c250td engine tick question

[E270 Owner]

That's piston slap

It will get worse but can run for thousands of miles like it, there probably a few thousand Vitos sounding like that right now

Why make comment about a 110CDi when the O/p's engine is an OM605?

605 generally are strong engines.

A quick test of it being combustion related is to rev the engine up and let it fall back to idle. If the noise stops on over-run, it's combustion.
Another test is to crack each injector union off, in turn. The one that stops the noise is the duff one.
Yet another method is to use an engine stethoscope to detect mechanical noise.

Because its the noise not the engine type, piston slap is piston slap no matter what diesel engine.

Now the cause of it is another matter.

 

[91dm]

interesting read, that 'funny noise' thread... did u have to buy that timing sprocket new? or did you just find it and found a block of gunk somewhere, like how much of a job was it?

thanks so far you guys, i'm sorry to be bringing this issue up again and i should have searched more at first (bad me).

I cleaned the original sprocket but then decided to buy another just incase.

Does the noise change when the engine is warm?

 

[deian]

The noise doesnt change when its warmer, but there does seem to be a leak around two of the fuel pump outputs, I think oil may have leaked from the rocker cover seal, dripped down towards the fuel line outputs and broken down the o rings where the nuts are? I'll try to post a pic later. Is it a long job to take the manifold off so I can clean the top of the pump? Thanks for the ongoing advice, much apreciated. Finally, the car wasnt like this wehen I bought, it suddenly developed, probably because I drive it harder than the retired guy whom I bought it off.

 

[91dm]

The noise in mine changed when the engine was warm so could be a different cause.

The delivery valve seals are easy enough to change, the seals and washers can be bought from the dealers.

The manifold is easy to remove but you should be able to clean the pump without removing it.

 

[deian]

Based on my previous post, can I eliminate piston slap?

 

[E270 Owner]

Rebuild the bottom end.

Some replace just the piston and sell the car.

 

[Dieselman]

Based on my previous post, can I eliminate piston slap?

Buy a cheap engine stethoscope and have a poke around the engine.

I doubt it is piston slap.

 

[krimat2005]

agree with Dieselman, propably injector leaking. try that cleaner "stuff" together with proper "italian tune up".

 

[Dieselman]

Try the rev and over-run test...costs nothing, will eliminate combustion noises.

 

[91dm]

Suggesting an engine rebuild is getting carry away.

Have you used the tank of diesel yet, any difference?

As dieselman said, rev the engine and record it from outside.

 

[BlackC55]

Piston slap!

This isn't a vauxhall.

 

[deian]

I had a cavalier with piston slap, it was awful, it was the big end bearings.

Something tells me it's not piston slap. The noise is the kind of random diesel clatter not in time with any kind of mechanical movement (if you know what i mean). I suspect another injector or leak is happening too since, when it happens (intermittently) it sounds even more diesel-ish (think an old french diesel when cold). And just to add, it does pink under load.
So I want to (maybe making myself feel better) eliminate the piston slap.

I'm thinking that blocked oil channel in the timing gear that 91dm had.

Could you (91dm), tell me how u go to it? Does it need a lot of disassembly? Removal of the rocker cover exposes the timing gear I think, it is easy to remove the blockage without taking more stuff off?

The noise doesn't really disappear when warm though (does that eliminate piston slap, since metal expand when warm).

I will pop into MB dealer today, buy some seals and washers for the injectors, rocker cover seal, and take it from there.

Anyway, I really appreciate all the help and advice here. This a good forum to be on.

 

[deian]

Ordered a rocker seal cover, doing that job will allow me a good look at whats going on.
Dieselman, you mentioned dribbling injectors, will all be revealed when I take the rocker cover off?

 

[Dieselman]

No it won't.

I'm getting bored of asking for a high rev over-run test. Any chance of doing one before we have any more conjecture.

Sorry to be abrupt, but we are just wasting forum space now.

In addition you won't see anything inside the cam box. The timing gear is behind the vacuum pump.
Flushing the oil would probably fix the timing gear issue...if that is what the problem is.

 

[deian]

Sorry, yes I have done it, I revved her high and let it go and the noise didn't disappear as such. Not recorded on video for sound yet. I'll done one tomorrow, promise.
BTW: Conjecture, that's a good word.

 

[Dieselman]

If the noise was still there as the revs fell then it's mechanical, not combustion at all, so you can forget the timing gear and injectors.

Buy an engine stethoscope.

 

[E270 Owner]

100% piston slap

I have heard this 1000's of times on Mercedes engines.

A piston has caught the bore and is tapping at the top/bottom of its stroke.

Please take it to a engineering company that rebuilds German engines and let a professional listen to it.

Piston slap!

This isn't a vauxhall.

It certainly isn't and at 10x the cost it shouldn't have the faults of a 15 year old designed Vaxuhall engine either.





.

 

[deian]

So this can happen instantly? I bought it and it was fine, then it suddenly happened. I can understand if it was something that happened in the space of say a month. And there have been times, intermittently when it has kind of not been there, for whatever reason. But it has seemed to fail the rev test. Very weird. Anyway, I guess we should close this thread, unless anyone has any final words?
Thanks to all who contributed.

 

[Dieselman]

Buy a cheap engine stethoscope and have a listen.

Now you are trying things and reporting back there is useful info.

 

[deian]

Oky doky. I will try that injector loosening thing u do as well. (do i do this with the engine off, and then start it)? I will buy a stethoscope too.
I should note, that one of the glow plugs hasn't been put in too tight either, the mechanic got scared of cross threading the thread and didn't tighten it too much.
Give me the weekend and I'll report back.