yellowish white film on the oil fill cap and in the oil fill tube
 

ok so i been running full syn oil for about a year now about a month ago i added new syn oil and the oil fill cap and tube were clean. i checked it today and there was a yellish withe film on the under side of the oil fill cap and i nthe oil fill tube any one have any idea how this is happening. also my car is burning oil and i dont no y

That type of film is often associtaed with H2O contamination.

Doesn't sound good.
Take a look at your coolant and see if there's any sign of oil in it. Look in the radiator, not just the overflow jug.
Coolant should be a translucent color. Any cloudy,yellow or brownish coolant is a sign of oil present in the coolant.

Do you take a lot of short trips with your HHR? I ask because this could just be condensation that forms as a resuls of many short trips with the vehicle. This can happen because short trips don't allow the oil is to get hot enough to evaporate the moisture contained inside the engine. The handful of times that I've seen this it has been on higher mileage cars (well over 100K) that were running full synthetic oil where that wasn't a manufacturer requirement. Synthetic oil dissapates heat better than convenitonal and thus takes longer to warm up.

Very true. I remember that my air cooled VW's were prone to this, especially since most of us used them for station cars back in the day. Never found the residue under the valve covers while adjusting valve lash, but always under the oil filler cap, which was the highest point.

"also my car is burning oil and i dont no y"

To determine where on this, I would suggest you have a "Leak-Down" test performed.. This will determine if you are leaking oil past piston rings, OR Valves.

Agree with db/sb & 87silver-

I would however also pull the dipstick to check what the oil looks like on it..

The posts about condensation are correct. Used to get that in the filler tube of our 1987 Porsche Turbo, mostly when we made short trips a lot.

When you said the engine is "burning oil" what do you mean? Is it smoking, dip stick just dropping too fast, leaking and you don't see it, or ???? If it is going into the exhaust then the cat is going to be killed shortly so you want to find where it is going quickly and the compression test/leak down test are needed.