95 540 oil cannister cap problem

[bimmerlee]

I'm having a problem with the screw-on cap on the oil cannister for my 95 540. The top of the cap is crumbling and I've tried two new caps from BMA. Neither of the new caps will screw all the way down. I've talked to my local mechanic and the people at BMW with no success at finding a solution. Anyone got any ideas?

[Bill Marshall]

Ensure you have fitted the large o ring on the cap threads underneath the shoulder of the plastic cap - if not I don't believe you can thread the cap all the way down. Bill Marshall

[DueyT]

As Bill noted, your o-ring might not be properly seated. When you screw it down, it will be relatively easy for most of the way, then when it appears to be ~1/8" from all the way down, it seems to get stiff...keep going through this resistance as that's the o-ring being squished into the canister housing. You'll find it gets easier after that, but not as loose as when you were first screwing the cap in place. Final torque should be no more than 25 N.m or about 18-20 ft-lbs.

Cheers,
Duey

[tim]

If you oil the o-ring before tightening, you can get it almost all the way down without a wrench. It does not rely on torque to make the seal. It the only housing that they used on the 540, So it's unlikely you got the wrong part twice (although I've done it! <g>)

Since you took it a BMW mechanic, I'm guessing you have the o-ring in the right place.

Another thing to consider is: which oil filter do you have? I seem to recall that there are two designs that were found on the 540 that have slightly different specs. One, like mine, has a plastic spindle in the middle of the filter housing. The filter has a plastic top. When the filter is put in, it pushes down to the bottom, but if you push harder it goes down a bit more, and when the cap is replaced, it holds it down at this lower position. The other had a metal end on the filter cartridge which required turning it in the housing until it engaged the flange at the bottom. I thought the dealers changed the old style out on most cars by installing the plastic spindle in the housing as part of a recall or something. Perhaps your problem relates to one of these issues?

Probably not it, but a thought.

[632 Regal]

you may have the wrong combonation of filter, insert and that would definetly cause problems. The dealers are dumb as **** when you have a perplexing problem that is simple. do you have the new style insert that goes into the filter? Winfred says they look like a dildo.

[bimmerlee]

The problem show up before it even gets to the o-ring. Don't think it's the filter. Got it from the dealer and I know the parts guy personally..pretty sure it's the right one. I had to put the old cap back on using the new filter, so I'm sure it's the right filter. I don't think I could get the wrong part twice either so I'm really stumped on this.