Ok, I think this will end the vibration problem.

I posted a while back, and posted there too, so it's a complete thread.

I thought maybe it was the injectors, I did a Moly diesel purge, etc. VERY annoying vibration at idle.

I had a general mechanic and a parts place look at my motor mounts, and they said they were fine.

Someone gave me the tip of putting a jack with a block of wood on top of it, put it under the engine, and lifting the engine slightly to see if the vibration goes away, which it did.

That means it's the motor mounts.

Mind you, the motor mounts have TWICE the thickness that someone else posted was the minimum. But it turns out, one gets pulled, the other gets squashed, depending on which way the drive shaft turns. Therefore, the one that gets pulled ... LOOKS fine, but it's not fine.

Next question, how hard is it to change out motor mounts? Is this a DIY job for a less-than-great mechanic?

We should have some threads on changing motor mounts:
DIY Repair Links
http://www.peachparts.com/shopforum/diy-links-parts-category/

http://www.peachparts.com/Wikka/DoItYourSelf

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84 300D, 82 Volvo 244Gl Diesel

I took a look at those links, and didn't find anything (I'm sure it's in there if I read each and every single post, but that'd take 5 days). I also looked at the DIY, nothing there, and I checked DieselGiant and youtube, but nothing on Mercedes motor mounts.

Anyone change out motor mounts? Is it a DIY project?

1991 300d

Sure, lots of folks here have changed out their motors mounts - I think it is a fairly straight forward DIY job if you have the safety equipment and tools. If you have questions during the process just ask. I agree with Diesel911 that you will probably find a lot of info through a search. One thing that makes searching here much better is using the advanced search options. Open up the little search window, then click on "Advanced" in that window. That will take you to a new search page. On the page you can customize your search. I do a lot of "Title Only" searches - it is much better than the default search that looks for any post that contains your search words. Searching by titles helps you find threads that are much more relevant to your problem.

If you want a quick step by step, I can give you one, but I am sure it is already here.

EDIT: Why not use Parrot of Doom's write up on the procedure?
http://www.peachparts.com/Wikka/OM606MotorMounts
I believe the motor mounts are fairly similar, so the procedure would be too - perhaps not identical, but it would probably give you all you need to get the job done.

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'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
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"Back off, man. I’m a scientist” ~ Peter Venkman

Well, he was pointing you towards the DIY pages and a quick scan of titles will tell you all you need to know - more like 5 minutes than 5 days. That is where the 606 motor mount replacement DYI (by Parrot of Doom) is located. I think it will work for you.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman