tranesq

Hi everyone,
I just purchased an 09 SL63 with only 28k miles from Carmax here in CA. We bought an extended warranty with it to be "safe", and only within days of driving it, problems started and were remedied. However, the engine SOMETIMES misfire ONCE in the morning with the check engine light on, sputters and then dies. I would start the engine again, and everything is perfect and normal and no check engine light. My scanner shows multiple misfires on the left bank of the engine. We took it to Carmax, who took it to a nearby Mercedes dealer. They erased the code, and "reset the MU" unit" and found no more misfire the next day. We took it home and drove another week, and now it misfired this morning again! Same thing. One misfire, and then everything is fine after that. I have changed all fo the spark plugs last week. Carmax verified that the coils are fine. Any opinions why this is happening? Also, if they can't find what's wrong with it, is it bad to keep driving? I do notice that the engine has that dreaded "tick tick" noise, but most prominent when cold. I would love your opinions. Thank you.

ItalianJoe1

Any coolant loss? That's within the range of the cars with the suspect head bolts.

Ticking is usually nothing more than noise, unless the car was poorly maintained and has a collapsed lifter.

tranesq

In the 1 month that I have had it, I do not see anything on the garage floor. Everything looks dry, and the coolant reservoir looks good.

okbarnett

Fortunately I had this engine and it was fantastic and I never had problems, BUT
other problems that you may have;
https://mbworld.org/forums/c63-amg-w...s-lifters.html
makes tap sounds.
But I would advise you to have CM turn this over to MB and not keep trying solutions, because they arent ever going to find it. Keep complaining and have them decide that you wont go away and they should have MB do the fixing

ItalianJoe1

Head bolt failure won't leak out, it will go into the engine and burn, and cause misfires at times.

Agreed though, if you have warranty, let benz fix it.

tranesq

Yes, Carmax actually drives the car over to the Mercedes Benz Dealer to have it looked at. Carmax won't touch it.....nonetheless, I can't believe the MB tech only erased the code tried it again the next morning without any further testing. According to the invoice, they charged Carmax $160 for that!