I have a 2000 Ford Focus. Past 6 month I have been smelling oil in the car thru the vent after coming to a stop light. My mechanic is saying it could be a gasket leak on the block that burns off. There is no smoke of any kind. Any ideas.
When my wife had a valve cover gasket leak, we learned that it takes very little oil dripping to make a noticeable smell. We did eventually see some smoke by using a flashlight in the evening when it wasn’t too bright out. Also, in her case, the car had to be on a fairly steep incline for the drip to happen, so you might try parking in different directions on a hill when you look for smoke.
It could be a gasket leak.
I agree with your mechanic. He sees a known leak that could cause this. Fix that first. If the smell doesn’t go away, you have an additional leak problem.
I can add that a gunked-up PCV valve could be related to this problem. The increased pressure in the crankcase as a result of a gunked-up PCV can lead to leaks in old gaskets, and there could even be oil fumes emanating from the area of the PCV itself, if it is clogged.
In view of how incredibly cheap a PCV valve is, I would suggest starting by replacing that little part.
Check the oil pressure sending unit. I had the same symptoms with my 93 Caprice, the sending unit was slowly dripping oil onto the exhaust pipe causing the smell. The leak was so small there was no noticeable smoke.
Fix all the visible oil and transmission fluid leaks, and see if the problem goes away after a month or two. If it doesn’t, special UV dyes can be placed in the oil and transmission fluid to help find the remaining leaks.