Blue smoke puff on my C300 !!!
10-18-2010, 07:32 PM
#1
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2009 C300 4matic luxury
Blue smoke puff on my C300 !!!
Hi all...After my C300 sat for about a week, I noticed a puff of blue exhaust for a moment at initial cold startup....needless to say I was unpleasantly surprised...I have not been able to duplicate this in the last few days...I've had this car for 3 months, and admit I have driven it a bit slow,mostly stop/go,....It has 15,000 mi on it, and oil was supposedly changed when I bought it as a CPO...I assume dealer used Mobil1 ???....Oil level seems full...Any comments..suggestions ?...Should I be " blowing it out " every few days ?...Thanks 
10-19-2010, 05:33 AM
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2008 C300 Sport 6MT X-Pipe
This has happend to me too! My finding: If you start the car to move it, make sure you let it run at least until the idol kicks down or you will have blue/white smoke on the next startup. Unburned fuel must end up somewhere without proper warmup. 
10-19-2010, 06:21 PM
#4
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I suggest the blue smoke is more likely oil rather than fuel.
Oil must be entering the combustion chamber over the week lay off.
It could be oil vapour that has condensed in the valve cover draw off pipe & being burnt at start up.
Oil leaking past oil valve stem seals can cause this also.
I suggest that you have it checked out whilst under warranty.
Keep a close eye on your oil level.
Oil must be entering the combustion chamber over the week lay off.
It could be oil vapour that has condensed in the valve cover draw off pipe & being burnt at start up.
Oil leaking past oil valve stem seals can cause this also.
I suggest that you have it checked out whilst under warranty.
Keep a close eye on your oil level.
11-17-2010, 07:46 PM
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2009 C300 4matic luxury
Occasional blue smoke at cold start
After studying this situation on my C300 I have determined that our cars do NOT like to be coldstarted then shutdown more than once or twice without at least some warmup....I think JFOUR hit the nail on the head....I have not been able to repeat my experience, until I forced the situation by starting the car cold backing it out of garage,shutting it down, starting it to move it , shutting it down...then letting it sit for a day...The following morning I started it, ran to rear of car and noticed a bit of light blue then dark puff on exhaust, then she ran clean !!....A bit strange...but then again this is my first Benz...ps- My oil level is , and has been at the full mark....PS...I do love this car,and am impressed in so many ways....
11-17-2010, 08:56 PM
#6
MBWorld Fanatic!
After studying this situation on my C300 I have determined that our cars do NOT like to be coldstarted then shutdown more than once or twice without at least some warmup....I think JFOUR hit the nail on the head....I have not been able to repeat my experience, until I forced the situation by starting the car cold backing it out of garage,shutting it down, starting it to move it , shutting it down...then letting it sit for a day...The following morning I started it, ran to rear of car and noticed a bit of light blue then dark puff on exhaust, then she ran clean !!....A bit strange...but then again this is my first Benz...ps- My oil level is , and has been at the full mark....PS...I do love this car,and am impressed in so many ways....
11-18-2010, 02:07 AM
#7
MBWorld Fanatic!
After studying this situation on my C300 I have determined that our cars do NOT like to be coldstarted then shutdown more than once or twice without at least some warmup....I think JFOUR hit the nail on the head....I have not been able to repeat my experience, until I forced the situation by starting the car cold backing it out of garage,shutting it down, starting it to move it , shutting it down...then letting it sit for a day...The following morning I started it, ran to rear of car and noticed a bit of light blue then dark puff on exhaust, then she ran clean !!....A bit strange...but then again this is my first Benz...ps- My oil level is , and has been at the full mark....PS...I do love this car,and am impressed in so many ways....
