Has anyone every replaced their engine oil cooler line? I bought my car a few weeks back (1982 diesel turbo) knowing this needed replacing. The leak has gotten worse so I want to do it now. Any advice or experience?
Do it sooner than later. Complete PITA, take pics before. You will probably need heat if they are very old. Be VERY careful on the oil cooler, the aluminum threads will strip. You will need to wrenches of the appropriate size (forget which one was which). Don't try to shortcut it, lifting the engine is the only way to go. Dont forget a 2x6 under the oil pan when jacking it up.
Do them one at a time, and it doesn't matter how you take them out, they will seem to refuse to go back in the same way.. all of a sudden they'll go in, and you'll scratch your head wondering why the last 8 times you tried that angle it didn't work. The job totally sucked, not because it was difficult, but because it seemed like the car was fighting back.
It's not so bad, but then I had to do it three times before it was right. First time I got it all done, started the engine and the top line had a bad weld at the fitting near the oil cooler and was squirting out oil. Second time the bend on the replacement line was off just enough so it would not fit. Third time was the charm. It took days because of waiting for the parts. All and all about 6 hours work. If your motor mounts are of unknown age, now would be the time to change them as well as engine shocks.
But you really should do both lines at the same time! Jacking the engine up isn't necessary if your engine mounts are in good shape, but it does help. The only thing I would recommend you NEVER do is to modify your oil cooler hoses by trying to take a short cut and fabricate new hoses by band clamping them or some other mod. If you do this, it will be just a matter of time before your going to blow a hose and then you will be looking for a replacement motor!
Tip: It will be impossible to replace one line without replacing the other! Ask me how I know this! Car wins and owner gives!:bowdown: Good luck! Expect this to reasonably take your Saturday, but it is worth it.
If you strip the threads on your Oil Cooler nipples Mercedes has steel repair nipples. However, you need the right sized drill, tap and a Hacksaw. The Steel Repair nipples themselves are inexpensive. Oil Cooler Repaired - ShopForum
Forget about the last picture in the above theads sequence. When old nipples are cut off the Hex portion as in the 3rd pic should be let so that there is enough meat for the tap to thread into.
The person who took the pics decided at his own risk to use his repair the Oil Cooler with the hex ripped part off any way and ended up with only a few threads to hold the repair nipple in.
One of the members of another forum suggested that a Dremel tool with a Cutoff Wheel could be used carefully to cut a slot through the nut or the same thing done with a saw. To, preven the threads from stripping.
I lost 2 threads on my oil cooler nipple when I removed the upper Hose Nut. A piec of the Aluminum from the Oil Cooler Nipple Threads stuck to the Nut and cut up the threads as I backed it out.
Sorry to resurrect an old thread, but I'm on my third W123. The first two were 300D models, and my current money pit is an '85 300CD. It's due - overdue, really - to have the oil cooler lines replaced.
With my first one, I replaced them while I was replacing the radiator. The engine mounts had been replaced previously, and were still in excellent condition. With the radiator out, I simply removed the bracket and engine shock and voila - piece of cake. I used this method on the second, and again - a breeze.
Now, if I had just taken pictures... I'll do that this time, and post them here when completed.
One tip for those doing this job is to soak the fittings for a few days with PB Blaster or some other penetrating oil to make removing them easier. I did this job on my old 300D and it is by far the most miserable job I have ever attempted on a W123. If I ever own another car with the OM617A motor I will be farming this job out. Took too long and too frustrating.
"I used this method on the second, and again - a breeze."
Did you remove the radiator second line?
If the motor mount carrier is removed do not remove the lower oil cooler bracket to engine.
Remove motor mount and engine shock absorber.
PB the motor mount carrier bolts. Two are difficult access. Try 17mm deep socket.
The messy part of this method is removing the adjacent power steering line so that the carrier will clear. It is messy.
Once the motor mount is out, clearance is not a problem.
PB, PB, PB the oil line nuts. I used an 8 inch adjustable bottom fitting.
Use heat judiciously on the lower oil cooler in line and PB.
Clean oil cooler fittings before install. Use antisieze.
You may need a Back-up Wrench to keep the Fitting on the Oil Filter Housing from turning out or getting over tightened when you remove and install the Stock type Oil Cooler Lines.
Unless you are lucky and have a Wrench with a thin head you will need to thin the Head on a Wrench. I am not sure but I think it was a 24MM Wrench.
If you go to the Mercedessource site you will see a cut down Combination Wrench used to get into the hard to get places to turn the Hose Nuts. If you want you can make one of those yourself.
I My Case I used a Large crows Foots on a Breaker Bar to turn the Hose Line Nuts when I removed My Oil Filter Housing and when I removed some Oil Coolers in the Junk Yard.
I usually get flamed for posting this, but harbor freight has this set of wrenches I have one in my trunk. The wrenches are thin enough to fit the oil cooler nipples and lines....nice set of wrenches too in my eyes..
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