prevent the engine oil or coolant from making its way to the cylinders.