New to me OM602 hot idle

[JHZR2]

Please have a look/listen:

https://youtu.be/0Ry6NJr36ss

This was after 70 miles on the interstate. Operation and idle of engine are smooth as glass. Never felt a smoother 5 cyl diesel at hot idle. 617s always have a funky bit of rock to them, and my 603 engines are smooth like this and quieter but they’re 6 cyl.

I think something is loud. I think it’s the injectors. I’ll definitely be looking to get these popped and balanced in the future. But the engine runs with so much power, so smooth, it’s great. I’ve driven lots of w123 300d cars, and you can see my stable. This w124 2.5 is just so smooth and effortless.

But aren’t the injectors loud?!?

[dieselbenz1]

These engines benefit from an Italian tuneup
After that I'd do a Purge. Sounds good to me but my hearing isn't the greatest.

[JHZR2]

It’s really smooth, no motion of the engine at all, very nice. It just sounds a bit I don’t know…. Harsher or louder of a sound at idle and when overrunning the engine (lack of better terms - when coasting to a stop in gear from a higher speed and rpm).

[JHZR2]

Here is a cold idle seconds after start (it fires first cylinder every time I think). Not cold soaked like overnight, but freezing temperature, sat for probably 4 hours.

It’s a variety of noises that I’d appreciate insight into:

https://youtu.be/Z7cUBy0Wono

[Bengoshi2000]

My '91 was noisy when I got it... injector nailing for the most part. I ran a couple tanks of B99 biodiesel through it (and changed the fuel filters a couple times) and it piped down considerably. Still a wee bit noisy... turns out that was the accessory belt tensioner.



You also need to blow the cobwebs out of it every now and again (the aforementioned Italian Tune Up).


YMMV