Mercedes engine mounts replacement

This weekend I replaced the two front engine mounts on my 1991 Mercedes 300D. The driver side mount was completely destroyed by several biodiesel leaks from the fuel lines that run directly above it. The passenger side mount was probably OK, but I replaced it anyway. I spent about $100 on the parts and another $40 on various drive extensions and a set of metric hex keys. My mechanic’s estimate for this job was $400. These are the tools I used:

  • 1.5 ton engine hoist (thanks, Al!)
  • 8 mm hex key (plus a 12 inch long pipe for leverage)
  • 17 mm ratchet with 10-inch extension bar and a jointed extension
  • WD 40 spray
  • jack and ramps to get more clearance
Mercedes on ramps with engine hoist

Mercedes on ramps with engine hoist

The whole procedure took me about 4-5 hours (2-3 on Sat and 2 on Sunday) incl. taking pictures and replacing a fuel line. Getting the engine hoist connected, the engine lifted and the mounts disconnected took about 2-3 hours. Mostly it took me that long because I had never dealt with an engine hoist and I was very careful. Removing the four bolts was also a bit tough. The top bolt on the driver side was actually loose, but difficult to get to. I ended up removing a fuel line (and replacing it later) to get to it, using a jointed extension and a 10-inch bar extension.

driver side mount from above

driver side mount from above

The bottom bolt on the passenger side was really tight and I used a piece of pipe with the hex key to get it loose.

passenger side mount from below

passenger side mount from below

After I finally got all 4 bolts out, I removed the old mounts and slipped new one in. I cleaned the bolts with WD40 and threaded them into the new mounts (that took a while – especially with the heat shield). Then I made sure that they were orientated correctly, with the notch at the top in the groove. Then I lowered the engine sloooowly onto the mounts and tightened the bolts. Then I removed the hoist and installed the new fuel line. When I cranked her up, it was so nice – no shake, rattle and roll and more, just a mellow hum from the engine.

More pictures below.

passenger side mount from above with heat shield

passenger side mount from above with heat shield

engine mount

new mount on passenger side – no heat shield yet

old and new mounts

old and new mounts

 

 

 

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