617.951 vs. 617.952. - PeachParts Mercedes-Benz Forum

alfa 75 · #1 12-21-2007, 12:46 PM

What's the difference between these two engines? Aside that one was used in the W123 and one was used in the W126?

kerry · #2 12-21-2007, 01:03 PM

Different oil pressure gauge systems for one thing. 123 is mechanical, 126 is electrical.

#3 12-21-2007, 05:32 PM

That and the engine mount arms.

The engines are functionally identical.

jparker164 · #4 06-03-2008, 05:37 PM

I'm hoping to replace the engine in my 300SD with a om617.952 that came from a station wagon. It's SLS system has been disabled already. Anyone know what other problems I may have?

dieseldiehard · #5 06-03-2008, 06:01 PM

Quote:

Originally Posted by jparker164

I'm hoping to replace the engine in my 300SD with a om617.952 that came from a station wagon. It's SLS system has been disabled already. Anyone know what other problems I may have?

Seems like I ran into this before. The exhaust manifolds are different if Federal vs CA car so plan on keeping the old manifold it will fit no problem on the wagon engine. Your talking 123 into a 126 chassis, right? A 116 chassis engine may have a different oil pan and turbo return
The mounting arms can be swapped. Should not be a problem with the SLS pump unused You can also blank it off if you wanted to make a plate for that purpose.

#6 06-03-2008, 06:04 PM

My understanding is that there is a plate available for one of the gasser engines (with optional SLS) that will bolt on to the 617 SLS pump.

LUVMBDiesels · #7 06-03-2008, 08:00 PM

I did that swap although from a 300D to a 300SD.

Here are the differences:

AC compressor -- if your compressor has freon in it, unbolt the compressor from the engine and tie it up out of the way. You will not have to open the system to do this

Engine mounting arms -- swap them for the ones on the SD engine

Oil filter assembly -- the W123 assembly will NOT fit in a W126 (I tried) Get a new Oil Filter Housing gasket from the dealer (about $1.80)

Air filter housing -- the W123 has a smaller fresh air opening and it will not take the tube from the front of the car.

Now would also be a good time to replace your alternator with a Bosch AL129x 115 amp unit.

The accelorator linkage and the bowden cable will fit correctly.

You could also remove the EGR valve and the black box "stuff" on top of the valve cover...

You might consider taking the engine out of the SD with the transmission attached. It is way easier to put the engine in as a unit with the tranny then to try to bolt it together while they are in the car (I did that mistake too)

Just take your time and it will all work out.

Good luck