It's a 99 model E300. Used to be my mothers car, and I'm going to be buying it back.

It knocks when it's cold, but once it's warm it quiets down and sounds like a healthy 606. Our friend who has the car now replaced all 6 injectors on the car when 1 injector went bad, but oddly enough it still knocks until warm. The whole engine has been taken apart as well and the bottom end is not the problem.

It has to be fuel related, but I can't think of anything else. Please feel free to chime in with ideas, kind of at a loss.

Jake

Bad glow plug? Can you isolate the cylinder that's knocking? I had that problem and I had to re-torque the delivery valve holder.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

I was thinking a glow plug as well maybe possibly. But they were replaced 4 years ago when I had the car and it's only had about 10k miles on it within that period of time.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Can you isolate the cylinder like Kartek suggested? Interesting about the engine being torn apart. Do you mean it was really torn down and rebuilt? Why did it need that? Could it be a case of the new production nozzles not being up to snuff? If I ever get my hands on a good set of original injectors I'm going to hang on to them for testing purposes. If you can isolate it maybe swap the injector with another one.

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What Would Rudolph Do?
1975 300D, 1975 240D, 1985 300SD, 1997 300D, 2005 E320 , 2006 Toyota Prius

No the engine was taken apart. He was concerned it was something on the bottom end. Nothing was rebuilt or changed while it was apart.

I will take a look into isolating the cylinder, I have a feeling it's the cylinder that had the bad injector. Could the nozzles even still have something wrong? These were brand new injectors ordered from MB.

Car only has 160K miles on it.

__________________
Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Unusual to have problems on a 606 with so few miles.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 142k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

What I have done in the past diagnosing diesels is with it running, crack the line loose at the injection pump to make the cylinders go dead one at a time, see which one makes the knock quit. Wear heavy gloves, use a long wrench, face shield, and keep back. It will make a mess of course but loosen the line as much as you can with a swing of the wrench, it will take its ability to develop pressure away with the line nut loose enough.

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87' 300D, Currently undergoing an OM606 swap/build! SUPERTURBO!!!
03' 2500HD Dmax + goodies!
82' 300SD, parting out!
93' 300TE 4matic, parting out!
83' 240D Project Cheap Drive
89' 300E, parting out!
74' Datsun 510 wagon
88' RX7 10thAE, 13B track car build soon

Skippy~ As for perception: Drive what you like and can afford. Those who don't like it can supply vacuum to one of your components. LOL

If you need parts, I have some!

I would still go with checking the glow plugs prior to doing anything else. Easy to do with a multi-tester and doesn't cost a cent. If it is the glow plugs, you will be spinning your wheels trying anything else to solve the problem.

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96 E300d

Glow plugs are easy to check by unplugging the GP relay and checking resistance on each of the 6 circuits.

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CENSORED due to not family friendly words

Tick or a knock? Top of engine or bottom end? Consider a collapsed hydraulic compensator (aka lifter) as a possible cause as well.

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Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~392k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 380k miles
'73 Balboa 20 "Sanctification"
Charleston SC

Not like a lifter when they go bad and do that ticking.. It's more of a knock. Like a fuel knock.

It's nothing major. Doesn't affect the performance, or MPG, or starting ability of the car. It's just annoying and needs to be fixed is all. After replacing the injectors, the fuel economy went back to a regular 35 on the long highway trips that it used to get.

I think this is the first thing I'm going to do is check the glow plugs..

__________________
Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k