I recently purchased a '98 C230 and have been satisfied with its performance over the past few months. Two days ago, I noticed a clicking sound when the heat is turned on, and only when the heat is on. Of course, I popped the hood and took a look at the engine and noticed nothing obvious or clear to the eye. This is when I noticed the major concern for this posting... I opened the oil cap to the engine, while the car was running, and to my despair found that air and oil were pushing the cap off. I did some research and concluded this to be a compression problem. Thus, I am wondering if this is a common problem? What could be the possible source or stem of the problem? What price am I looking at to get it fixed? Is it possible to fix on my own? Any information and suggestions would be greatly appreciated!! Thanks for your time...

Cheers,
Arun Ponnappan