Volvo 850 -- Sudden Oil Leak and Rough Running

CJFusco · Post by **CJFusco** » 28 Feb 2016, 08:53

Hey all -- I have a sudden, without-warning issue with my 1997 Volvo 850 Wagon (non-turbo, automatic transmission), and I was wondering if any of you had any ideas. I've owned the car for about 15 months, and it has 263,000 miles. Over this time, I've replaced the PCV system and had a shop replace the AC Compressor (which was making very unpleasant noises).

Yesterday, I went out to the garage, and saw a pretty sizeable puddle of oil underneath the driver's side of engine, near the back of the block. There was oil everywhere, so it was difficult to tell where the oil was coming from, but the highest point where oil is visible is a small circular protrusion off the driver's side of the engine, under the motor mount (see picture). In the photo, you can see how the lower bolt is darker (oil-covered) than the upper bolt. I'm not sure this is where the oil leak is occurring, but it looks like there's oil there.

I went out to the driveway, and sure enough, there was a small spot of oil where the car was standing while I waited for the garage door to open the night before. There were also several small dots of oil leading up the driveway along the path that I would've driven that night. But here's the weird part: there was no oil spot at the bottom of the driveway, where I would have parked for a minute or so to get the mail. There is a little bit of a bump/ledge halfway up my driveway, where the driveway goes from gravel to asphalt; part of me wonders if going over this bump knocked something loose to cause the oil leak.

I checked the oil level and it looked to be about a quart low, so I added more oil. Then I started the car to check to see if I could see it leaking. It ran fine at first, but the longer it idled, the worse it ran. It developed a "hitch" in its idle, almost as though one of the five cylinders wasn't firing correctly. At first, revving the engine slightly caused it to even out; after letting it run for a few minutes, though, it began to stumble under load. There was no check-engine light tripped on the dash. I removed the plastic spark plug cover, and it was bone-dry under there. There was the usual amount of exhaust from the tailpipe -- no more smoke than usual, and none of the blue smoke that usually denotes burning oil nor the white smoke that denotes a blown head gasket.

Here's the weird part: looking for fresh oil drips, there seems to be very little. There is a small spot on the new cardboard I put under the car, but I can't be sure this isn't excess oil dripping off the bottom part of the engine, frame, axle, etc. Letting the car run for a bit (at least until it was warm) caused a slight oil spot, but nothing I'd be concerned about if it occurred in isolation. I went ahead and moved the car into the driveway so my wife could have her garage spot back. The car stumbled a bit under load, but I was able to park it in the driveway without incident.

This morning, in the driveway, there was a small oil spot under the engine, but nothing alarming. I started the car, and it fired right up. It ran well for a minute or two, but then the idle got progressively worse. When I tried to rev the engine, it stumbled much more noticeably than yesterday, and the "check engine" light came on. At this point, I reconciled with the fact that I would need to have the car towed to a shop. Considering this, I put it in reverse so I could position it better for the tow truck, but the engine died after putting it in gear. I tried to start it again, but it started then immediately died. There was a little new oil on the cardboard under the engine, but, again, not enough to be alarming.

This seems to me a bizarre set of symptoms. Why would it leak a bunch of oil right away, but then not so much the next day? And why would an oil leak cause rough running, but only after the car warms up? Any insights that anyone could provide would be well appreciated.

Post by **cuhfs** » 28 Feb 2016, 09:29

That's the cam sensor. And probably a leaking cam seal behind it. I would remove it and see what you see.

Post by **rspi** » 28 Feb 2016, 21:32

Oil leaking there will likely cause misfires.

Post by **rspi** » 28 Feb 2016, 21:33

Best to use OEM Volvo seals.

CJFusco · Post by **CJFusco** » 05 Mar 2016, 07:25

As it turned out, somehow, one of the PCV breather hoses got pinched/crimped, which built up pressure in the crankcase, causing the cam sensor gasket to blow out, dumping oil all over my garage floor all at once. The car is good as new now. The garage floor? Well, at least it will be painted and sealed this Summer.

Thanks again for the input.

PeteB · Post by **PeteB** » 05 Mar 2016, 08:53

How did you find the pinched hose? My son's car is leaking badly but we're not sure
from where. Not as bad as yours but getting there.