Author Topic: OM617 Engine Knock  (Read 10285 times)

Casey

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Re: OM617 Engine Knock
« Reply #15 on: 01 September 2011, 04:32 PM »
Stuff happens, it's how we learn sometimes  :o 

Did you pop check them and all that stuff? Didn't you get one of those testers?

I'd be interested in hearing about that!

Yes I did, along with a set of various thickness shim washers, and an electronic caliper.  Works great but I can't see holding onto this once I'm done with it, so it's for sale if you're interested.  It would be really handy if you did this sort of thing all the time or intend to sell it after you're done.  Two of the injectors from the CD could use some minor adjustment, but it's with 100psi which is acceptable per MB standards...

Janse

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Re: OM617 Engine Knock
« Reply #16 on: 10 September 2011, 12:00 PM »
Have you checked the vacuum pump? It often makes a knocking sound before it brakes. If that brakes you can be in big trouble so get it checked. If it brakes the chain can brake as well and ruin the whole engine.

Casey

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Re: OM617 Engine Knock
« Reply #17 on: 10 September 2011, 02:16 PM »
Have you checked the vacuum pump? It often makes a knocking sound before it brakes. If that brakes you can be in big trouble so get it checked. If it brakes the chain can brake as well and ruin the whole engine.

How can I check it?  The knocking is continuous and aligned with the RPM's of the engine, but I can drive around just fine.  I've been driving it short distances on the weekend only.

Janse

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Re: OM617 Engine Knock
« Reply #18 on: 11 September 2011, 05:26 AM »
I will check with my brother in law who loves these engines and is a mercedes mechanic. I dont know squat myself. I might be mistaken about the whole thing, as a malfunctioning vacuum pump makes more of a ticking sound than a knocking sound, but you might say that that is a poteito potato thingy... :P You will be able to drive quite some distance before the vacuum pump brakes, but I would leave the car still until You find out whats wrong.

Casey

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Re: OM617 Engine Knock
« Reply #19 on: 11 September 2011, 05:37 AM »
By the way I was driving it a lot more and the oil had gotten quite low prior to this happening, so that could be related.  This car leaks oil like it has an arterial wound.

Janse

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Re: OM617 Engine Knock
« Reply #20 on: 11 September 2011, 11:42 AM »
Talked to my brother in law, he said that it might also be the timing chain. How many kilometers has the engine run? I prefer changing them after 300 000 km, but I have heard them breaking after much shorter distances. I think it is worth taking the car to a garage to sort out all the issues. Much better to change a few parts now instead of having to scrap the car is everything goes to hell...

Casey

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Re: OM617 Engine Knock
« Reply #21 on: 21 September 2011, 12:43 AM »
Tonight I replaced the valve seals and adjusted the valves to MB specs.  Visually verified all glow plugs work with injectors removed.  Timing chain seems good - no play.  After it was all done, the knocking persists. :(

I do have a new timing chain and tensioner that I bought for my 300SD which I could use, but I think it's beyond my ability to replace.

arman

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Re: OM617 Engine Knock
« Reply #22 on: 21 September 2011, 01:54 AM »
Hi Casey,

Earlier I did some research on an OM616 diesel MB engine which is a 4 cylinder diesel variant of the OM617. A friend of mine has a MB van 207D with this engine, that had got stuck.
I discovered something called 'piston slap' which is unfortunately not a good thing to have. I don't know much about it, other than that it makes the engine noisy. I know also that both OM616 and OM617 are one of the most reliable engines ever made and that this is not a common problem.

Some links:
http://www.youtube.com/watch?v=u4cCfipWgI8&feature=player_embedded
http://www.youtube.com/watch?v=tOhLBkBR1k0&feature=related
http://www.pistonslap.com/

I sincerely hope that this is not your problem.

Good luck!
1974 W116 450 SEL 340.000km
Black exterior (040), olive green velours interior (966)
http://gallery.w116.org/v/show_room/Armans450sel/

Casey

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Re: OM617 Engine Knock
« Reply #23 on: 21 September 2011, 02:07 AM »
Hi Casey,

Earlier I did some research on an OM616 diesel MB engine which is a 4 cylinder diesel variant of the OM617. A friend of mine has a MB van 207D with this engine, that had got stuck.
I discovered something called 'piston slap' which is unfortunately not a good thing to have. I don't know much about it, other than that it makes the engine noisy. I know also that both OM616 and OM617 are one of the most reliable engines ever made and that this is not a common problem.

Some links:
http://www.youtube.com/watch?v=u4cCfipWgI8&feature=player_embedded
http://www.youtube.com/watch?v=tOhLBkBR1k0&feature=related
http://www.pistonslap.com/

I sincerely hope that this is not your problem.

Good luck!

This is exactly my problem, I think.  It sounds identical.  Is the car safe to drive as-is?  I'll replace the engine if need be.

On my local Craigslist, there's a 1985 turbo OM617 with 240k miles for $450, and a 1982 300SD with 150k miles being parted out because a tree fell on it - the engine is available.

The car was neglected like hell in by previous owners.  Amongst (many) other issues, the engine bay was solid black (thick buildup) when I got it, and there was a lot of blow by and oil pooled up in the air filter housing.
« Last Edit: 21 September 2011, 02:10 AM by Raptelan »