smoked, but just for a second
 

happy new year to all. my 78 sc has only 69k miles on it, no oil leaks and not really a major burner of oil to this point. yesterday while out on skyline rd doing a bit of spirited driving i had a scare. i was free of traffic for about 4 miles and was at it pretty good when i came upon so slower traffic. not wanting to tag along with the sunday drive the half dozen folks in front of me were on i figured i go from where i came. on a down hill portion (approx 3 to 4% grade) i pulled off to the right, hung a quick left u turn and headed back up the hill. about 150 yards after straiting out a huge cloud of smoke came from the rear of the car and just poured in the cabin (plane reference) from the defrost inlets on the dash. after i nearly S'd myself i found a spot to pull off to examine the problem.

i found that oil was dripping down from up near the started onto the passenger side heat exchanger. during the first stop i let it sit for about 10 minutes for cooling and possiblly more of a clue as to what had failed, just a couple additional drops of oil appeared in the location, nothing major. i then started the car again and examined if more oil would be revealed while the engine had oil pressure, nothing. i then drove very mellow (with eyes glued to temp and pressure gauges) up to an area that i could get it up on a curb for more of a look-see. nothing again. i drove the 15 miles home with no further smoke, oil drips or drop in oil pressure or a rise in temp.

i looked at the oil scamatic (sp?) the bently manuel and found that the pressure relief valves were not over the area where the oil was coming from. i thought that the downhill and off camber turn may have lead to oil escaping from the relief valves. i checked again this morning and NO oil was present under the car. i understand that there is a great deal of oil plumbing in the vacinity but a oil line failure would continue to leak? any suggestions or insight that may calm me or get me pointed in the right direction? mr walker?

smoking in the hills

I suspect none of the above. What I do believe happened was when you made that quick u turn and went up hill all the oil in the oil tank sloshed to one side and oil was sucked from the oil tank into your airbox which created all the smoke. How full was your oil tank prior to the incident?

it was full, according to the dip stick before and after the drive. i thought that it had something to do with the off camber turn too. if in fact the sloshing oil into the airbox did cause it, would it vent in a location that would allow it to drip onto the heat exchanger? thank you for your help and any further input.

When you say full, do you mean the top mark on the dipstick? If so then you overfilled your oil tank which would definitely lead to oil being sucked into the airbox on a sharp turn. The proper level is halfway between the two marks on the dipstick when the car is up to operating temperature, sitting on level ground and at idle. I believe the two events you describe to be unrelated. To get the kind of smoke you described from your heat exchanger in the short period of time you stated you would need to have a very significant leak, more of the spraying oil, as opposed to a drip. After your scare I think you just happened to find a drip that had been there for awhile.

Uh Oh. I need to re-read my Owner's Manual again.

I have been filling mine to the top of the dip stick reading (just like every other car I own).

You are not worthy of owning a 930. You must forfeit it to me! :D Porsche, in a bizarre twist of logic, apparently thought if the bottom mark was to indicate the oil level was too low, then the top mark is to indicate the oil level is too high.

kurt, if the oil did enter the airbox would it just enter the combustion chambers? because again a great deal of smoke entered the car from the defrost vents, meaning it would have needed to burn prior to the heat exchanger inlet. thanks again!

Did the same thing.....killed all the flies and mosquitos for ten blocks around.....NOW....I always keep the oil at the lower level on the dipstick. First time ya do it, it embarasses the hell out of ya.

With the amount of smoke you described I am sure it got sucked in thru the fan housing and into the vents!

it can drool out of the airbox and down onto the right exchanger. there should be a little brass tube full of copper wool in the tube on the filler neck behind the oil cap, or in that end of the hose that attaches to it. it helps to keep liquid oil from sloshing up the hose. you can also raise the hose so oil can't pass as easily.

thanx both mr. walker and kurt, i was really scared there for a time. im better now.