running rough may need new valve covers
It’s possible. Check out this thread from BenzWorld.org: https://www.benzworld.org/threads/valve-cover-gasket-leak-causing-rough-idle.1571290/ Here’s the money quote:
leaks oil a bit,
running a little rough… been told need engine cleaned and new valve covers
Is oil running onto your spark plugs? If not, I think you need a new mechanic. (I presume he told you that you need valve cover GASKETS, not valve covers.)
Thank you, and yes, valve cover gaskets. Spark plug/oil issue not mentioned by this Auto center who also did smog cert. This vehicle has 237K + miles on it. My regular mechanic says oil leak is from transmission.
If your transmission has a dipstick, I would just monitor the fluid level. A ‘leak’, may or may not be significant. See how many miles it goes before needing a pint of fluid.
You don’t say, but I guess you passed your smog check, therefore CEL in off. The first thing to do about rough running is get a second opinion.
Thank you. We passed the smog test. Will try and monitor trans. fluid.
Does anyone have a reliable Mercedes mechanic in San Diego?
David , I don’t think there is a regular poster here that lives in San Diego who also has a Mercedes .
Besides one might be named that is too far away for you to use. That is why web rating sites exist . Actually a decent shop could probably help you .