Alternator from top or bottom?
 

This is for my E300D. New alternator with pulley arrived today. In looking at the job, it seems like dropping the old alternator down and installing the new one from below is the easier way to go. Looks very tight to try it from above - lots of hoses, etc. in the way.

I've got another post I started a couple of weeks ago with the subject of "Alternator Belt." Got lots of input there. Thank you for that. Got a new belt to replace while I'm doing the job.

Just looking for tips on doing the alternator. BTW it's a lot heavier than I expected. It's a rebuilt unit. Came in a Bosch box. Hope it's a good one and does the trick. Wish me luck.

You have to remove the intercooler pipe that’s in the way to get the alternator out.

Or you can do it all up top and remove the thermostat and get the opportunity to throw some new coolant in it! This way is way easier I think.

I did it from below
 

Here's a thread with experiences and instructions and link to another thread with more. The charge air pipe does comes fairly easy and maneuvering the alternator out is not hard, but as with most things, I do anyway, patience and good gloves are required.

https://www.peachparts.com/shopforum/diesel-discussion/213992-w210-om606-turbo-alternator-removal.html?highlight=om606+alternator+removal

I would have taken the rebuilt alternator for a free bench test if they do that in your area. All of the Autoparts chains do that here.

That way you don't go through the labor to install a dead alternator and have all of the troubleshooting grief and have to go through the labor to get it off again.

If the alternator tested OK and you installed, and it is not charging that gives an indication there is something wrong elsewhere.

Diesel911 - thanks for that suggestion. I never would have thought of that, In fact even after you suggested it, I was hesitant. But then I figured that it would be a lot more convenient to take a short drive and get the thing tested rather than install it and find out I got a bad one and have to do it all over again. So I had to go to four places to finally get it tested. Two of them had their machines down. One only tests GM units. Finally O'Reillys tested it and all is good. So now it's on to the job. Today or this weekend.

Best of luck!

Fought with the new alternator job for two days. Finally got it in and everything wrapped up today. Took it out underneath after removing the intercooler pipe as suggested above. Sure made it easy to remove the old alternator and place the new one. Wasn't all that easy to get the pipe reinstalled, but eventually it went in. So now all I've got left is to put the new belt on and hope all is good again.

That was good advice!

I once bought an ACDelco rebuilt Bosch starter for our E320. Had local shop install it. Didn't test it first, only to find it was completely dead. Returned to Rock and then had old starter rebuilt locally. Double labour at shop :(

I always do them from the top, takes me about 10 minutes or less. I have never had to remove anything other than the intake tube off the turbo.