Originally Posted by benzdude42

so i've been bothering this form for almost 2 years about this nasty knock in my 300d that i couldnt track down. Mysterious 1985 Mercedes 300D Engine Knock - YouTube
i know the injectors are nailing pretty bad but it sounded so... odd to be just injectors. i have the engine apart for a rear main replacement and found that the main bearings where pretty beat up pictures here crank shaft bolt.
could this cause that noise? should i dare open up the rod bearings for a look? there is no lose pistons or lose rod bearings that i can see but i will be turning it over a few times by hand when i get the new main bearings in. i honestly do not have a ton of money to sink into a crank grinding if its more that $300 plus new over sized bearings.
everyone i talk to has no idea what would cause this and still have a strong running car after 20k miles.