At higher rpms before each shift I get a bunch of random clicking coming from the engine. When it shifts, no clicks... when I decelerate, no clicking. It does not do this when the car is in park and I rev the engine, only while driving. Does occur with bumps in the road, or turning, or braking. If I hold it at that higher rpm, the clicking continues.

When I had the truck I had some 'pinging', or detonation when something was wrong with the timing etc etc. High rpm's= bang bang bang. This made me think something with injector nozzles, timing etc. Did a valve job about 5,000 ago and checked teh timing chain stretch. 6 degrees I believe it was.

I found this thread, but it dropped off.

Engine Clicking

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1981 300D 205,000 mi.

You sure it's the engine?

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

The W124 bible says "New Chain" at five degrees
(of course that's a 602 not a 617 like yours)

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'84 300SD sold
124.128

It definitly sounds like it is coming from the engine location.

From what I have read on here is that the factory service manual recommends the use of a key to bring it back to specs. There seems to be a consensus that the chain on the 617 will outlast the engine. This, of course, will be debated.

I wish that poster from a year ago would come back on and say if he figured it out.

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1981 300D 205,000 mi.

Exhaust leak?

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'81 300TD Wagon 355k (Miss Diesel)
'83 300SD 180k
'84 500SEL 190k (Parting it out)

Sounds like bad fuel, or improper timing. Maybe a bit of both.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Dare I say it's gotten worse the last few weeks. It's hard to tell for sure where it's coming from... maybe the transmission is making noise, and I'm hearing it kind of from the engine bay. It's hard to pinpoint. it's a high pitched click...not a 'ting' or a 'clunk' ....ha ha. And it goes pretty crazy now under acceleration. I've noticed the idle is rougher now, so I'm going to start with the engine. Redo the valves, new injector nozzles, woodruff key.

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1981 300D 205,000 mi.

It will click just a bit in park revving at idle. From what I could tell with my tube it sounds like it is coming from the block? I found that if I go full throttle while driving it does not 'click' at all. but at low/med. throttle while driving at high rpm it makes some major noise.

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1981 300D 205,000 mi.

I had a slightly leaking pre-chamber, sounded a lot like a lifter, but only on acceleration.

A little spotty with dirt/fuel above that injector, spit water back at me when I washed the engine (running), otherwise would not have figured it out.

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Gone to the dark side

- Jeff

Cool, I'll let into that too. It seems like the clicking (more like banging now), bad milage, occasionally blue smoke at startup, rough idle, all kind of started at the same time.

I thought pinging (as gassers call it) was a result of to ofar advanced timing... and my chaing is stretched 6 degrees. Is there something else that causes nailing, or am I not understanding correctly?

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1981 300D 205,000 mi.

6 Degrees ...I would not be running that engine "Hard".

You may be approaching the point where you will not like the result.

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'84 300SD sold
124.128

Really? I havn't read that. I'll start searching some more on that topic. I thought I had read in 'The Timing Chain Thread' that the factory manual says when you can no longer use keys replace the chain, and I think there is an 8 and a 10 after the 6.

Is the infamous air cleaner rattle solved by checking the rubber bushings under the housing, and tightened the four screws that go into them? Or is there another bolt I'm not seeing?

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1981 300D 205,000 mi.

One diagnostic solution is to use a bit of mathematics.

Hold the rpms @ a constant rate (1000 is an easy number)

Hold for one whole minute and the count the clicks that ocurr within that minute.

You have now turned the crankshaft 1000 times in one minute and the clicks should correspond to one moving part.

Compare 'clicks per units of time' to 'rotation of crankshaft over time' to get a ratio of clicks per rotation of crankshaft.

Determine what moves in this relation to every turn of the crankshaft

If this proves to be futile, you have at least determined that the clicks are not consistent with the rotation of the engine and may be just a peripheral item.

I read a thread once where this was a timing chain about to fail. Look in the DIY articles section.

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How much noise can a missing shifter bushing make? The reason I ask is that I read a thread where a guy was missing a 50 cent shifter bushing (I have no idea where that is) and it made a random banging sound at load. It also make a clunk sound when shifting into gear. Which mine does. It's a different sound when I shift into gear though.

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1981 300D 205,000 mi.

When the shifter bushings go bad on my car they rattle pretty good just off idle. Sounds like its coming from just under the shifter.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200