1970 911e oil tank

[peko]

My oil tank is leaking and my mechanic said the seals are bad. He wants 400 to do it? I was thinking of doing it myself….Any thoughts? What seals do I need to order before I start? Thanks Casey

[304065]

That doesn't make a lot of sense to me, one doesn't typically hear about oil tank seals going bad. Sure, there is a seal at the drain plug, and there are seals under the filter console and between the body and the tank itself, and the rubber hose at the filler neck, but 1) those things do not cost $400 to fix and 2) they don't usually leak.

Here is a photo of what I mean:



52 is a crush washer
9 is a rubber o-ring underneath the filter console
28 is a seal between the level sender and the body of the tank
46 is a rubber bellows around the console (vibration isolation)
48 is a rubber donut around the base of the filler neck (vibration isolation)
33 is the rubber pipe that connects the filler neck to the neck on the tank; and
32 is the seal under the cap.

That is about it. To do this yourself you have to drain the oil, CAREFULLY remove the S hose and the scavenge hose from the tank (oil line wrench and PATIENCE required), remove the filter console (three m6 cheese-head screws), remove the filler neck (standard screwdriver to remove lower clamp) then remove the two M8 lock nuts on the studs through the firewall that hold the tank in place. It's easy to lose, or to mix up, the clear plastic washers that isolate the studs from the firewall-- make CAREFUL note of the order that things come apart so you can 1) order replacement parts without having to buy everything on the list and 2) get it back together again. Then you remove the lower support that bolts to the J-tube (do LWB cars have a J-tube, I can't remember, I don't think so) and carefully winkle the tank out without scratching it. You will get dirt, oil, grease and crud everywhere. Just don't get any INSIDE the tank.

Now you have a greasy, cruddy tank with 40 years of dirt accumulated on the top side of the tank inside the fender. If it's ever going to leak, this is where the leak's going to come from, on top. That's where the dirt accumulates. So you should probably send the tank to Pacific Oil Cooler for ultrasonic cleaning and repainting before it goes back in the car. I did this a few years ago with a FABCAR tank and it comes back looking like this:



Ignore the extended capacity, you get the idea. It's not particularly cheap sending it out and back and for the service, but after 40 years it's probably worth it. And you will learn of the existence of any pinholes in the tank which are the REAL reason the tank leaks. www.oilcoolers.com is the link for Pacific Oil Cooler.

"Installation" as they say in the old British Car workshop manuals, "is the reverse of removal."

You can find the parts on most online sites using their diagram to locate the modern (superceded) part numbers for the bits you need.

Good luck!

[peko]

Thank you for the advise and info it is very helpful and it is greatly appreciated. Thanks again. Casey

[csbush]

I don't disagree with pulling the tank and doing a complete refurb, but if it is only seals, you really only need to replace these two parts:

9 is a rubber o-ring underneath the filter console
28 is a seal between the level sender and the body of the tank

You don't need to pull the tank to get at them.

[37yrold911]

It's also a good idea to replace the soft pliable mounts for the oil tank when you R&R it - 41 or 42..44 in the above diagram. Likely hardened with age by now.

One of the many things that should be replaced 2-3 times per century on these cars.