Got a clacking in the ol' slug (1983 240D)

I've done a diesel purge (twice), replaced the injector nozzle from where the sound seems to be coming from 4th cylinder at the oil cover), adjusted the valves (lifters).

I even just replaced the front left wheel bearings, in case they were clacking... but no, it wasn't them.. (they needed replacing anyway)

So what is the clacking noise in the movie file at www.pauldrayton.com/uploadfiles/clacking.mpg ? (It's a 13 mb video file. A small audio only file is at www.pauldrayton.com/uploadfiles/clacking.wmv for the bandwidth challenged). The sound gets worse when you ride around for a while.

When I had the oil cover off while doing the valves, I noticed the bar that goes across the top, above the camshaft, has some play in it at the far end. But nothing that could clack like it does. I didn't know how tight the chain at the front should be (is that the timing chain?), so I couldn't really check it. The sound doesn't seem to be coming from the front though. I've listened with a piece of wood all around the engine. The only place I have heard it as on the oil cover at cyl 4.

Could this be the famous nailing? I didn't adjust the bozio nozzle I bought - I just stuck it in. I don't have shims to adjust them anyway - still waiting for the stealership to get them from Deutcshland uber alles. If this is a injector issue, then fine, I'll get them adjusted properly.

But it sounds like something moving and perhaps even slapping. Heck, you listen to it and tell me. If a picture is worth a thousand words, then a sound is probably worth about 435 words, so I'll stop typing now.

Some advice would be great. This is my work car and I want it working!

Thanks

It has a nice diesel sound to it. Except for that clacking sound. Have you tested compression?

You can get a compression tester at www.harborfreight.com.

danny

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1984 300SD Turbo Diesel 150,000 miles

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FWIW, it does not sound like injector nailing to me, it sounds mechanical. I can't think of anything obvious near the back of the engine.

That's definately a wierd noise. It sounds hollow and metallic like something hitting the inside of an big empty coffee can. I don't know if it's mechanical or a byproduct of the combustion process. Have you lifted the hard injector lines one at a time to try to isolate the position of the noise?

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1981 240d
Newport,RI

Don't listent to me, but I think it's just the normal vibration of the engine makes something clack in the engine bay while the whole block moves a little.

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'81 M-B 240D 4-speed 132Kmi
'98 BMW 528i 5-speed/sport 125Kmi
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'04 Suz SV650 track dog
'89 Yam FZR250R

Just to rule it out, check the air filter housing to see if it is knocking in its mounts. Mine resonates a loud clack when it is loose. Good luck!

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'82 240D Euro 68K and growing

Just to rule it out, check the air filter housing to see if it is knocking in its mounts. Mine resonates a loud clack when it is loose. Good luck!

I was thinking the same thing. Mine had a noise similar to that when I 1st got it. It turned out the air filter bracket had broken.

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84 300D 251K
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06 Ford Escape 172K
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did you say that you had had the valve cover off recently? possibly you left something in there?

or a big nut in the air cleaner.

sounds like something being thrown around the inside of the valve cover.

karl

Exactly what I thought it sounded like.....kindof a "whush whush whush, whap, whush whush whush, wap" sound inside the valve cover...when he put the camera closer to the cover it sounded louder....I bet its something in there......

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There I was thinking no-one cared about me, boo hoo, poor me, becuase I hadn't got any emails saying anyone had replied to my post, when I realized I hadn't subscribed to it.,

So I came back here and there are all the answers. Thanks.

I have used a piece of wood (works better than a tube for me) and haven't really been able to tie down where it is coming from. I think it is mechanical - and inside the valve cover.

I have had the valve cover off - I thought the noise might be the valves being loose. So the noise was there before I took the cover off. An experience mercedes mechanic friend of mine just listened to it and said don't run it anymore until you find what that noise is and remove it! He also thinks it is something loose in the valve cover.

I have checked the air filter. It is not the culprit. I think I need to do some snooping. Maybe something got in the air filter and is stuck in the intake some where? I don't know. First I'll take off the valve cover and check I didn't leave a spanner or something in there..... wouldn't that be unfunny! No worse than a surgeon leaving the scalpel in someone's stomach I guess...

I'll let you know when the mystery is solved.... then we can all go - ah yes......hmmmmm.. woulda never guessed that!

pulling bits out, especially from aluminum manifolds can be done with a piece of tubing with a magnet glued in the far end. use a piece of clothes hanger inside to steer it to each intake valve. that's a 240 right? no turbo to remove at least.

karl

if i will make a guess just to give you an idea, i'm not sure about this but try to take the valve cover off and check for the metal plate shroud that is riveted inside it (on the upper side where the breather vent is). there might be some loose rivets which makes the funny clacking noise when the engine vibrates. and since the valve cover is out, try to re-check your valve lashes and also check for timing chain tension. good luck!

I took the valve cover off again last night (getting good at it - took about 6.5 minutes...) and had a look around. No spanners left in the valve area, no loose bits.

After a bit of searching I did see that the one hole where the bolt goes through to bolt the cover on, had a piece missing. Looks like a metal shark took a bite out of it.

I am guessing the missing piece is the problem.

BUt I haven't been able to find it. After looking for a while, I used a magnet to poke around and see if there was anything loose that attached to it. I even pocked it down the air intake to see if I could pick anything up. I considered taking the intake off, for a better view, but didn't know the issues involved there.

Also poked the magnet down the slit at the back, near cyl 4 - I guess this is the oil drain? Anyway, nothing seems to be loose down there.

800Chedeng - how do I check the valve lashes and timing belt tension?

I thought about draining the oil and seeing if something fell out with it, and if not maybe taking the lower oil pan off. Not sure if something could make it all the way from the oil pan to the valves. Wouldn't it get caught in the oil filter? Maybe a copper washer from the last oil filter change dropped in there somewhere.....

Any ideas? Does draining the oil and taking the oil pan off sound like a good idea? Any better ideas?

Why don't you pull the valve cover again and try to tighten this down then see if it goes away?

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So I pulled the valve cover (again) and snooped around. Turns out the spring on the rocker arm assembly is on the wrong way (the retainer clip/spring thingy).

So I took the rocker assembly off and also found that the one rocker is uneven - it is worn at an angle such that the side of the camshaft lobe to the front of the engine is at about .016" clearance, and the part of the lobe near the back of the engine is at about 0". So I moved the rocker arm to see if it was the rocker or the lobe that was worn. Luckily it seems to be the rocker - becuase when I moved it to another valve, it was uneven on that valve too.

Also, the character of the clack has changed. It is more of a sliding sound now, without really clacking. So I think I am on the right track.

Is it reasonable to assume that a worn rocker arm could make that kind of noise?

I guess the real question is why did it wear? It could have been becuase some dork put the spring back on the wrong way, which allows the rocker arm about 1/8" of movement back and forth - that makes it go about 1/8 off the lobe, so I guess it is reasonable to think that it wore unevenly. Actually, that makes sense.

So whatcha think? New rocker arm will fix it?

I have some pictures if needed.

MBeige - it doesn't look like the oil bar (I found out that's what it is called) can be tightened down - the clips holding it are at max tightness, but actually, I am not sure, so I'll check. Thanks.