Changed Upper Oil Cooler Line 300SD - PAIN
 

I just finished changing the upper oil cooler line on 1983 300SD 617.95x engine.

Not a really easy thing to do, should have done it when I was doing motor mounts.

Previous Owners mechanic wrenched the oil line down so hard I had to use two foot pipe on wrench to get it loose. What a shame.

Leaked a lot at the oil filter housing end of line, put the drain pan here.
( I did not drain the oil, had just done oil change when I realized it leaked).

Ended up unbolting motor mount and removing engine shock absorber
on driver side. Removed air cleaner housing before jacking up motor at
oil pan with piece of wood to distribute load so that air cleaner housing
would not contact body and break air cleaner mounting bracket.

With some finagling was able to get lines changed.

I did search the forum before doing this to see if anyone had any advice.
Did not find anything I could use, but I am here to say that it was possible.

300d?
 

Would replacing the oil line be easier on a 300D? I would like to change both of my lines. Is the lower line any easier?

Thanks,
Keith

I did both cooler lines on the SD about six months ago. That upper line is definitely a PITA. I sat and thought about it quite a bit and decided that I could thread the cooler end through the narrow opening underneath the mount. Of course, this required the remainder of the hose to be pointed toward the ceiling for most of the attempt.

Furthermore, I heavily taped the end of the tube because of the abuse it was going to see during this process. There was a point where it was stuck in the opening and there was some doubt if I could force it through without damage to the end of the tube. But, perseverance prevailed and one massive push got it through and around the bend up to the cooler. From that point forward .......it was all downhill.

The job took the better part of a day........including very carefully removing the fittings on the oil cooler.

I replaced the lower oil cooler line on my 83 300D. U do not need to undo the motor mount, just unscrew the lower motor mount bolt.

1) Drain engine oil.
2) unscrew both ends of the cooler line. Be ready to collect any oil in the cooler line that will flow out
3) The cooler line is held at 2 points - at the compressor and near the motor mount. If memory serves me correctly, there r 2 bolts (13mm) that hold the lower bracket that holds the cooler line near the motor mount. This L shape bracket has to come off or u will not have enough room to snake the oil cooler line in.
4) Unscrew the bottom bolt of the motor mount.
5) I used a 2" x 8" piece of wood that was a bigger than the oil pan ( about 2" excess on all sides. place that under the oil pan. It has to be centered on the oil pan. Place ur jack under the wood, at the center of the oil pan. Lift the jack until the car is about 2 inches at the motor mount (near cooler lines). Then snake the oil cooler line out, coming out from the top, front, near the oil cooler. If u need a little more room, carefully jackup a little. Snaking in cooler line is the reverse.
6) Button up is reverse.
7) Watch the oil level when filling up engine oil. It takes more than the norm - Can't remember but could be 8.5 liters. Pour the usual seven and then pour in the rest in stages, checking the dip stick. Start the car for a couple of seconds, switch off and check the oil level, just play it safe.
8) U should be done in about 2 hrs or less, factoring a beer and sandwich break.