OK so this only happens when I've been stretching the legs of the coupe for more than 10 miles (that means 90+ MPH).

Anyway, say I'd be doing the latter...all of a sudden I'd see smoke coming from me in my rear view.

I pull over and there's dark grayish smoke coming from the back of the engine. Smells like a combination of coolant and rubber burning...maybe oil. The mix is too weird to confirm its oil but thats a rough idea.

I was thinking o ****, head gasket but there's nothing in the coolant reservoir to say other wise. THere's no abnormal exhaust smoke, meaning nothing abnormal at all about it. Smell included

Nothing comes into the cabin either, it's seeing it come out the back in the rear view.

Oil pressure remains normal, temperature remains normal (especially since I had it redone this past summer, it should).

I remember I was on the turnpike and I would see it...and it was almost as if I was burning oil from bad piston rings or something. Everytime I would let go of the gas then get back on it, is when i saw it the most. That same day after pulling on the shoulder to see where it was coming from, i drove normally back for the remainder 30 miles of my trip and everything went back to normal (smoke wise). When this happened, again, oil pressure, normal. Temp, normal. Oil level, normal. Coolant, normal. Trans fluid, whaddya know. normal.

I did the same fast driving on my way up to Canada and the same exact thing happened.

And again, this is only if I've been driving for 10+ miles at 90+ MPH and it's happened nearly every time I've done so, this means wide open throttle, and a fair amount of kick downs. Car is regularly serviced by MB specialist and we have not found anything abnormal.

What could this be?

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1975 W116 280S - SOLD
1994 W124 E320 Coupe - Gone

CURRENT - 1974 450SEL - 1987 560SEL