A guy on the CumminsForum had good reports about this. HE started with black oil and cleaned it up. I'm not sure if he took oil samples.

We Filter It!

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

My thought is why bother when you can get a half a million miles with dino oil and regular oil changes?

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Len
'59 220S Cabriolet-SOLD and living happily in Malta
'83 240D 351,500 miles original owner-SOLD
'88 560SL 41,000 miles - totaled and parted out
https://sites.google.com/site/mercedesstuff/home
'99 E300 turbo 227,500 miles
'03 SLK320 40,000 miles - gave to my daughter
'14 Smart electric coupe 28,500 miles
'14 Smart electric cabriolet 28,500 miles
'15 Smart electric coupe 28,000 miles

If it could remove the soot from the oil it would do well in our old MBs, since soot loading is what seems to dictate the OCI.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Think it would be hard to add a second oil filter onto the w123 but it would be nice....because of the soot factor.....I have so much built up gunk in my engine, I have to change the oil every 1000-1500 miles.....I can tell by the pressure gauge.....and the weight of the filter when I remove it...

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If you're putting that much soot into your oil you've got some other serious problems...like streaming injectors or bad timing. Since you're running veg oil I'd look into it... a streaming injector is like a blowtorch... it will cut right through glow plugs, prechambers, and pistons

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

I installed Dual Oil Filters on my 2000 Dodge diesel Dakota mainly to add some oil capacity.

I used this kit:
AMSOIL General Use Dual Remote Oil Bypass Unit

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
No longer selling Cluster Needles Paint
No longer selling New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

Anatomy of a Frantz toilet paper bypass oil filter

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

There was a fella on TDI club who did research on bypass filters and found only the toilet paper type removes some soot (not all). The centrifuge type filters does not remove soot and was found to remove some of the additives. Not a good thing.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Adding A Bypass Oil Filter works; it does not matter what Engine you have.
I have one on My Car
Bypass Oil Filter Setup, 617.952 Diesel911
Bypass Oil Filter Setup, 617.952 - PeachParts Mercedes ShopForum

ForcedInductions Amsoil Bypass Oil Filter installation
By-pass oil filter install

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84 300D, 82 Volvo 244Gl Diesel

Nothing you can do will keep the Oil from turning Black on the older Mercedes.
For one thing according to the tech Manual there is a one liter difference between a completely dry Engine that never had Oil in it and the amount needed for a Oil changer.

There is always dirty Oil left inside of the Fuel Injection Pump and at the Bottom of the Oil Cooler; on the 617.952 Engines.

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84 300D, 82 Volvo 244Gl Diesel

This is the tdiclub post I was referring to where migbro said that only the toilet paper filters remove some soot, the Amsoil does not.

forums.tdiclub.com/showthread.php?t=371713

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Direct Injection Diesel Engines do not produce the same amount of Soot the Indirect Injection Engines do.

My Volvo Diesel that has a different type of Precombustion Chamber and with a rebuilt Block does not produce the Soot the Mercedes does.
And, do a Valve adjustment on the Volvo like ever 7 years and I do not routinely check the Fuel Injection Pump Timing.
Also the Camshaft and Fuel Injection Pump are driven by Timing Belts that are more likely to be out of adjustment than the Timing Chain.

So it might be that the Amsoil Filter might remove soot from a Mercedes because there is more of it and the Soot supposedly clumps together.

If I picked the correct thread of mine in the previous post there is a pic of the Filter Element and there is clearly something on the outside of the Filter Element that got Filtered out. And, that particular Element is a 0.5 Nominal Micron Filter; and that is not as good as a 0.5 Absolute Micron of filtration.
So in My case the 0.5 Nominal Microns of Filtration is still way better than the 22 or greater Nominal Microns of the Stock Oil Filters.

And, if the Amsoil Ads are correct an Amsoil Filter Filters better than the one I have.

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84 300D, 82 Volvo 244Gl Diesel

Well, if anyone wants to try it I have oil filter relocation plates for the OM617 in stock. You can either remotely mount the stock filter housing and tee one of the lines to bleed off to a bypass filter, or just get rid of the stock housing altogether and run a complete aftermarket filter and cooler system.