When I cracked the nut to the injector 4, the noise stays there.

There is still a thwack/crack sound when using a 'stethoscope' on the injector line itself, that is only apparent on 4. What does that mean? If the injector pressure is set wrong, would it thwack like that becuase it is early or late in firing?

diget69 - the slug starts 1st time everytime in the mornings. Never had a problem starting, so I don't think compression either.

If you cracked the injector and the noise remains, it's not injector or combustion related because the cylider is not getting any fuel.

Back to square 1.

I could not get the video to work.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

this is DEFINATELY the noise so no need to go any further. notice in the video upper right side of the screen, small green fellow with a hammer? put out a mouse trap baited with hemlock. noise will disappear.
:fork_off:

Brian, itcould still be something loose in the chamber though, couldn't it?

Dieselgiant - sounds like you don't have the mpg codec on your computer, so you can't play the video. There is a slightly bigger, but more generic video at
http://www.pauldrayton.com/uploadfiles/MVI_3619.avi
also, there is a sound only file at
http://www.pauldrayton.com/uploadfiles/clacking.wmv

BTW, I happened to be reading another post about hydraulic lifters and the guys were saying that synthetic oil can help. Also they said that Rotella synthetic sucks. I happened to just put that oil in my car about 500 miles ago. I wonder if it loosened something?

thanks.

Your linkage looks like it's moving/vibrating quite a bit. Try some ATF or bearing grease in the ball joints.

anyway, after listening to the video again with my surround sound turned up, it really sounds like something loose in the exaust pipe banging around... it also sounds like it is NOT coming from the valve cover. have you ... I know this is going to be messy and dangerous, but run the engine with the VC removed? this would eliminate for sure anything in the valve area.
have you checked the exaust pipe for something rattling? it could be as simple as a rock stuck on the collector pipe...
ok if that turns out negative, do a compression check on every cylinder... it could be a broken rod banging around, but it does not sound that loud.

I hope you mean ring...

No that is NOT a rod noise. I have heard that noise before but I dont know what it is. I have heard it in Nissan Altimas and I believe that it was lifter related, but I cant remember exactly what caused it.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

I am starting to think it is lifter too. But what about the lifter? Do I have to take the cam off to really tell if there's a problem?

I had the VC off my wife's 124 and could tell the hydraulic lifter was bad becuase I could push it down with a finger. But how to tell with the spring lifters on the 616?

I'll check the exhaust stuff too, thanks for the tip.

Wouldn't a bent valve cause a similar noise?

__________________
1981 240d
Newport,RI

punky, I don't know - but I hope not, because it is hard to remove a valve isn't it?

I took the oil filter and intake manifold off - there is nothing I could find loose in the intake. The noise is louder with the manifold off.

My next step is to move the injector and see if the noise moves with it.

Absolutely. But, it's not injector.......or fuel........related.

after a LOT of messing around (taking the exhaust manifold off. etc) I tightened down the exhaust valve on 4 to intake specs, and it was a lot quieter. The noise is still there, but it doesn't get clacking loud at all, just a kind of sound like a too open valve gap.

So I don't know what that means, but at least there has been change.

I did the valves again, and did them better this time and the engine sounds really good. No tapping or anything, except for the noise above, which is intermittent and stops at higher revs.

I am still thinking of swapping injector 4 and 1 to see if the thwack I hear on the injector line moves with it or not. I am thinking maybe a badly set nozzle would fire early and cause stress on the cylinder and make an iffy valve noisy?
Whatcha think?

Anyway, still haven't really found what is making the noise, but I'm pretending it will fix itself....