AMk617

I just replaced the spark plugs on my 2005 C240 4MATIC & repaired the valve cover gasket with the rtv compound. When starting the engine up it was shaking and smoke/burning smell was coming from the left side.


Help please!!

Plutoe

Make sure all your spark plug wires are firmly seated----and be a big boy and replace the valve cover gasket rather than using a cheapo chewing gum!!

PS:If you had the shaking before and assumed new plugs would solve your problem you may be wrong---so tell us the real story!!

AMk617

Thanks, I appreciate your response.

The vibration was not present prior to maintaince.

I replaced all 12 plugs, serpentine belt & valve cover gasket. Upon completion I started the engine & it looked as if there was smoke coming from the right side of the cylinder where the boot connects to the plug ( I believe the wire to plug connections were lose). I removed all 12 plugs again, gave the spark plug holes a more through clean. installed plugs back in & made sure the wires were secure on the plugs.

When I stared the engine again the engine wasn't viibratin as rough as before but it's still rough.

dstacy99

Sounds like you did not tighten the plugs to specs

insame1

what are you using to clean the holes?

AMk617

dstacy99, that potentially being the issue has definitely crossed my mind. In the event that I had no torque wrench on hand I used a standard wrench to do the tightening.

insame1, I used a thread chaser & a rag that I rolled up to fit in there.

Any suggestions/tips in regard to correctly tightening with a standard socket wrench or any additional info that applies to the issue in general would be greatly appreciated.

insame1

every time I have done mine by hand I bring them up snug then do about another full turn. They have crush washer on them so you need to apply a little more force than you think. I WOULD STRONGLY SUGGEST GETTING A TORQUE WRENCH THOUGH. a striped hole or broken plug will cost much more.

Also did you check the gap. they "should" come gaped but who knows.