oil leak from bulging o-ring at oil filter (m52tu)?

[ragged325]

I've torqued my oil filter cover down at 25 Nm as indicated on the cover, but noticed that the o-ring is bulging outwards and allowing oil to leak out. I bought a new filter to get a new o-ring and noticed the same thing happening.

Is there an easy way to avoid this from happening?

[BimmerBreaker]

Oil the o-ring before installation, make sure it sits in the right groove and double check that the previous one was removed

[ragged325]

Oil the o-ring before installation, make sure it sits in the right groove and double check that the previous one was removed

Thanks for the advice. I took the cover off to check for a 2nd o-ring and I think I figured out what I was doing wrong. I was using the ft./lbs. markings on the bottom of the torque wrench to make the incremental adjustments. I converted it to 18.5 ft./lbs. and I hope it worked out. I thought the o-ring was seated properly and wasn't bulging until I drove the car in the past, but I guess I'll find out if it starts leaking again.

[Randy Forbes]

Thanks for the advice. I took the cover off to check for a 2nd o-ring and I think I figured out what I was doing wrong. I was using the ft./lbs. markings on the bottom of the torque wrench to make the incremental adjustments. I converted it to 18.5 ft./lbs. and I hope it worked out. I thought the o-ring was seated properly and wasn't bulging until I drove the car in the past, but I guess I'll find out if it starts leaking again.

Besides never ever installing an O-ring dry, it also helps if you work it into position; in the case of the oil filter cap, turning it back and forth as it comes into contact with the filter enclosure to insure that it sinks down into its spot.

[cyberman]

Besides never ever installing an O-ring dry, it also helps if you work it into position; in the case of the oil filter cap, turning it back and forth as it comes into contact with the filter enclosure to insure that it sinks down into its spot.

Funny, I naturally do this from long-established muscle memory. Sometimes it helps to be old.

[ragged325]

I'm doing something majorly wrong. I torqued the cap down to 18 ft. lbs. and the o-ring was seated properly. I started the car and pressure inside apparently forced the o-ring to bulge out and spill oil all over my driveway.

I bought a new oil filter with a new o-ring and was not able to get it near 18 ft. lbs. before the o-ring would bulge out. I tightened it by feel/sight to just before the o-ring started to bulge and started the car. After the car started the o-ring bulged out and oil ran down the front of my engine.

I'll add that the last filter/o-ring was a Mahle and the new one was a O'Reilly one.



It seems like there may be some blockage inside the filter housing that's causing pressure to build inside and force the o-ring out??

[rf900rkw]

The o-ring is a radial seal capable of withstanding thousands of PSI. That it is bulging out means it is not installed correctly. Not even close. The o-ring goes into a groove in the cap just above the threads. The old o-ring MUST be removed first. Then you install the cap until the flange contacts the housing. This puts the o-ring 6-8mm down inside the housing, fully encased where it can not bulge.

Throw the torque wrench away. It is not needed as the cap does not need to be tight at all, it just needs to be wound on all of the way. The torque wrench is a crutch giving you a false sense of success. Dig the old i-ring out. Fit the new o-ring into the groove, and wind the cap down until the flange contacts the housing. The force required to seat the o-ring is in the upper range of what can be done by hand.

[zellamay]

I can't imagine the oil pressure forcing that o-ring out. I suggest you take it off and show us what it looks like. Do you have the old parts that didn't leak? One should always compare new parts to old parts before install. I always keep old parts for a while, in case I need to refer to them. Too many times, I've tossed them and then thought "I wonder ....."

[ragged325]

You guys are all right and I'm an idiot. I just realized where the o-ring is supposed to sit and the old black o-ring was in that groove (like BB said before). Anyway, it's fixed now.

[cyberman]

You guys are all right and I'm an idiot. I just realized where the o-ring is supposed to sit and the old black o-ring was in that groove (like BB said before). Anyway, it's fixed now.

Easy mistake to make, I almost did it myself the first time I changed the filter. And, there are two other smaller O-rings on the center shaft I forgot to install. I think they're meant to keep the reservoir full to prevent oil starvation on startup.

[DaveW3009]

10 years of oil changes on e46’s and now a z3. Never had an oil leak but… I buy Mann filters from Turner and a few from bmw, they always have a new drain seal ring and the cap O-ring, never have included the smaller O-rings on the shaft. Should I buy Mahle?

Dave W

[cyberman]

10 years of oil changes on e46’s and now a z3. Never had an oil leak but… I buy Mann filters from Turner and a few from bmw, they always have a new drain seal ring and the cap O-ring, never have included the smaller O-rings on the shaft. Should I buy Mahle?

Dave W

I'd replace every oil change since they get no pressure to self seal when engine isn't running, but that's when you need them, and they will deform a bit over time. I got my last filter at Advance Auto Parts and it included all three 0-rings.