Okay, I am about to do my first oil change on the 85 300 SD. I had ordered the 2 O rings that go on the shaft that goes through the oil filter cartridge.
Now I can only find one of them. I may not have to replace both but does anyone have a P/N I can get from say NAPA if I find the current O rings destroyed. Or If for some reason I can not what would be the outcome of using just one ( also which one is most important) for a few days.
Thanks

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92 500E Silver 66k
82 Porsche 911SC 84K
68 Cadillac ( Gone Now )
03 Suburban Z71 200K
85 300SD 217k From Original Owner ( Dad )

I think most here do not change those unless they look bad. I wouldn't worry about them too much, unless of course they are bad and/or are missing.

I had the same situation recently. Cut the old ones off and didn't have the correct new parts.

Advance has them for $1.00. They are 10mm OD x 6mm ID.

Thanks guys. That was fast. The rings may be okay but the oil has been changed by non MB shops before so I wanted to be ready just in case.
I am certain as soon as I am done I will find the 2nd O ring I ordered.
Thanks again
Alan

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92 500E Silver 66k
82 Porsche 911SC 84K
68 Cadillac ( Gone Now )
03 Suburban Z71 200K
85 300SD 217k From Original Owner ( Dad )

I just measured a new one from my stock. It's 10mm OD x 6mm ID
P/N 015-997-94-48

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82 300SD 202K
82 300SD 233K
83 300TD 340K
82 300TD 98k euro (parts on the hoof)
85 300TD 282K
83 300TD 197K

Both O-rings are 6mmIDx10mmODx2mmW

Autozone sells a Metric O-ring assortment made by Dorman for less than $8.
Dorman 172 piece O-ring Value Pack #799-450
In it are 24 of the 6mmIDx10mmODx2mmW O-rings that you need for the bottom of the Oil Filter Stem: enough for 12 Oil Filter Changes as you need 2 O-rings each time you change it.
However, some people lncluding myself use 7mmIDx11mmODx2mmW in the Upper Groove (where the shaft is larger). If you do that you have enough O-rings to change them 24 times.


The 10mmIDx17mmODx2.5mm in the kit fits the bottom of the Filter Bolt; you get 24 of those in the kit.

Hunter said that Harbor Freight is selling a Metric O-ring Assortment (updated from the one I bought about 3 years ago); but, I do not know what sizes it has.

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84 300D, 82 Volvo 244Gl Diesel

I concur with these numbers. Since we have a couple different sizes listed, I also just measured one from my stock. 10mm OD x 6mm ID x 2mm thick.

I need to get one of the o-ring assortments. Handy to have around.

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This is how one of the popular internet seller has it listed:
0159979448 Bruss Oil Filter Gasket; For Tube at Oil Filter Canister Lid; 6x10x2mm
2 per car $0.38

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84 300D, 82 Volvo 244Gl Diesel

As always fast, accurate information here. I changed the oil and both the O rings were good with no flat sides on the outer circumference so I left them alone. I will be changing the oil again in less than 30 days and will replace the O rings then.
Thanks
Alan

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92 500E Silver 66k
82 Porsche 911SC 84K
68 Cadillac ( Gone Now )
03 Suburban Z71 200K
85 300SD 217k From Original Owner ( Dad )

Thanks for the correction. I probably shouldn't rely on my memory anymore.

At least some previous owner knew to change them.

Mine were not only flat but as hard as a rock. They cracked off when I pried on them.

Replacing those 2 O-rings sometimes brings up you hot Idle Oil Pressure a little.

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84 300D, 82 Volvo 244Gl Diesel

Same here. I didn't so much pry them out as chip them away with the point of a screwdriver.

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1981 Mercedes 300TD, 1994 Honda Civic Del Sol
http://mefi.us/images/fuelly/smallsig-us/67195.pnghttp://mefi.us/images/fuelly/smallsig-us/103885.png

That's usually how it goes for me too. I replace mine every few oil changes to keep them from getting this way. I check them every time though.

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I've changed quite a few and most crumbled apart when I preyed them out. I have never seen any difference in the oil pressure behavior before and after new O rings which would mean the old ones were doing the job, I would think??

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

On mine the hot oil pressure at idle went up slightly, and the gauge needle no longer vibrated. I agree it's not a huge difference.

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1981 Mercedes 300TD, 1994 Honda Civic Del Sol
http://mefi.us/images/fuelly/smallsig-us/67195.pnghttp://mefi.us/images/fuelly/smallsig-us/103885.png