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Blue smoke at startup

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Old Jun 18, 2020 | 08:47 AM
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rick hesek's Avatar
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2014 CLS550
Blue smoke at startup

Hello all,
I searched all forums with ref to the M273 engine and couldn't find any info regarding my issue.
I'm getting a puff of blue smoke at startup but only under certain conditions. This does not happen every startup.
  • After sitting over night, at startup, it is nice and clean. Not even an odor. I put a few miles on (20-30) at full operating temp. and shut it off.
  • Let it sit for a hour, then start it, clean, no smoke, let it idle for a minute, then shut it down.
  • 10 minutes later, startup and a puff of blue smoke.
Also, if I slow down from highway speed to a stop, like at the end of an off ramp, then accelerate, no smoke.
I have 141K miles on and I changed the oil separator, (centrifuge) cover and hose 5k miles ago since it was weeping oil externally.
The car still has tremendous power and runs smooth as silk.
Perhaps valve stem seals, but wouldn't it smoke more often?
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