tappy/clicking ml420 cdi normal?

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Pittnathan

Active Member
Joined
Apr 17, 2013
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67
Car
CLK55 AMG
Hi. I've just part exchanged my 2004 clk55 for the above. It was kind of a spur if the moment thing that I'm not sure if I'm regretting. I read loads of good reviews on ml420's and went to look at one and ended up driving it home.

Is it normal to have a slight tapping noise coming from the engine as the revs climb? Friends say that it's probably normal, but I read the 420 is a really refinedand quiet engine.

Also, is it normal for the 7g gearbox to not be silky smooth. My clk was smoother.

Please help. Have I bought a lemon?!
 
That 7 speed box is clunky and not a great in my opinion. Not sure what noise your engine is making but I'd take it to a specialist (not the dealer) to get it checked
 
From cold they are (like most diesels) a bit tappy but once warmed up you shouldn't really hear it, the engine should sound sweet under load.
 
It does sound good under heavy acceleration. The noise is weird. Almost like a relay clicking or something. It rises with the revs.

I think I'd better ring that specialist!
 
Tappy on throttle or off throttle or both ?
 
Hi, I have the Ml 320 CDI and also have the ticking you describe rises with revs and can hear it at idle warm or cold. I was concerned about it also and took it to MB who advised they are quite 'clicky' like that and said its nothing to worry about. My injectors are all fine and I have no other symptoms, its been like that since I bought it and its never got any worse or better.. tick tick tick tick tick!! ha ha

Gearboxes are good on these provided they have been serviced well. Mine is a little jery sometimes from 2nd to 1st coming to a stop. This was rectified on the later models with a software update that let the car run in second till it comes to a stop I beleive, nothing to worry about but they arent as 'refined' as some of the other Mercs although I do find them lovely to drive.
 
Can i get this software update on my 2006 ml?

Is the clicking really something we have to live with?! It drives me mad!
 
I cant hear mine in the cabin only if I am outside the vehicle, but not inside and I think its a characteristic! lol Benz told me its nothing to worry about and not much they can do...

Gearbox software isnt that simple, there is a re-designed valve body that you have to have before they can update the software and redo all the adaption settings its a bit of a lenghty and expensive process I think.. and can only be done by main dealer.

A gearbox service and resetting the ECU adaptive and throttle settings have made a big difference on mine and the jerk is now very intermittent and normally only when I am coasting to a stop. Here is a link on how to do it....

ECU ADAPTIVE transmission & throttle settings reset - Mercedes-Benz Forum
 
I have a tappy noise on my SLK, it's been there from new, it's only done 3000 miles, it rises with revs but can hardly hear it in the cabin, it's been back to MB twice, they say could find nothing wrong and is nothing to worry about, but couldn't tell me what it is... they say it's not even run in yet etc etc... sounds to me like being fobbed off?

Tried to record it, link below

https://www.youtube.com/watch?v=HmKUp8E5G-w&feature=youtu.be
 
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