O Ring Woes

[RML]

Ok, so I changed my oil last week and discovered that there were no O Rings on the spindle connected to the housing lid. So a fellow member, Marty, (NHDoc), was kind enough to send me a set of O Rings. So I happily went out to the garage tonight to put them on. Well, I was not sure if they are supposed to fit in the little grooves in the shaft, or up against the shoulders that are created by the increases in diameter in the shaft. I first put them in the grooves, put the cap on, and found that I could not get it all the way seated. So I pulled it out, moved the O Rings up on the shaft to the shoulders, and using the assistance of a rubber mallet, seated the cap. I thought I would pull it out again to see if they were still in place, and like magic (black magic), they were gone. I have heard forum members say that you only have to change the O Rings when they get brittle, but I am losing mine!

So where are they supposed to sit? And do they come off every time you do an oil change? Are they plugging something up or just ending up in my oil pan? Should I try to fish them out somehow?

Richard

[TMAllison]

O-rings should come with the oil filter that you purchase. Mine always have.

There are 3 of them. The small one goes on the very end of the plastic stick protruding through the paper filter cartridge in an obvious groove and the larger one goes goes toward the top of the plastic stick in another groove. The 4" diameter oring goes on the cap itself to seal it to the filter housing when you tighten it back down. You do need to lean on the cap and get everything "seated" in order to have the threads on the cap to get a bite. I'd lay off the mallet....

No, they should not come off and in fact are difficult to remove as they are 1) pretty tight, and 2) really slippery lil buggers.

I dont know where they end up when they fall off?

[tangofox007]

Originally Posted by TMAllison

O-rings should come with the oil filter that you purchase. Mine always have.

I have been buying MB filters for 15 years and have never seen an oil filter that came with the small o-rings. That includes at least six different brands.

[TMAllison]

Tango - Are you talking about an E300 which uses 3 of them, or another model which doesnt use them....?

*edit* Sorry both tango and rick....saw Martys name and orings and missed the fact the poster was discussing a 300D. Was thinking of the E300.

[kerry]

I assume we are talking 123. I believe the o-rings go in the grooves. I have no clue where they went.
I've never gotten any o-rings with filters for the 617 engine.

[RML]

Terry: You must be talking about your 99 E300. I should have been explicit and specified that I am working on my 84 300D Turbo. My spindle is not plastic, it is metal. I did get a large O Ring, 4" sounds about right, that goes on the cap and seals it to the housing. My filter did not have any other O Rings included.

[TMAllison]

Rick - Yes, I was mistaken.

Marty is going to be in your neck of the woods tomorrow getting his car....make him show you where it goes. He owes you a little dirt under his fingernails.

[RML]

Originally Posted by TMAllison

Marty is going to be in your neck of the woods tomorrow getting his car....make him show you where it goes. He owes you a little dirt under his fingernails.

Terry: Yes, I will see Marty tomorrow afternoon. I'll pick his brain, but I wouldn't have the heart to send him off in his new W116 with oily hands. Wow, is that car nice. To have taken better care of it, the PO would have to have kept it in a museum.

[JimSmith]

The two small O-Rings go into the grooves on the shaft. They get old and brittle, losing their ability to seal the "pot" of oil with the filter in it, which allows the unfiltered and filtered volume to drain into the sump at shut down. means longer cold operation until oil pressure builds (you have to fill the "pot" again, first) and you get flow to the vital parts. The W210 filter comes with new O-rings for these positions. The W123 doesn't, and many people don't notice them, and never change them. Jim

[charmalu]

RML, You do provide some of those pretty blue manly rubber gloves
don`t you, you need to be the gratious host.

those little O rings do get kind of hard after 15 to 20 some odd years. I
thought they were suppose to be hard plastic, until I got some new ones.

maybe the filter maker should keep the little steel washer, and throw in a
couple O Rings.

Charlie

[toomany MBZ]

None of the filters I have purchased came with those little O rings, just two washers, one of which is useless, and a large O ring for the cap.

They do fit in the grooves, help with idle pressure, and help prevent cross contamination.

[RML]

Upon further discussion with Marty, I have learned that what I was observing to be dark metal rings are actually the very old and very hard O Rings. I started to pry at them but thought better of it, as I have broken my share of things mechanical by applying too much force. In this case, it will be warranted.

Richard

[300GD]

RML - just had a very similar experience in replacing those o-rings in my 300GD (same engine). Mine had also taken on the appearance of hard plastic. I figured anything thin enough to stick into the grooves - like the tip of a knife - to try prying them out would just break. I ended up using a Dremel with a cutoff wheel. You have to take care not to damage the grooves though.

And yes, I think I also managed to drop one of the new o-rings into the oil filter housing. I couldn't locate it anywhere. If I'm lucky it found its way to the sump. I hope to discover it when I drain the oil.

[RML]

It all makes sense now. Marty flew in and picked up his car this afternoon and left me a few more O-Rings, which I will put on this weekend. I will break out the old hard and brittle ones and it will be obvious now where the new ones go.

I tried to see if I could fish out the ones that came off, this morning before I left for work, but they were long gone. Ahh, the feel of black diesel oil on your hands early in the morning, what more could you ask for.

Richard