Critter

Looking for info on DIY replacement of the O rings on the drive side of block for the oil cooler lines.
Twin lines run from the block to the front cooler.
Located above the AC compressor and in a terrible spot.
Anyone had success with the O ring replacement
Just to clarify they are located on the engine block two aluminum oil lines held on with male torx screws, one screw per line

Critter

No one ever change these O rings ????

Rocman8

Remove belt and unbolt the AC compressor

hachiroku

mine have been leaking for a year now...gonna have to bring her into the shop this week or next as it's gotten worse.

picked up o-rings a few days ago...they were something like $11.56 each. was discounted to $9.xx after I asked for a better price.

EvoTechnik

Id like to know as well... I have the same issue.

hachiroku

https://mbworld.org/forums/w211-amg/...only-find.html

had my buddy replace these as well as replace my lifters and head bolts. it is not an easy job as you have to remove all front engine covers, and reseal the upper oil pan. at this point my upper oil pan was also leaking so he had to reseal both upper, mid, and lower pans.

its a lot of work for a DIY'er

VII

I need to do this too...
There is nothing in WIS about this, let's see if unbolting compressor works...

hachiroku

from what i recall from my mechanic...unbolting the compressor will make things easier but isn't absolutely necessary. not unbolting it does add quite a bit more work from what i recall.

Yuille36

Unbolting definitely frees up room to get your hands in there. I along with my mechanic replace mine last year.

VII

Yes un bolting the compressor was enough for access along with the removal of the power steering bracket.
Also had fun removing the line bracket bolt which is directly over the from subframe.

Rovel

Did replacing the o-ring on the cooler line fix the oil leak? I have the same issue.. very minor leak. The mechanic told the oil cooler coming off the block was leaking. Also, can you share more about what it takes to replace it? Thanks.

Yuille36

I replaced my oil cooler o-rings years ago due to a leak. These lines are under a lot of pressure, so replacing them is key. For replacing them, that was mentioned in a previous post. Plan to spend several hours in labor.

E63007

I bought those Oil Cooler Oil Rings years ago but never have had the occasion to do them, until now, that is... I am in process of replacing my Radiator/Condenser and Compressor, and after removing the Coolant Reservoir, I can clearly see now that P/S Pump bracket in the way! I should have done this back when I had both Heads off to be rebuilt!! Nevertheless, since I have the fan out and will have the new Rad/Condenser soon, I will have enough room to remove the Compressor. After all, WIS states that after disco'ing the Compressor, one must drain all oil so that you can remove the compressor from below after disconnecting the cooler lines in the bottom front side of the engine. With the fan, Rad and Condenser out of the way, I should definitely be able to get her out!! Then to get those Oil Cooler Rings installed, all you gotta do is remove the P/S Bracket (which I had to do when removing the Head!) and then unbolt what appears to be the Cooler Lines Bracket which seems to affix them to their position. As for the "Line Bracket Bolt", not sure what that is, but maybe that's a reference to the E55?
06/14/21-update- I did manage to get out the Compressor without having to drain the oil from the Compressor itself, and disconnect the bottom of engine Oil Cooler Lines. As I mentioned above, I had ordered Oil Cooler Rings years ago but after removing the Compressor, I replaced the Oil Temp Sensor, which was so brittle the plastic top containing the electrode broke off!, and then was able to "pull out" one of the Oil Cooler Lines from the Engine only to find that the O-Rings I had bought were NOT for that side but for the side of the tube connecting to the rubber hose which then connects to the Oil Cooler itself!! I guess that's what you get sometimes by ordering a mass amount of parts from OMB MB resources online where they just guess what part might be the correct one if they don't have the item number you provided in stock!!! At first glance, they looked like they might be the right ones but after removing one of the Tubes from the Engine and carefully taking off its O-Ring with a right angle scratch awl/pick it turns out that the ones I had were obviously NOT the correct O-Rings! So after entering in the Part No in the EPC, it pulled the WIS Page showing where that O-Ring fitted, as mentioned above!! I'm sure glad I double checked!!! As for removing the Oil Cooler Tube from the Engine, I used one of the plastic "Lever Tool's included in a pouch whereby the tool has a U shaped "Hammer like nail remover" that I fit around the Rear Tube and used the forward pipe as a pivot. The tool itself bent because it was plastic but it lifted the tube out of its recess enough to then get a screwdriver (with duct tape on its tip to protect from marring the tube!) between both tubes to pry it out. I'll similarly use a small block of wood to place up next to the other Tube and lever it off the engine with a small pry bar. Working from underneath with the Compressor out of the way allows you just enough room, but not much more!!! Also, for those of you that have bought a "new" Compressor, be sure to Add the required amount of PAG Fluid to it as well as to the Condenser even if the Seals show some PAG Fluid. I talked with a Mercedes Tech today regarding this and he confirmed as much to me, specifically that they just put enough PAG Fluid in to keep it lubed for transport/Storage. But then Denso states “All” their compressors on this platform of the multiple piston variety are completely filled and that one is unable to drain the oil by simply turning it upside down and turning the pulley???

Aussie Eddie

Can someone kindly provide the part # for the o rings. My indy has confirmed a leak where the oil cooler line attaches to the block but I've struggled to find the correct #. Is it the same o ring for the oil line and oil return line? Thanks in advance.

farkis644

Does anyone have the part number for the o-rings please? I am desperate

Yuille36

For the M156 community, the oil cooler o-rings that are located in the block are 012 997 5648 I believe that these are also the same ones that are in the oil cooler itself.
Regardless if you order these, you should be good to go. A quick google search will confirm.

Aussie Eddie

Can confirm that's what I used for the job. Took my mechanic about 4 hours in total if I remember correctly.