Need Help Identifying Oil Leak

[TravisTalbot]

It looks like I'm about to purchase a 2000 Z3 (119K miles) this weekend and I need some help identifying an oil leak. I'm in the Seattle area and purchasing the car down in southern CA. Although I'm purchasing from a reputable dealership, I paid for an independent inspection of the car (CARCHEX, highly recommended). Everything on the inspection was great except one thing, a small oil leak (see pic below). I don't know enough about the Z3 specifically to identify the potential root problem of the oil leak. Can anyone make their best guess at the potential problem? I do most my own work on my cars but would like to know what I'm getting myself into. Thanks for the info ...travis

[Vinci]

That looks like the lower right-front edge of the motor. The oil is on and around the oil pan seal, so I would guess that it either needs a new oil pan gasket, or there is something above that that is leaking down. I can't see the block above that point, so I can't rule the higher leak out.

In that area, though, your likely leak points will be the oil pan gasket or the valve cover gasket leaking from above and migrating down to where you see it.

If it's a valve cover gasket leak, it's not a hard job, but it will take an hour or two to DIY. I've never done an oil pan gasket on one of these, so I can't comment on that.

[mpire]

I would expect the oil filter housing gasket, valve cover gasket, or one of the sensor o-rings before I would look into replacing the oil pan gasket.

I got a new oil pan gasket, but I haven't needed to install it yet.

[IgotBMW]

Looks to be Oil pan is leaking.

[TravisTalbot]

Thanks for your comments. In the inspection report, it mentioned it might be the oil pan gasket. Everything that has been mentioned so far doesn't sound like it would be too difficult to fix and certainly not prevent me from purchasing the car.

[mpire]

The oil pan is the last thing I would suspect.

[z3540i]

Appears to be the oil pan gasket...leaky filter housing or sensor will have wet oil running down....my oil pan started leaking this way around 90k miles just discolor then moisture and now i add 1/2 qt a day full on hemorhaging

[mnguyen84]

to clarify, when you guys say the gasket from the sensor, you're talking about #14 right?

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or maybe #19

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damn there's a lot of o-rings...

[Randy Forbes]

This is a pretty old thread you've revived, but I'm guessing that you're asking, because maybe you've recently discovered your car is wet with oil in the same spot?

The first item I would check, and experience dictates it also being the last item, is the 32mm (across the hex flats) cap that covers the timing chain tensioner. I don't know why, but these tend to loosen up, allowing oil to weep past the aluminum crush washer. Sometimes you can just tighten it up, but removing the cap (and spring-loaded tensioner behind it) cleaning the mating surfaces and replacing the seal washer is the sure-fire way to stop that source of leaking oil.

I'm with Brent, the oil pan is the last thing I'd want to remove, but here again, sometimes the bolts (particularly S-54 ones) work themselves loose. USE CAUTION upon retightening them, as the torque value is only 8 or 9 Nm (though I use 10Nm myself...).

The seal washer in this (S-54) example would be #6:

[Scarceas]

Internet forums are funny, some places it's considered poor etiquette to post a new thread, but then if you revive an old thread some people get upset. (not saying Randy was upset, just adding an observation)

I had a triple leaking going on... Oil filter housing gasket, valve cover gasket, and finally the timing chain tensioner. Only after I fixed the gaskets did I discover the leak from the tensioner. I didn't even know what it was for, but as Randy suggested I just tightened it up and I've been leak free since.

[mnguyen84]

thanks for the tip

[Vintage42]

... check... the 32mm (across the hex flats) cap that covers the timing chain tensioner. I don't know why, but these tend to loosen up, allowing oil to weep past the aluminum crush washer. Sometimes you can just tighten it up, but removing the cap (and spring-loaded tensioner behind it) cleaning the mating surfaces and replacing the seal washer is the sure-fire way to stop that source of leaking oil...
The seal washer in this (S-54) example would be #6:

The OP has a 1.9, so I guess his seal washer is #22.