Oil Tank Leak

[bhaubold]

The oil tank on my 67S has been leaking somewhere from the top of the tank. Or at least somewhere I can't see.

Is there a common spot these tanks can leak from? I'm looking for a hint before I remove it.

Thanks,

Bob

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Bob,
59 A coupe
67 911S

[john walker's workshop]

the bracket at the upper pointed end of the tank fatigues the metal it's spot welded to. removal required. usually you can sweat some brazing rod around the bracket. flush the tank before and after welding. oil will flame on, given enough heat.

[bhaubold]

Originally posted by john walker's workshop:
the bracket at the upper pointed end of the tank fatigues the metal it's spot welded to. removal required. usually you can sweat some brazing rod around the bracket. flush the tank before and after welding. oil will flame on, given enough heat.

Is that something a radiator shop might be able to repair after I remove it?

[john walker's workshop]

i would imagine. they fix gas tanks too.

[joesplace62]

You may want to check the o-ring between the oil filter mount and the tank itself. On my car the o-ring had turned to rock and was leaking a lot. Good luck

[sessa]

My 70 S was leaking from around the hose at the filler neck as well. Fixed it with some 2 inch hose for a $2.00 and it has been fine since. When it was leaking it leaked a fair amount I am assuming as the oil came down the breather hose and found its way onto my garage floor

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1970 911S

[Jim Sims]

First place I'd check is the o-ring that attaches the oil filter console (mount) to the tank. If you're lucky this will be the origin of the leak as the 0-ring is easy and cheap to replace. The other place to look is on the very top of the tank along the seam. Unfortunately debris collects here and retains moisture; this can and does rust the tank form the outside in. If there is a perforation it probably can be repaired by welding or brazing but looking for a good used tank and cleaning it up well might be a better option. Lower leaks can be from the oil level sender flange gasket; it is cork and becomes hard with age. Jim

[Hatari]

Also, there is a cork gasket between the tank and the sending unit. My 72' was leaking there and it is an inexpensive part, but the tank had to come out to install it. Had the tank boiled out while it was out. No more leaking though...
Jack McAllister

[Jim Sims]

The oil level sender flange cork gasket can be replaced with the oil tank in the car (but drained of oil). The level sender has to be flipped and rotated to get it into the right position to pass the float through the opening. The cork gasket typically comes off in pieces though and care should be taken not to let the pieces fall into the tank. As I removed the gasket I reassembled it to ensure I had it all off and that I didn't lose a piece into the tank. Cheers. Jim

[Jim Sims]

Bob, If you elect to remove your oil tank there should be plastic washers in the grips of the studs which bolt to the body and there is also a square plastic piece in the grip of the bolt which attaches the tank bracket to the bumper end support (a tube like piece). Given their age, they are likely hard and distorted. Get replacements for these pieces (they are still available) as they isolate the oil tank from body flex and allow differential thermal expansion (cold car body vs. hot oil tank) to be accomodated. Failure to reinstall these pieces will mean the tank will be hard bolted and the fatigue cracks John Walker references will manifest themselves in your tank. Also, the rubber collar around the oil filter console (mount) may look like hell when you get the tank off. I have seen them with one side hard and the other side a sticky mess like the the rubber wasn't vulcanized. You may want to replace this piece too if it doesn't clean up. Cheers, Jim

[Roland Kunz]

Hello

Oil tanks do rust too.

Grüsse