I've been reading that I need to swap the oil pan, and one member mentioned taking the oil pickup tube from the 3.5L and taking it to a machine shop and having it machined to get it to seal against the 3.0L block. Any ideas there? Also, someone else mentioned swapping oil filter housings. Anyone who was done this W126 OM603 to a W140 car that could offer definitive insight? Doing it at a location where I cant have it out of commission for very long, and done want it in the way. Is there anything else? I'm aware of alternator, AC Compressor bracket...etc.

Thanks a bunch!!

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1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

The side sump in a 603.96 oil pan won't clear the W140 K-member so you need a .971 oil pan; possibly a .970 oil pan will work. I never bothered to confirm that the .961 pick up tube works with a .971 pan. I moved the .971 oil pan and baffle to the .960 block when I did the swap. My memory is very rusty but I might have swapped main cap bolts as well to be able to attach the baffle. If you swap oil pumps but leave off the baffle, use spacers between the oil pump arms and main caps to account for the thickness of the baffle.

You can keep the front dipstick from the 603.961 but you might have to recalibrate it. Assuming the .961 goes in dry, fill it with 2 gallons, run the engine to fill the oil filter, then check the level on the front dipstick. Call that the real MAX level which might or might not coincide with the actual MAX mark. If it's way off, try a 606 dipstick.

I don't know what you mean by machine the dipstick into the block. IIRC the .971 dipstick goes into the the driver side of the oil pan, not the block. Other US 603s have the dipstick tube pressed into the front cover so your .961 has front cover should have a dipstick tube. If I'm correct that that the .971 oil pan comes with a dipstick tube fitting (and a dipstick tube!), you have to use that anyway fitting the .961 block into a W140. If you go with the front dipstick arrangement, a .970 dipstick (and tube?) might be more accurate.

I didn't bother to compare .960 and .971 oil filter housings. It wasn't worth flubbing the exercise and saving the cost of a gasket to discover that the oil cooler lines don't line up with the oil filter housing. You'll probably make things easier if you pull the .971 engine with the oil cooler lines. I didn't and it was a challenge to reattach the the oil cooler lines to the oil filter housing in the engine bay.

IIRC the .971 has a loose bracket between the AC bracket and front cover. The .971 might have a couple of longer front cover bolts for that loose bracket.

Don't do this job in a rush. That's a sure way to mess up.

Sixto
87 300D

Not machine the dipstick, this is what he said about machining the pickup tube and the other concerns...

"Everything matches up except the oil pan. The cross member on your S350 is in the way. So, I had to take the oil pan and the oil pick up tube from the 3.5L and put it on the 3.0L. Take a look at the mounting of the two different pick up tubes. I had to take them to a machine shop and they made the mounting surface of the 3.5L pick up tube match the surface of the 3.0L pick up tube. If you do not do that you will not have any oil pressure. It only cost me $20. Mounted the modified 3.5L tube to the oil pump, put the 3.5L oil pan on the 3.0L engine and she has been running ever since. Let me know how it goes."

I also noticed a W124ish looking oil filter housing with the center hardware in the lid. By the way this engine is positioned way back toward the firewall that wraps over the top, I will have to swap that over also from the W140 3.5L to the W126 3.0L. Otherwise I wouldnt be able to get the lid off to change the filter. Not sure on the pan. I have 3.5L pans off 90 and 91 W126's though if they will work. Not really all that keen on re-installing the windage tray. Maybe using locktite on the hardware to keep them in place?

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1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

Hey Sixto, if your memory is that rusty, just let me if you need a refresh. I'm pretty certain Southwest flys from SF to Raleigh NC. I'll blow the reward points for the flight, and hotel stay, lol.

In all seriousness, thanks for the reply and tips. I'm printing all of this out for reference preparing for the swap weekend. I know you said don't rush, and I wont, but I can assure you, no doddling will occur either once this process starts.

__________________
1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

Oil pick up tube. I read oil dipstick tube. Memory is bad, eyes are worse

You can swap oil pumps for less than $20. At least I think there's enough room to remove the oil pump without pulling the front cover.

I'm 99.44% sure you can replace the oil filter lid and center post if you don't have to swap oil filter housings.

Sixto
87 300D

Man, I drove the W140 today with the 3.5L still in it. Wow is all I can say. I've had over 8 W126's short and long wheelbase, OM617 and OM603's, 1981-1991 models, and I still say wow. This car drove like a dream. I still love the 126's (and 123's for that matter), but this is a whole new level of smoothness, silence, comfort, ride, and overall feel. Very excited to get a new powerplant in it. I bet this will be the ultimate in comfort on the highway. I bought a W211 E320CDI to use on long trips to get over 40MPG, but the comfort and substantial presence I've been accustomed to feeling just isn't there, and everything just feels all plasticy, like most other recent model cars. Still an engineering marvel for economy, and power, and roadworthyness on the highway, and it feels worlds better than the W210 I had for a very short time interior-wise and fit and finish, but just not there vs. the older ones. That said, I was amazed at the way this car felt driving it. I understand they are over the top as far as complexity, but hopefully I can weather that to enjoy this one for a while to come.

__________________
1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

Interesting. That will save some time if so. Great to know.

__________________
1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

Another question...

Pulling and Installing a OM603 into a W140. It is easier to do while mated to the trans as an assembly? That's how I do W126's, but was curious if it was tighter in a W140. The way the engine sits further back inside the tunnel makes me wonder how easy the bellhousing bolts are to get to. I'd rather pull it as an assembly, but I can pull it separate if needed. Thoughts?

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1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

It's tighter as you say. The conduit for the starter cables are a bear to work around to get to the upper bell housing bolts. I bent it every which was for access. Unless you can slip the cables out of the conduit, it has to come off anyway to pull engine and tranny as a unit.

Sixto
87 300D

I think MBZ stuck a V12 in there and there is plenty of room on the sides to play around and that's nice when doing any engine swap BUT it's too tight for getting at the upper Bell housing bolts easily as 6/2 says also getting at the drain ducting is close to impossible with engine and trans in place.
. go for the unit R&R if you have the space, it's almost always easier in the long run....and this may be a longer run than you think...sounds like a fun project but i'm glad you are doing it and not me.
Good luck!

Drain ducting? That needs to be removed as well? Or just worked around?

__________________
1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D

you will see it on drivers side. it's easy to remove but almost impossible to install with engine/trans in...
at least on both my S350D's. 1993, 1994