My sisters passat has a milky gunk on the oil cap. I see it in the crankcase a little too, her previous car, was an 02 wj with that dreadful 4.7 v8. The water pump went and she blew the head gasket on it! Guess who got stuck fixing that? The thing ran better than before after doing the head gaskets, then a few months later, she decides she wants a smaller car! My mom was looking for a new car, so my sister bought my moms 06 passat, and my mom got a 2013 cc. I feel crazy telling that whole story. But the point is, I'm paranoid with head gaskets now, so how's that oil look? It's whiter in person, it looks muddy and brown in the picture. Lmk what you think.

 

Is it just on the inside of the cap or is it on the dipstick when you check the oil? In the winter, you get more condensation then in warmer weather. If you drive a bunch of short trips, it doesn't let the engine get warm enough to evaporate it. So, it'll build up a little. Are you loosing any coolant from the system? The exhaust puts out more "steam" in cooler weather but is yours putting out an abnormal amount? Check your oil. Drain a little out if you have to. Also, you could pressure test your cooling system.

 

if you let the vehicle sit overnight and loosen the drain plug on the pan look for water coming out. oil floats. this will tell you everything you need to know.










if there is no water it is most likely just condensation. the above information is accurate regarding short trips, etc.

 

If you want to know for sure just compression test it.

 

About the coolest pressure test I've ever seen done on an engine involved pressurizing each cylinder with an air hose. Bring each cylinder to TDC (and it's got to be at TDC or it will flip over when you pressurize) and screw in an air hose adapter into the spark plug hole. Listen in the oil filler hole. If you hear air leaking, it got bad or weak rings. Listen in the throttle body, shows leaking intake valves. Likewise exhaust valves show in the tailpipe. Bubbles in the radiator is obviously a cracked head or blown head gasket. It's time consuming, but it's the best engine test I've ever seen.

 

The guy I work with has an 06 passout. He had to pull the head because the timing belt broke. The head bolts have to be replaced and requires a special socket. If you want to do the timing belt you will have to remove the front end of the car. No joke.