M117 lower oil pan replacement

One of the things I noticed when I first changed the oil on my 560SEC was the dent in the lower oil pan.   Presumably it hit a curb or rock at some point.    It was also leaking.   the dent was likely too small to interfere with the oil pump, or oil pickup but I wanted to be sure.   The M117 lower oil pan can be changed without removing anything else.   It made sense to replace it with a new one to make sure there is no impact on the engine and to stop the leaks.

As it was about time to change the oil, it seemed like a good time to change it.   There are 20 little bolts holding on the M117 lower oil pan.    Not all of them are the same length so  I built a template to make it easier to replace them.  These bolts have a small allen head.   One of them near the A/C compressor also has a nut on the other side.

It was not difficult to remove the oil pan.  Whoever had installed it last time had not used a gasket.   This is probably why it was leaking.   Once I removed the pan, I was interested to see what was waiting for me in the bottom of the engine.   The good news is that there was no sludgy oil or pieces of bearing.   The bad news is that there was a quite big lipped washer in there.   I have no idea where it came from.   I have posted on a few forums to see if anyone can identify it.   Not surprisingly, there was also a small piece of chain guide.   When I had the timing chain replaced, one of the guides had already broken.   Please comment below if you know where that washer might have come from.

With the M117 lower oil pan removed, I could see into the bottom of the engine.  This included the oil pan, bearing caps, crankshaft etc.   I could see some scoring on the walls of the upper pan.  I am not sure if this is previous damage or how these engines come.

Installing the M117 lower oil pan is not difficult.   I used some gasket sealer as well as the gasket.   It would have been helpful to have an assistant though.   While I cleaned the surface of the upper oil pan thoroughly, just as I was putting the new pan on, a drop of oil came down out of the engine and contaminated my sealant and gasket.   I hope it doesn’t make a big difference.  Having an assistant would have allowed that person to quickly hold up the pan and me screw in the first couple of bolts by hand.

The torque setting is 11nm, but for some reason by torque wrench didn’t seem to be working, so I did it by feel.   Not ideal, but hopefully ok.   I will re-fill it with oil and change the filter tomorrow.   Hopefully no leaks!   While I was at it, I put in a new drain plug and washer.

while I was in the area, I also replaced the steering shock.   It is literally a 5 minute job.   Two 17mm nut/bolts and its off.   Looks blue thread locker was used before, so when replacing the bolts I used some as well.   The old steering shock had no resistance at all, so I am glad I changed it.     Slowly I am getting through all the jobs needed to turn this 560SEC into a nice car.