Timing Chain rattle?
 

2005 Turbo diesel with 172,000 k's driving normally in low revs the engine is very smooth and quiet, especially for a diesel. When I accelerate hard and from about 2500rpm it makes a rattle sound very much like a lose timing chain hitting the cover. Anyone with a diesel tell me if your car is quiet at higher rpm, as diesels are normally noisier at idle, or if noisy like mine? Also free revving it in neutral it doesn't seem to make the noise as I would expect it to. The car doesn't blow any white smoke and it does not sound like detonation (pinging).

My 2005 3.0d with 200,000km doesn't do that. In fact, having just changed the oil (Castrol Edge 5W-30) it's so smooth and quiet at all RPM I can't quiet believe it. I changed the engine breather/oil seperator too, about a week before the oil change, so that may have something to do with it too.

There's a few items that could rattle - the actuator rod on the turbo variable gate is one that comes to mind but I'm not sure it would be a clattery as a cam chain hitting the cover. The v-belt tensioners can make a racket when badly worn too.

And then there's the vacuum pump on the front of the exhaust cam.

Injector.

Do diesel injectors make a noise if faulty? I don't know much about diesels. They are new to me.

Do diesel's have Timing Chain Tensioner?
On my 3.0i (gas) it's a $4 spring that pushes a piston against the chain guide rail. Have read they can quiet a "chattering" noise.

going to do mine this weekend!

Mine did, only symptoms were rattling under load, new injector sorted the issue.

That was on a BMW M47, so very similar engine to yours.

If the injector on one cylinder isn't working, then that cylinder is under very different dynamic forces compared to the others when they burn fuel. A simple way to visualise this is to say that the iffy cylinder (piston) is being pushed rather than pushing. This will likely be the "clatter" noise - an unloaded (of differently loaded) piston/rod assembly.

But I'm no expert either - just chucking that out there as a theory. But it might pay to look closely at the injectors. :confused:

Further info it seems to do it on part throttle when transitioning load and it does actually do it in neutral, I checked it again yesterday. I am thinking it is most likely the tensioner or possibly the variable valve timing gear, can they make a noise if worn? Will check it out with a stethoscope, in neutral.

Swirl flaps removed already?

Pretty sure no E53 was ever fitted with swirl flaps.

Yes, I know they are listed on the parts fiche - but the parts fiche is a part copy from other M57 engine cars and are not 100% accurate.

If anyone has swirl flaps on an E53 or knows anyone that has them, they would be a world first.... :confused: