Northstar Engines and System Technical Discussion Discussion, Smoke after shutdown... Classic N* oil leak issue? in Cadillac Engine Technical Discussion; I have been noticing since we bought this 98 STS that off and on after the car is shut off, ...
Automobile(s): 1992 STS / 2005 MB G500 / 2008 Mini Cooper Clubman S
TPA / STL / ICT / SAT
Smoke after shutdown... Classic N* oil leak issue?
I have been noticing since we bought this 98 STS that off and on after the car is shut off, especially at night you can see a pretty good quantity of what appears to be white smoke wisping past the headlights for at least several minutes after the car is shut off. The worst it ever got was once when I was idling at a stop light and I could actually see it starting to billow out of the wheel houses and front of the car. Exhaust works fine and doesn't appear to leak.
The car *does* have a weak power steering pump and a small PS leak from the area of the pump, however I don't believe the fluid leaks on anything hot enough to justify that much smoke.
Also, the smoke definitely has a burnt oil odor which leads me to believe it is most likely oil being burnt on the underside or exhaust headers, as well as the fact that a couple of times I've caught it coming out of the top of the rear of the motor (firewall side) and also once when I was shining a flashlight on the passenger side where the serpentine belt is I could literally see it lightly "puffing" out of what looked like the middle of the engine casing...
So my question is this...
Assuming this is more of an UPSCALE "beater" than anything for me right now (I'll be driving it the most) and being that I don't really expect this tired old girl to last much more than a couple of more years if we keep it, what can be the downsides of throwing oil additives in (like an oil thickener) or just going with a heavier weight oil altogether to try to alleviate or detect whether this even IS the classic Northstar case half leak? Coolant loss and headbolt issues are NOT negotiable for me and if the car ends up having THAT issue it's getting dumped, but the case half leak I'm alot more flexible about since you can seemingly just top it off for eternity, and thus my question.
As of yet my answer to the question of whether I see oil on the floor is inconclusive, Ive been trying to remember to look at the ground after I park somewhere for a while but I always forget, however Im pretty sure I have seen a couple of drops that came from this car and were either oil or PS fluid. Oil consumption is also somewhat inconclusive at this point but assuming the prior owner changed the oil just before we bought it (it had 120k and there's a sticker in the window for next change at 123k) and what I observed on the dipstick after 1000 miles, it has used about a quart thus far.
So yea, basically looking to see what the best band-aid fixes are for a N* with that ubiquitous leak. Love this car, but not enough to sink 1800.00 into a case-half repair if it can be nursed along indefinitely. I just don't know what the "worst case scenario" involves with the oil leak issue, or how bad the worst ones can get.
Automobile(s): White Diamond '03 DHS (with DTS floor shift)
Re: Smoke after shutdown... Classic N* oil leak issue?
Try 10W40 and see if that slows it down. The halfcase (if that is what it is) usually is nothing more than a nuisance leak that you can live with for a long time. Also be sure it is nothing simple like the oil filter adapter, pressure switch or oil cooler line fitting.