After owning 7 Benz diesels from 1965-1980 models and never replacing a chain except when I did the head on a 77 240, I just did the chain yesterday on the 190D 2.2 I acquired last spring. I probably should have replaced it on the 78 300D I sold this summer, which was loping at hot idle with around 350K on it, but my wife's 80 240 4spd, which I bought at 242K 7 years ago and have put a clutch in, goes click whirr at around 340K and doesn't need it as near as I can tell, although it does use some oil now. The 190D auto with 290K on it I put one of our daughters in when she wrecked her 240 on the ice last winter probably needs it, but doesn't slap.
I am so glad I found this place, because I didn't know jack about these 2.2 diesels when I bought this 85 5spd for transportation, and thought I was listening to valve clatter until I figured our they didn't adjust like the older ones, which I have had some amazing results with just by setting the valves when I bought them. When it dawned it was minor chain slap when hot, I figured this model engine was junk by comparison, because the car only had 153K and was really clean.
So, FWIW, after I read everything I could find here on rolling in chains, I said screw this tearing the front end off the car. I couldn't find a clip link for installation so I just bought a second master link. The chain was $80 and the tensioner was $42. Obviously I couldn't see the lower rail, but the upper was in super shape, with no signs of wear or cracking, and the tensioner shoe was not even visibly scored. I don't have a means to measure chain play, but the thing was slapping, and the tensioner was definitely weak compared to the new one.
Just in case it helps someone, or the real techs need a laugh, here is how it went:
I put vise grips lightly on both sides of the cam gear wheel holding the chain, covered everything exposed with rags, and put my half inch ratchet on the crank pulley. I took my Dremel and ground off the chain swages right into the link, separated the link face by lightly tapping a chisel between the link and the chain, then used a punch, (again lightly) to get the link apart. I hooked the new chain on, peening the master link with ball peen hammer and a small piece of railway track I keep for such tasks held behind it. For ease of installation I left out the center link, used the master link, but slipped a used face link over that and peened it so I wouldn't have to press on the new face link first. I fed the new chain from the box lined up with the gear over the top from the passenger side, and the old chain out the same side under that, moving the crank very slowly in small increments so I could move the two vise grips for insurance alternately, cranking slowly also to make sure the thing didn't back up on me from compression, because I considered it a waste of time to get to the glow plugs or remove the injectors. I figure I got about an eight of a turn each time before moving a grip, but it maintained tension, and neither chain ever left the gear. It took about half an hour to roll it in this way, then I installed the new master link. Because I don't have access to the press tool, I just took a C clamp big enough to cover the link, made sure I had the face link positioned, and cranked it on to flush clearance, then took a smaller clamp above and below the link tines alternately until I had it tight, (being careful not to bend it) then peened it with a hammer, more carefully this time.
Next I blocked the tensioner shoe with a long screwdriver and replaced the tensioner. The thing runs quieter, has a more consistent power curve, and I had to set the idle down.
One question though. I found a vacuum line that had busted off the emissions relay on the p side of the engine some time past and re-attached that. Now the engine does not shut off cleanly. Suggestions?
Trace