Exhaust smoke on 79 450 SEL

[Johnex]

What does exhaust smoke indicate on an older Mercedes? It is not heavy smoke and it is not very light either....it seems to go away when driving. I see more of it when Idling.

The smoke is light in color, not dark.

Thanks,

John

[Johnex]

ps: the smoke is white with maybe a hint of blue

[Tomguy]

Valve stem seals. On an engine that old they are almost surely shot. Mine were on my 4.5 - it's not that hard of a job, just time consuming to do all the valves. How many miles on the engine?

[Johnex]

My guess is 130,000 based on when the owner bought the car and his driving habits since the odometer broke.

[michaeld]

White smoke could also indicate a blown head gasket. That would be bad.

Make sure you don't have any oil in your expansion tank (coolant). Make sure you don't have any white or yellow gunk on your oil cap. Make sure you aren't overheating.

In the case of a blown head gasket, the white "smoke" is actually water vapor from your coolant entering into the engine exhaust. The fact that it's got a hint of blue means Tomguy's probably got it right. Still, it's best to check the obvious and easy to ID things first.