freeflyr
12-21-2010, 04:25 PM
Alright, here's one to make you think:
Got in the car ('98 328is) this morning, started it and let it run for a minute or so (outside temp ~0 degrees F) before leaving. Drove about 2 miles, came to a stop sign. All was normal until this point. Pulling away from the stop sign, the car began making very little power, check engine light on, lots of white smoke. Immediately pulled over and the engine stopped. First thought was head gasket, so I went and smelled the exhaust. No coolant smell, but rather very hot burned oil kind of odour. Popped the hood, found no major oil or coolant leaks, tried running the car again. Extremely low idle speed, very rough running, etc... I pulled the dipstick to check for coolant in the oil, and when I pulled it, oil began to shoot out of the dipstick tube. Not boiling, as some got on my hand, and was not that hot. The sound it made seem more like air was pushing oil out. At this point I'm pretty convinced I've blown a piston ring. I call for a tow and while I'm waiting, I decide for some odd reason to try running it and pulling the dipstick again. This is where it gets weird...
The car idles perfectly. No vibration, normal idle speed, check engine light has gone off, and no oil out the dipstick. As I'm so close to home, I decide to limp it back and regroup. I obviously babied the car for the whole drive, but it seemed to run just as normal and make normal power. It burned white/blue for most of the drive, but it decreased the more I drove, until the exhaust was perfectly normal by the time I was 1/4 mile from home.
Any ideas? The oil being pushed out of the dipstick tube would lead me to believe there was (at least for a while) increased crankcase pressure. Maybe a frozen up PCV valve that had time to thaw with the engine heat while waiting for the tow? Only question if that is the case is what is oil doing getting in to the cylinders to be burned? I can't see the crankcase pressure being high enough to push oil backwards across the piston rings and into the cylinders...
Edited to add: Just did some more reading and found this may be a common enough problem and oil was flooding into the intake... Any thoughts?
Got in the car ('98 328is) this morning, started it and let it run for a minute or so (outside temp ~0 degrees F) before leaving. Drove about 2 miles, came to a stop sign. All was normal until this point. Pulling away from the stop sign, the car began making very little power, check engine light on, lots of white smoke. Immediately pulled over and the engine stopped. First thought was head gasket, so I went and smelled the exhaust. No coolant smell, but rather very hot burned oil kind of odour. Popped the hood, found no major oil or coolant leaks, tried running the car again. Extremely low idle speed, very rough running, etc... I pulled the dipstick to check for coolant in the oil, and when I pulled it, oil began to shoot out of the dipstick tube. Not boiling, as some got on my hand, and was not that hot. The sound it made seem more like air was pushing oil out. At this point I'm pretty convinced I've blown a piston ring. I call for a tow and while I'm waiting, I decide for some odd reason to try running it and pulling the dipstick again. This is where it gets weird...
The car idles perfectly. No vibration, normal idle speed, check engine light has gone off, and no oil out the dipstick. As I'm so close to home, I decide to limp it back and regroup. I obviously babied the car for the whole drive, but it seemed to run just as normal and make normal power. It burned white/blue for most of the drive, but it decreased the more I drove, until the exhaust was perfectly normal by the time I was 1/4 mile from home.
Any ideas? The oil being pushed out of the dipstick tube would lead me to believe there was (at least for a while) increased crankcase pressure. Maybe a frozen up PCV valve that had time to thaw with the engine heat while waiting for the tow? Only question if that is the case is what is oil doing getting in to the cylinders to be burned? I can't see the crankcase pressure being high enough to push oil backwards across the piston rings and into the cylinders...
Edited to add: Just did some more reading and found this may be a common enough problem and oil was flooding into the intake... Any thoughts?