A mysterious oil leak

[LucasElectrics]

Can anybody help me with a mystery leak?

I have an '01 330xi. For the first year it never leaked any engine oil. The light never went on. After the dealer did the first major servicing it started to leak very slowly. The low pressure light would sometimes come on after I turned off the engine. So every once in a while I would top it up.

Recently it has got a lot worse. Three weeks ago, after the light came on while I was driving, I filled it with a liter of oil. A few days ago it went on after I turned off the engine and then yesterday it went on while I was in heavy traffic. I went to the nearest place to buy oil, checked the level (it was at minimum) and put in a liter. Then when I went to my dealer this morning they put it on a hoist and showed me that there was no leak -- no oil visible anywhere. So where is it going? It isn't going on my carport floor, either.

The dealer says that they siphon out the oil when they do an oil change, so the drain valve never gets opened.

What do you think is happening?

[Lanc3r]

Can anybody help me with a mystery leak?

I have an '01 330xi. For the first year it never leaked any engine oil. The light never went on. After the dealer did the first major servicing it started to leak very slowly. The low pressure light would sometimes come on after I turned off the engine. So every once in a while I would top it up.

Recently it has got a lot worse. Three weeks ago, after the light came on while I was driving, I filled it with a liter of oil. A few days ago it went on after I turned off the engine and then yesterday it went on while I was in heavy traffic. I went to the nearest place to buy oil, checked the level (it was at minimum) and put in a liter. Then when I went to my dealer this morning they put it on a hoist and showed me that there was no leak -- no oil visible anywhere. So where is it going? It isn't going on my carport floor, either.

The dealer says that they siphon out the oil when they do an oil change, so the drain valve never gets opened.

What do you think is happening?


If its not leaking anywhere, than it is burning. I had a similar incident, after my first oil change (2000 323ci) My Oil warning light came on. But, my whole engine bay was covered w/oil. Later found the dealer didnt replace the seal at the oil filter. I suppose you could only be leaking oil, when you have oil pressure, as I was. But you would find where it was spraying very easily. I would reccomend running the car in the driveway and look for leaks, or blue smoke out the exhaust. Good luck! :thumbup:

[LucasElectrics]

Yeah, I think you might be right about the burning. Back to the dealer I go!

Thanks for the reply.

[streetk14]

Just wondering, is the yellow oil light or the red oil light coming on? The yellow light is for oil level, the red is for pressure. The low oil warning should only come on when the level is at least a quart low. Keep a record of your oil consumption & make sure to check your oil level on level ground for consistancy. According to BMW, a fair amount of oil consumption is normal. It is possible that you have a bad sensor, and there is also an SIB on recoding the LSZ module for the low oil light illuminating (with a full oil level). Hopefully, you don't have a oil consumption problem. Still have a warranty? ;)

[LucasElectrics]

Fortunately, I've never seen a red light -- and I hope I never do! :yikes: When the yellow light comes on, it is usually after I turn off the engine. When I check the level, it looks ok (maybe 90% between min and max). I have heard that the sensor can be a little oversensitive, so I started ignoring it. I wasn't really worried until about three weeks ago, when it came on while driving, and when I checked it, it was near min. I filled it, and now it has happened again.