That was my conclusion too Tim.

Now with that said, and I'm going to put it out there for anyone else that ever has to pull cams from the M276/278, go ahead and replace all of the cam roller/followers while it is opened up. Easy to do with the cams out.

The cam was not damaged at the bearing surfaces (indicating no loss of oil) it was damaged on the lobes. That was either caused by the timing adjuster being worn out jacking the cam around or the roller/follower going bad. I did find indications on a couple of the roller/followers where there was no cam lobe damage.

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Jim

Hey, read the whole thread. 253k all those issues and still tanking along, amazing. Gives me hope. I have a 13GLK with 136k, and even after new adjusters and tensioners (with check valves already behind them) I've still got the rattle at startup, from chain stretch I surmise. However idle at startup is much improved with the new adjusters.

Did you really have to pull the heads to swap chains? And did you ever find a video or instructions for the entire procedure? I saw a video on YouTube with the front of the motor, covers taken off all the way down to the crankshaft. Made it look like it was possible without taking the heads off.

She still going good? How many miles did you go with the rattle? I know the slap will eventually screw the adjusters. It's a shame there's not a ratcheting tensioner in there to save from this much work.

Heads have to come off. At 274k miles now. Did a 3000 mile round trip ride to El Paso in May. Still runs good and averages 24 mpg.

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Jim