1976 W115 240D oil Filter leak problem

[matthewc]

Hello All,

This is my first post in a long time. I just acquired a 240D with unknown mileage and decided to change the oil and filter. I drove a few the car a few hundred miles before this--there were no oil leaks. I changed the oil and put in a new filter (very messy) but finally got the canister bolt screwed in fairly tight (if anyone knows the torque value for the oil filter canister bolt, I would be much appreciated), took it for a brief test ride . . . and no leaks.

Then I saw the "pre-filter" on my workbench--I had installed the filter without putting the pre-filter back on the bolt shaft. I took the canister/filter off again, put the plastic pre-filter on, correct side up and screwed it down pretty tight, but not too tight. I started the car, started backing out of the garage and then noticed at least a gallon of oil on my garage floor. It spewed about 1 gallon of oil in about 30 seconds.

What did I do screw up? I don't know-BUT I did not install the ~22mm inside diameter copper ring that came with the Mahle oil filter kit (I couldn't figure out where that was supposed to go). Also there was a dent on the lip of the top of the canister (which I've since fixed and it was actually there before I did the oil/filter change when there was no leak).

But most weirdly there is a synthetic band (not an o ring) that goes around the top of the canister lip on top of the big rubber o ring--this was there when I first removed the canister so I kept it back on. But I don't know if it should be there--I don't see it in exploded oil filter parts diagrams for W115 engines.

Any ideas? I have pics https://imgur.com/a/6fZDi?gallery

Thanks in advance,

Matthew

[cooljjay]

Confirm all the peices are together correctly....I see a bend in your canister....you need to fix that...

[matthewc]

Thanks CoolJJay! That diagram was what I was looking for.

I reassembled the filter into the canister with the spring in the correct orientation this time. I also left off the synthetic band that was under the big rubber o ring.

This time, I made sure to push the oil filter housing up snug and centered against the Filter top before tightening the bolt with my fingers and then the 17mm socket to 30 ft/lbs.

Long story short--no leaks.

To anyone doing this job the first time I would advise them to do the following along with your suggestion:

1.Take your time.
2.Clean all the black oil off everything before re-assembling so you can see what your doing.
3.Jack the car up--at least the left front quarter.
4.Go slow.
5.Double check the order and orientation of the oil filter parts assembly before getting under the car.
6.Wear clothes you don't like and want to get rid of when doing the job.

cheers,

[joshhol]

On my 115 it's very easy to cross thread the main filter bolt and get that thing snugged down with a huge gaping space where there shouldn't be. Not sure of the torque spec but you don't need to go crazy. Tight but don't force it.

When you are putting it back in, always run your hand up around the filter canister and feel that its sitting flush with the top.

I watched some guys at a 76 station do the very thing you described when I was young and not changing the oil yet. Fortunately they test started it for leaks before just assuming it was fine.