oil leaking at oil filter

[benzboy]

hey this is a dumb question. i have oil leaking around the filter. the oil filter is tight. is there a seal or o ring on the oil tank where the oil filter flange mounts? i hope so. i really dont want to fix of buy a new oil tank. thanks

[tuchan]

There is a seal on the filter.

See if the filter is tight and snug. Not too tight to deform the seal. You just want it on there so it wont leak and wont come loose.

Unscrew the filter, make sure the seal is good and re-install. May as well put a new filter (and seal) on whilst doing so.

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[emac]

Always wipe the rubber seal on the filter with some oil. Hand tight no oil wrench

[rwest]

Might also check and make sure the seal from the last filter isn't there too; pretty rare, but sometimes the old one comes off the filter and sticks to the mount, double seal will cause a leak.

[mcaterino]

Year? Early tanks (which I know) and maybe later ones (which I don't) have the oil filter base screwed to the tank, sealed by an o-ring. Corrosion around the base or simply an old crunchy o-ring can cause a leak. I had quite a problem with this myself, which unfortunately in my case was due to gashes in the tank, requiring complete replacement.

Mike

[chococrazy]

Originally Posted by rwest

Might also check and make sure the seal from the last filter isn't there too; pretty rare, but sometimes the old one comes off the filter and sticks to the mount, double seal will cause a leak.

Yup watch out for a double gasket- being a grease monkey I've seen them cause problems first hand. Some shops even double gasket valve covers

[KTL]

Sometimes people don't tighten the filter enough because the rubber "pad" on the oil tank interferes with the filter can. What I mean is, the pad rubs on the filter and makes it difficult to spin. I always put a swab of grease on the pad to reduce the drag on the filter when tightening it

[motorcop]

+1 on the double gasket.....ask me how I know

[Sunroof]

Hey Benz Boy,

We have to know what year the car is for a better assessment. I had the same problem and even changed out my filter a few times until I realized that the leak came from the tank itself. So fellow me on this one:

The tank is held to the body by two fittings. You can see them bolted on in the engine compartment with large washers. These fittings which are really long bolts are welded onto the tank by a small sort of "A" frame. This piece is welded to the tank. A weak link in the system. Over time, vibration and heat will create a crack in the weld that holds the "A" piece to the tank. Its almost too small to see like a hairline crack. As the oil rises from heat during operation the oil will leak through this crack and weep down on the filter creating the illusion your filter is messed up.

Its hard to see it in the engine compartment. The challenge is getting to the tank because its snugged up in the fender well and tough to remove unless you remove the lower fender/bumper which is pretty easy.

I took my tank off, had it boiled at a radiator shop (no need to paint or coat the inside), had a welder weld a large bead where the leak occurred and the other side for good measure and coated the tank with good old POR 15. Almost brand new.

Another early 911 lesson................

Good luck


Bob
73.5T

[Joe Bob]

Worst oil leak I ever had was a double gasket on an Austin Healy......I had to pull the assembly out to see it and pull it out.

[juanbenae]

Originally Posted by rwest

might also check and make sure the seal from the last filter isn't there too; pretty rare, but sometimes the old one comes off the filter and sticks to the mount, double seal will cause a leak.

+1

[bourgeois911]

Originally Posted by Joe Bob

Worst oil leak I ever had was a double gasket on an Austin Healy......I had to pull the assembly out to see it and pull it out.

I've done this TWICE, but not on the 911 yet. You'd think that I'd learn.

[benzboy]

sorry the car is a 11973 911 e. its not leaking at the filter. i dont think i explained it right. i feels like it leaking at the part the filter screws into,. that part which is mounted to the oil tank. i would call it the flange, but probably wrong about. like i said, the filter isnt the problem.

[mcaterino]

As I said, the filter base or console (your 'flange'), #8 in this pic, has an o-ring (#9) that can leak. IF the base is corroded, which is common, or the o-ring is aged and cracking, also common, you can get leakage from the filter base.

[benzboy]

ok i see. i dont have the car right now. its in the shop. looks like its just 1 bolt to take the flange out.