Sorry to resurrect this, but I just finished a major 'mechanic in a bottle' treatment this morning on my '85 380SE. The smoking out the pipe I originally posted had gotten REALLY annoying, to the point that cars following me were dropping back to avoid a cloud when I accelerated from a stop-light! It was pumping out a steady blueish flow at idle too, worse when I stepped on the gas, and when the engine warmed up.
OK, so what I did was:
- Drained out about a liter of oil, so the dipstick reading was about 1/8" below full-max marker.
- Put in a 354ml bottle of Pennzoil 'Engine Flush', ran as instructed for 10 - 15 minutes, then drained out all the old oil (except the filter, which I left in in case I needed to repeat the exercise).
- Re-filled with fresh 10W-30 Quaker State, ENSURING the level was bang on the max-full mark.
- Poured 1/3 can of Seafoam treatment (as specified for 8 cylinders) slowly into the throttle plate opening, shut the engine down for 10 - 15 minutes, then started it up, with huge billowing clouds of smoke coming out the tailpipe, as the Seafoam can said it would.
- went for a nice long drive and returned home to what has, so far, been an almost completely smoke-free tail-pipe! Hooray!
I don't really know if I'd have gotten the same results if I'd simply drained the oil and re-filled to the right level. Probably would have, as it would seem that the excess oil I stupidly put in in the first place simply raised the oil pressure enough to force it past the oil rings and into the combustion chamber. This is also consistent with the increase in blue smoke after the engine had warmed up, and with the noticeable lack of appreciable smoke on start-up after sitting overnight (which was why I put in the new valve seals 2 years ago).
This sure isn't an endorsement for Bardahl Smoke Stop, but it isn't a condemnation either. The lesson is maybe that over-filling the oil creates SERIOUS smoke, which is very unnerving, but in the end is probably no real biggie either.....