WELL, I guess I should answer this one for sure! I have been trying like crazy to get to every one, but sometimes I can't. If I get to my desktop after 10 hours of work, 1hour on the phone about the new shop, eating supper, showering, giving my two girls a bath, and answering e-mail, I sometimes don't get to all of the questions. I'm sorry for that. Our forum is growing, but so is the number of techs we have, I am not the only one (thank god). The other techs we have are VERY KNOWLEDGEABLE. THANKS FOR ALL OF YOUR WORK GUYS.!!!!!!!!

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

You guys are doing very well indeed.

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David

His:
2003 Dodge Durango SLT
2002 BMW E39 530i Sport
1988 Mercedes 300TE
Hers:
2003 Chevrolet Suburban
1999 E430

heeding the Good advice.I started the car this morning.Moved off and listened very carefully.The sound is more of a knocking sound than a pinging.Again it will not do it if the car is not moveing.Only when you give it a little putz of gas.It does not do this for long.Than for the rest of the day no noise.The car has very low documented Mileage.The engine is spotless inside.There is no air pump on the model.With your help I shall overcome.Thanks Michael

Timing chain? Tensioner?? Maybe not pumping up right away, allowing the chain slap, then once pumped up, tensioning the chain and quieting the slap? Just a guess.

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Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Hi there,
Please tell us more about the knock - does it sound like a "tapping" noise, or is it a heavier sound, like a "klunking" noise? Can you feel it through the seat when it's occuring? Does it sound like it's coming from the engine, or do you think it's coming from the rear of the car, or maybe the transmission or driveshaft area? How warm does the engine get when the knock disappears? Does it only occur under heavy acceleration, or does it also manifest itself under light throttle? It could possibly be coming from a number of places, from a rattling tailpipe to a rod knock or piston slap, or a bad center bearing, or even a bad motor mount, so even though the questions might not seem important to you, they might be very helpful to the people reading your thread so they can zero in on an accurate diagnosis. SO, what I'm trying to say is this: even though it might seem insignificant or even dumb, please try to answer the questions, and lets see if we can be of some real help!

Thanks,
Richard Wooldridge
Mechanic for over 45 yrs
1982 Mercedes 300D/4.3lV6
1977 Jag XJ6L
1977 280Z
1974 Mercedes 280C

If Mike's hunch is right, this is very scary. The V8's are sensitive about their chains and guide rails. It would be really comforting for an experienced MB Tech that has been around long enough to have seen a number of V8's to give it a listen. If it is the chain or a broken rail, you don't want to learn the next failure step.

Best of luck,

Richard.The noise only happens first time I start it in the day.It is deffinatly comeing from the Engine compartment.The engine can not be made to give forth the sound,just by giving it more gas while not moving.When moving,And you pat on a little gas.You get the noise.At first I misdiscribed it.As a pinging sound.It is more of a light knock.no You cannott feel it.In three our four minutes the sound goes away.Let me reinterate No noise when not moving,no matter how you rev the engine.With so many people trying to help me I wish i where more articulate.But noticeing my spelling Its obvious I am somewhat limited in communicative ability.Thanks again.Michael

Although it is possible and maybe even likely that this is a simple problem with a simple fix, I think it would be a good investment to find a trustworthy independent shop and have them take a look at it. Like Larry said, if it is a problem with the timing chain then the next failure step could be a very expensive headache.

Or I suppose somebody on this forum could suggest a fix and your problem could be completely unrelated to the chain. Time will tell, but hopefully not in the form of some serious engine work.

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Ben

The MBs:
1976 300D (W115) - 330K and still going (sort of)
1991 300D 2.5 Turbo - Sold at 221K
1983 280SEL - Sold at 206K
1981 300SD - Sold at 232K

Ben i agree with you.I live in the country,there are not Mercedes dealers anywhere close.Awhile back When I had a strange problem with the car,I had it taken to a recommended service place.They charged me almost Five hundred Dollars to diagnose a bad coil.I am gun shy now.I live in southern Maryland I would love to know the name of an honest tech.around here.Michael

Try searching or posting on the Good MB Shops general discussion forum. I have no idea how many members are from your area, but it is possible that somebody knows of a good MB shop nearby.

__________________
Ben

The MBs:
1976 300D (W115) - 330K and still going (sort of)
1991 300D 2.5 Turbo - Sold at 221K
1983 280SEL - Sold at 206K
1981 300SD - Sold at 232K

Hi Michael,
From your description, it really doesn't sound like the timing chain, although the timing chain is about the only weak link (no pun intended) that particular engine has. I have another question for you. Has the engine ever been overheated? You are describing the kind of noise that piston slap makes - the piston is a little sloppy in the cylinder bore, but after it warms up the skirt expands enough to take up the slack and the noise goes away. This kind of problem can be brought on by overheating, even for a very short period of time. How many miles does the engine actually have? If it's around 100k, you should definetly have the timing chain serviced, regardless of it's apparent condition. Have you changed the brand of oil recently, or gone to a synthetic lube? Get back to the board if you can supply these answers!

Regards, Richard Wooldridge

Dear Richard thanks for attempting help.The miles are 49k.There are service tickets.And i was years enough in the car bussiness That I am sure the miles are right I bought it from a private owner.Who works on Capitol Hill he bought it from a congressman who was the original owner.As far as it having been overheated.I cannott say.I did Change the oil over to Mobil one.As I said I only recently got the car.It did not make the noise when I got it.I did send it to a shop to fix a vacumn leak in the climate control.I usually do my on work.But I could not figure out that problem.This car is a play thing Not my main driver.It may have been making this noise as soon as I got it back from the shop.I did not use it for a week or so.So I can not give a definative on that.Thanks again Michael

Hi again,
Wow! That is a LOW mileage car! No wonder you are concerned with the knock! I have a suggestion for you. It's possible that the Mobil one doesn't have the viscosity the engine is used to. You are in a fairly warm area for most of the year, so I recommend that you change the oil and filter, putting in 20-50W. I'm thinking that probably it didn't knock until the oil was changed to the Mobil One, and the new oil is thin enough so it allowed the noise to surface. This idea won't cost you much, and might take care of the noise. I have been using 20-50W Valvoline in all my vehicles for many years, and one of them has over 350K with no problems! (The 280Z, wouldn't you know it's the Japanese car that has held up!) (I live near Portland, OR, where the climate is moderate all year long, though - I wouldn't recommend 20-50W in a real cold climate in the wintertime.) As you probably know, your engine has a single row timing chain, and they went to a double row with the later engines, after they discovered the single row had wear problems that showed up around 100K miles. It is MUCH cheaper to have the chain and sprockets replaced while the engine is in good shape than it is after the chain/sprocket has slipped, allowing valves and pistons to collide. So you should think about having that job done somewhere around 80K or so....
Regards, Richard Wooldridge

Dear Richard I have pulled the valve cover.The car has a double row chain.I will go back to regular 20 50 castrol to see if that quites it down I very much appericiate you trying to help.Michael