M50 Oil Pan Gasket Experience :(

[scotbotmosh]

M50 Oil Pan Gasket Experience

This weekend I replaced the oil pan gasket on my '95 525iT. I did my homework, read through every post I could on here and other BMW forums. Everywhere I read (even in my Bently manual) seemed to state that I didn't have to drop any of the cross members to perform this. Although it I could not get the oil pan out unless I dropped the crossmember that runs under the bellhousing/ oilpan. It seemed to be caught on the aluminum plate that runs under the lower bearings. So I did not drop the pan. I was able to clean off the engine block and oil pan and slide the new gasket in. I thought I did a good job cleaning both surfaces and used a tiny bit of RTV gasket sealer in the front of the pan. I started the car up and ran it for about 10 minutes and it was leak free. I then took it on a 20 minute drive 10 min on the highway/ and 10 minutes of city driving, when I got out I looked under the car and it was a rainstorm of oil. I am puzzled as to why this happened. I tightened all the bolts to 10NM just as the book suggested. Looking back I may have been able to clean the pan better if I could have actually gotten it out, other than that I double checked all the bolts on the pan and made sure to hit them all with the torque wrench to make sure the tension wasn't too little/ or too much. Any ideas?

[healtoeit]

Any ideas?

Tighten the bolts around the leaking area. Although their is a torque spec, you will NOT damage anything by tightening them more (you just put more pressure on the gasket). Just don't strip the threads. This will most likely solve the problem.

[scotbotmosh]

I will try giving them all another 5Nm and see if that reduces the leak.



Because it didn't leak when I first started it up and ran it for 10 minutes, and then after 20 minutes of real driving it did leak, do you think it could be heat related? Say, the engine warmed up and the aluminum pan expanded allowing a smal gap and then letting the oil leak out, therefore maybe just tightening the bolts will rectify this?

Thanks,

[BMWCCA1]

Did you drop the oil-pump pickup and rotate the crank to clear the rear crank throws?

[scotbotmosh]

I did drop the oil pump pickup, I did not rotate the crank though
because it was not hitting the crank, it was hitting the
metal shield under the crank throws so it wouldn't have done any good

[healtoeit]

do you think it could be heat related? Say, the engine warmed up and the aluminum pan expanded allowing a smal gap and then letting the oil leak out, therefore maybe just tightening the bolts will rectify this?

I think that the heat would the oil temp to rise and in return the oil becomes less dense and therefore easier to get out of little cracks like the one in your oil pan. Personally if it was me I wouldn't use a torque wrench. I would just tighten them until the nut stops, then tweak them a little bit. Again just be careful not to strip anything! It may sound but once you do it a few times and no oil comes leaking out it becomes commonplace.

[Ken35i]

What was the gasket material?

[scotbotmosh]

I think that the heat would the oil temp to rise and in return the oil becomes less dense and therefore easier to get out of little cracks like the one in your oil pan. Personally if it was me I wouldn't use a torque wrench. I would just tighten them until the nut stops, then tweak them a little bit. Again just be careful not to strip anything! It may sound but once you do it a few times and no oil comes leaking out it becomes commonplace.

Actually because it is 10-40 oil the oil will get thicker at higher temps. but I will take your advice tomorrow night and snug them up a bit more and hope for the best. Thanks!

[scotbotmosh]

What was the gasket material?

It was the stock gasket from the dealer. Metal on the outside, rubber on the inside ring.