Hi guys,

I'm helping a buddy with a 1979 240D. When it has been sitting for any length of time, it has a really smoky start. It will continue to smoke until it it warmed up, at which point the smoke is very minimal. I am assuming this is likely valve stem seals, and I'm going to try and help him swap them out (it's affordable and apparently not too hard). Does this sound like a reasonable diagnosis/cure?

It does have some blow-by, and he purchased a compression tester, so we're going to pull the glows and try and check the compression, probably after we change the valve stem seals, and adjust the valves.

I helped him with a MMO piston soak and a diesel fuel system purge (using Sea Foam) and pretty much eliminated the BLACK smoke (which said to me his injectors were fouled), so the smoky starts are all from oil - the smoke is bluish white, and it certainly smells like burning oil, not diesel.

I've told him that it's possible that the blow-by is either from sticky rings, or from carbon/varnish build-up on the cylinder walls (it has under 200K miles) or perhaps the PO didn't change the oil enough, and it's just plain worn. I told him to "just drive it" if we can fix the smoky start.

(EDIT: I now suspect that the car has been run on WVO, as there is evidence of a heat exchanger installed in the engine bay - see the photo in post #12. It is certainly not stock, and I can't think of any reason why one would want to heat up the diesel fuel around here in the Pacific NW. It's likely some hippy fed it a diet of WVO or SVO. If so, then I am also considering how we could remedy the damage that has been done - possibly from stuck rings? Or carboned-up cylinder walls? I even suspect that the car has more miles than are indicated by the Odo, as the manual transmission certainly has more 'I'm worn' noise to it than my 83.)

Don't know what his oil consumption is.

His vehicle has less power than my 83, but I also know that the 83s have a few extra horses. His is a 79 MY.

Any hints, tips, or advice is welcomed!

Thanks,

PE

__________________
83 240D - 4 speed manual - Manilla Beige
189K miles, Tachometer mod, cool wooden shift knob from PeachParts, CocoMats, Original factory paint, manual windows, manual sunroof. Starting to add AudioWrap to this car too!