Can I jack diesel engine to remove motor mount when other mount is bolted tight?

[HuskyMan]

The passenger side motor mount is installed, bolts are tight. 6mm allen head bolts and 8mm under carraige bolt are out of the driver's side. Question; can I go ahead and jack the engine up using a bottle jack (jack placed slightly off-center towards the driver's side of the engine) without fear of damaging the passenger side motor mount? Or, should I loosen the bolt on the passenger side motor mount before jacking?

[torsionbar]

I would loosen the other side.

[okyoureabeast]

Loosen both, also put a block of wood between your oil pan and the jack!

[engatwork]

^that is how I do it.

[MB140300SD]

I do them one at a time. Loosen one side, jack it up with a block of wood under the engine. Remove mount, replace. Lower engine and install bolts. Loosen other side, jack it up etc. Otherwise you may have a hard time lining up both sides at the same time.

[NZScott]

It might be worth pointing out to the newbies not to tighten bolts/screws all the way down until all of them are in, goes for most things.

[HuskyMan]

OK, I loosened the passenger side before messing around with the mount on the driver's side. Everything is back together, new Lemforder mounts and new engine shocks. Now, I have to work on the injectors, injector pump timing and setting the ALDA correctly so I won't be doing this job as often.....

[Skid Row Joe]

Originally Posted by MB140300SD

I do them one at a time. Loosen one side, jack it up with a block of wood under the engine. Remove mount, replace. Lower engine and install bolts. Loosen other side, jack it up etc. Otherwise you may have a hard time lining up both sides at the same time.

^^^^ This, is how I'm now trained by Mercedes-Benz, to do mine.

[jay_bob]

Well the official WIS procedure tells you to lift it from above using the lifting lugs on the engine when doing this.

But of course most of us don't have a sky hook in the garage so we use the floor jack and 2x12 under the oil pan method.

[Mxfrank]

The engine lift gives you more room to work, but otherwise there's no advantage. I leave the opposite side attached, and just lift enough to get the new mount in. You only need to get it to "normal" height, plus a little bit of wiggle room.

[Mike D]

Overkill for the "week end wrench" but it's the "bees knees" for the dedicated mechanic. No worrying about the jack moving, no working around the jack handle and the engine can be pivoted and swung without worrying about slipping off the block.

Getting ready to change out engine mounts on an '85 300SD. Still need to pull the fan shroud, air cleaner, disconnect the linkage, attach chain and put it on jack stands.

[Skid Row Joe]

Originally Posted by jay_bob

Well the official WIS procedure tells you to lift it from above using the lifting lugs on the engine when doing this.

But of course most of us don't have a sky hook in the garage so we use the floor jack and 2x12 under the oil pan method.

DO NOT lift from the bottom of the oil pan. Lift further back on the cross member superstructure immediately fore the transmission.

[ESchwab]

Here is a Wiki paper that might be helpful.

PeachPartsWiki: Motor Mount Replacement

[Mxfrank]

Originally Posted by Skid Row Joe

DO NOT lift from the bottom of the oil pan. Lift further back on the cross member superstructure immediately fore the transmission.

What is a "cross member superstructure"? If you jack from below, you can jack from the pan, the bell housing, or the transmission pan. Which of those are you talking about?