Hi,

Hope your New Years are more free of car troubles than mine! I was driving my 1990 240 B23F, automatic transmission and heard a sound that I thought may have been a flat tire. After stopping, I discovered that a 2 inch diameter cap, at the back of the cylinder head and lined up with the cam, had popped off. It’s easy enough to replace the cap, but I’m trying to figure out why it popped off. I don’t think it just popped off due to age. Should I be worried about something else that caused high pressure under the valve cover? Perhaps the PCV system is blocked. Does anyone have any other ideas of what to check for that might have caused the high pressure?

Thanks for your suggestions!

Terry