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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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99 Posts
Discussion Starter #1
I have a 1999 E300TD that has a very annoying knock (see video link below).

I only hear that knock up to 1000 RPM. After that, you cannot hear it (until the car's RPMs return to that range.

I have replaced all six injectors, which did nothing to help the knock. Where should I start?

Please watch the youtube video below:

 

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1997 E300D
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508 Posts
Mine used to sound just like that, before I put a cetane improver in the fuel tank. The clatter was reduced to where it sounds almost civilized. Yours seems to have a bit of a lope in it, as does mine. I have assumed it is from the action of the governor, but that is just a guess. I do not hear a knock. Try a double dose of Diesel Klean in the grey bottle. I think you will be amazed. I use it at the recommended dose, and the wife is much happier driving the diesel now because she gets less unwanted attention at stop lights than before.
 

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1999 E300 TD
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2,045 Posts
Although your mileage improved with the new injectors, that did not solve the unique noise---Oh well!!

The sound you hear is NORMAL, under 1000rpm, with all mechanical injector pumps including the MB. You don't hear the noise at higher rpm's because the harmonics of the pump are different at all rpm ranges.

The unique noise that you hear is the injector pump pressure valve and pump plunger opening and closing to deliver fuel to the injectors.

You can quiet the function(even out the individual plungers Db) somewhat by changing all six copper washers and pump plunger springs. Otherwise by a new V6 cdi diesel-----all electronic fuel delivery
 

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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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99 Posts
Discussion Starter #5
Thank you for your replies.

My concern is that the car is MUCH louder than all of the other e300 Turbo Diesels I have heard.

Maybe the video is not capturing the loudness, etc. :(
 

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1997 E300D
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508 Posts
I wonder if it could be a timing thing, with the explosion taking place before top dead center. It seems like that could be noisy. Has anyone messed with anything that could have affected the timing?
 

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1997 E300TD
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39 Posts
get youre car to a shop and get the pump adjusted the timing is of...high milage cam chain can get the timing of with 4-5 degrees mine did the same but after i got the pump adjusted it sounds like a petrol engine now...
 

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E300TD 1997 W210 Running on WVO and a % of dino...
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1,206 Posts
Can you do a video with the oil cap open?
You might be surprise with a louder noise.
Mine sound like yours but the cap open.
If you want to advance the timing its not too difficult but a little tedious.
 

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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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99 Posts
Discussion Starter #10
The car does have 195k on the motor. Do you think it might be time to replace the timing chain and then have the injection pump set for the new chain, etc?
 

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E300TD 1997 W210 Running on WVO and a % of dino...
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1,206 Posts
I don't know.
check the noise when the cap is open and see if its like a tuk tuk in there.
I got that and :
2 MB mecanics listen to it and they just shrugs their shoulders and were surprised.
1 private MB mecanic said it might be a piston slap.
1 other private MB specialist said its perfectly normal.
Dunno who to listen there anymore?
 

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1997 E300D
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508 Posts
I think I would simply have a diesel mechanic with Mercedes experience, adjust the timing to spec. I am not a diesel mechanic, but I would expect that wear would retard the timing, not advance it. Since it is just a guess that your timing is too far advanced, spend as little as possible proving or disproving the hypothesis. Your mileage is not high for a diesel. Mine has 210K on it's original timing chain.
 

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1999 E300TD 176,000 miles/ 1998 E300TD 195,000 miles
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30 Posts
Fuel lines

Sounds normal to me. The cdi engines are the first generation of diesels that are really quiet.
The oil cap is upside down.
LOL Yes I saw that 2. But the first thing I saw was the fuel lines NEED to be changed! The lines should be clear so you can see the fuel in them. I just Changed ALL fuel lines (under the hood) on my 99' E300D and it seems to be a bit smoother / and not as much knock. Oh And fuel filter change too. Maybe just me. My 99' is not as loud as my 89'. I would change the air and fuel filters, all fuel lines, sov O ring, and oil. Everyone asumes your oil is up to the full mark......right? Your car sound fine from here, good luck.:thumbsup:
 

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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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99 Posts
Discussion Starter #14
Is it possible that a bad MAF sensor could cause this?

My check engine light also recently came on and the code was referring to a bad MAF.

Could a faulty MAF cause this type of "knock"?

Thanks for everyone's help with this.
 

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1999 E300 TD
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2,045 Posts
Is it possible that a bad MAF sensor could cause this?

My check engine light also recently came on and the code was referring to a bad MAF.

Could a faulty MAF cause this type of "knock"?

Thanks for everyone's help with this.
Absolutely NOT!!

Get the MAFchanged and you will notice a marked improvement on your mileage.

Before you start messing around with the timing------how about finding out what the timing is FIRST!!!! If it is way out and I seriously doubt that then address the issue.
 

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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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99 Posts
Discussion Starter #16
Ok, thanks.

I still cannot seem to figure out what is causing the "knock"..the car is significantly louder than the other e300 diesels that I have heard.

The car also stutters between 500-1000RPM.

Thanks for everyone's help.
 

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1995 Mercedes S500, 2009 ML320 Bluetec, 2013 ML350 Bluetec, 2005 e320 CDI, 2006 e320 CDI
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99 Posts
Discussion Starter #17
Stealership's Diagnosis

I took the car to the local stealership for a diagnosis of the "knock"

Here is what they found:

- Injection Pump timing needs to be adjusted
- Slow on acceleration & smoking upon acceleration

They quoted me $650.00 to perform the injection pump timing.

What does everyone thing about this diagnosis?

I appreciate everyone's valuable insight.
 

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1997 E300D
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508 Posts
Sounds ridiculously expensive to me. At the normal Mercedes labor rate, that is about 4 to 5 hours of work. I think I would shop around.
 

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E320/E250 Bluetec Ford F350 6.7l
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36,729 Posts
It has to be easier to adjust the timing than 4 hr?
Than if the timing got miss-adjusted by that much, I would worry about timing chain.
What is the mpg at this time?
 

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1997 E320, 1997 S320
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2,946 Posts
first of all that diesel engine sounds normal to me. my dad was complaining his older mb diesel (OM602) had become louder, and last summer when i went home i did a "diesel purge" treatment. engine got a little quieter and seemed more responsive, but could have been all in my head:D. anyways, a can of lubro moly "diesel purge" can be bought at any napa autoparts store for around $5. below is the site i used for instructions and it says what you need. it's a very cheap and easy try, doesn't hurt to try. How to do a Diesel Purge on your Mercedes Diesel | eHow.com
 
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