Smoke From Exhaust upon Third Consecutive Start Up. What Could Cause This?

[Sonny]

I have a question to which someone will hopefully have the answer.

My C63 was sitting for 8 days. I came home and started it and drove it around for about 15 minutes (it got up to operating temperature). Then I shut it off for the night. The next day I started it up (it was ideling), but within 2 minutes I had to turn it off (I didn't put it in drive). I then started it up again for another minute or so (but again did not put in drive, it was just ideling...I kept having to run back inside my house).

Finally, an hour later, I went to start my car and it made a louder than normal sound and smoke was coming out of my exhaust pipes and the smoke stunk pretty bad. The smoke came out of the exhaust for about 10 seconds. Then it went away and has not returned since. This has never happend to me before.

What do you think caused the bad-smelling smoke? I would really appreciate the feedback. Thank you.

[LZH]

Did the smoke have a blueish color to it ? If so that's oil. How many miles on the car and is it daily driven ? Could have been a small amount of oil getting past the rings during the multiple starts and collecting in the chambers - lots of different variables, very hard to tell. White smoke is water/coolant...I'd be more worried about that. Coolant is a sealed/pressurized system and you should never be burning that - if you do, you have a big problem. Check your coolant level when the car is hot.

[Sonny]

Did the smoke have a blueish color to it ? If so that's oil. How many miles on the car and is it daily driven ? Could have been a small amount of oil getting past the rings during the multiple starts and collecting in the chambers - lots of different variables, very hard to tell.

From what I could tell -- it was nighttime and not great lighting around -- the color was not blue. But, I didn't know that about the "oil getting past the rings during the multiple starts." Thank you for the feedback.

Do you think it's something to bring up to the dealer?

[LZH]

These motors are light years beyond good old American V-8's...I know people say the M156 burns a little oil, and that can be true, but they really shouldn't be burning anything. If your smoke wasn't blue I dunno man...hate to worry you too much, I'm sure it's not a big deal as long as the car is running normal, but when coolant is burnt it STINKS bad. Having said all that, I would say yes, I'd have your dealer take a look at it. But first, drive your car, get it up to temp, shut it off and then check your coolant level. You should NOT be losing ANY coolant. Good luck, keep us posted...

[Sonny]

Sorry, I forgot to answer two of your above questions. The car is pretty much daily driven but I was on vacation so it was sitting for about 8 days. And the car has 6600 miles on it.

[Sonny]

These motors are light years beyond good old American V-8's...I know people say the M156 burns a little oil, and that can be true, but they really shouldn't be burning anything. If your smoke wasn't blue I dunno man...hate to worry you too much, I'm sure it's not a big deal as long as the car is running normal, but when coolant is burnt it STINKS bad. Having said all that, I would say yes, I'd have your dealer take a look at it. But first, drive your car, get it up to temp, shut it off and then check your coolant level. You should NOT be losing ANY coolant. Good luck, keep us posted...

Thank you. I'll check the coolant. So far, it's been running like a champ since it happened, so I don't know.

[JRCART]

Mine burns oil, it has done so since the day I got it to the tune of about .5 to .6 quarts per 1000 or so miles. Nothing to worry about if you keep an eye on it. Something tells me there are going to be a lot of hypocondriac M156 owners the next few month, already two threads on MBW regarding "my car ticks" and "I smell oil". DRIVE YOUR CARS PEOPLE!

[MHP LLC]

Good advice in this thread. Jacob, try to verify the color (daytime) if possible just to be sure.

[c32AMG-DTM]

Could it have just been condensate in the exhaust? Was the smell the classic sulphuric "rotten egg" smell from the cats? Just brainstorming... might not be of much help, apologies if so.

[JonsC63AMG]

Its the multiply start ups in a short amount of time. My bro used to have a 04 GTO and had smoke like that.

[Sonny]

Its the multiply start ups in a short amount of time. My bro used to have a 04 GTO and had smoke like that.

I think you're right.

Just an update... No smoke since that that one time.

Andy, it was a thick white color smoke, if I remember correctly.

[Sonny]

Could it have just been condensate in the exhaust? Was the smell the classic sulphuric "rotten egg" smell from the cats? Just brainstorming... might not be of much help, apologies if so.

Please, no apologies, my friend.

It didn't smell sulphuric... It was more bitter (metalic/oily) than that.