fiftyfive

My '87 930 is stock 70kmiles. I've driven it 16kmiles in the last three years of ownership with little oil consumption and only an occasional puff of smoke on start-up. In the last few weeks the puff has turned into a cloud, and when the car is shut off, 10 or so drops of oil drip out of the wastegate exhaust outlet as it cools.

I searched and read prior threads on this subject but didn't see anything about wastegate dripping. Here's what I know:

1) In hindsight I discovered that the oil was overfilled a quart at the last change in November. Nov-Mar I drove it 1000 miles in cool weather. No problems.

2) As outside temperatures increased, start-up puffing occurred whenever the car sat a few days.

3) Last Friday I drove the car 50 miles in eighty degree heat, including being stuck in traffic a bit. Oil temp went to about 220. The next day is the first time I saw the wastegate pipe drip.

4) I drained about a quart of oil out of the tank on Sunday, getting the level toward the low end of the dipstick. Tonight I noticed it still dripped; the car blew a lot of smoke and stumbled briefly on startup. Might be a lot of accumulated oil in there still?

5) No smoking after restart or when revving hard, car runs great.

From prior threads, three causes could be a) aftermath of oil overfill, b) problem with scavenge circuit or a vacuum condition, c) turbo going bad. Any thoughts appreciated. My shop will need to look at things, but I've found it's better to go in with some information.

Thanks,
John

911rudy

I did the same thing by over filling and had oil leaks for several months afterward. You difinitely have oil in the IC so it's natural for oil to get into the WG. You could disconnect the tube from the WG to the IC and run some carb cleaner in it but the real culprit is the IC. It will have a lot of oil in it for a long time and will have to work it's self out. I had leaks in some of the hoses from the air intake to the crankcase too. I finally took a hose and siphoned some oil out of the tank to control this mess. It will eventually clear up.:-)

Mark Houghton

+1.
Pull the IC off and fill it with a good soapy detergent and water. Slosh it around, let it sit awhile, drain and flush. Get that oil out of there, if for any reason other than to maximize heat transfer and air cooling. I did this to mine recently 'cause my turbo compressor blows just a little oil mist.

fiftyfive

Gentlemen,

Many thanks, sounds like the weekend project's been set. To keep the first post from being even longer, I didn't mention that the IC was off several weeks ago when the weather was cooler, so I could change the coil and CDI box (unrelated). There was slight oil pooling in the duct flanges and a film on the throttle plate. After last week's hot run, bet it could be worse now.

fiftyfive

This weekend I pulled the intercooler and sat it upright overnight with the inlet at the bottom. An ounce or so of oil pooled there overnight. The next day I set the IC upside down and filled it with a quart or so of mineral spirits, agitating gently and turning upright a few times with my hand over the inlet and wastegate nipple. Afterwards it looked clean as a whistle.

I wiped down the throttle area and anything else accessible and reassembled. Start-up smoking is dramatically less and there's no more wastegate exhaust drip. Getting the extra quart of oil sucked out was probably the first necessary step, cleanout the second.

Really appreciate your guidance.

A930Rocket

Now check your oil to make sure it's halfway on the dipstick marks....

fiftyfive

It's a quarter of the way up from the low mark. I'll add a quart when it hits or goes below the mark. I should've pulled a quart out just after the oil change in December when the level hit the high mark at 190-195 deg. First day at 210-220 was a wake-up.