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R129 SL500 (129.067 119.982 722.620)
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18 Posts
Discussion Starter #1
Got my MY1998 SL500 a year ago, it was road tested by local MB dealer and no issue was noted.

However, I note strong vibration when the engine is revving high (4000rpm+). Put the car at “P” and apply gas slowly, the engine run smooth until reaching 4000rpm, when it start violent vibration. The vibration is so strong that you can hear the sound of tyres rubbing against the cement ground. Open the hook and observe the vibration, it is in the direction left / right +- 5cm, frequency like 0.5 to 1Hz.

Have all three engine supports replaced with genuine MB parts in a local workshop, the magnitude of the vibration remains the same but now it happens a bit above 4000rpm, like 4100rpm. My indy said it is normal, however I think he just don’t bother messing with it. Yes in real driving such vibration above 4000rpm during hard acceleration would be masked by road vibration, but it just bugs me.

Any idea? Perhaps the tightening torque applied to the new engine support was not correct? Or anything to do with spark plugs or MAF? Sorry if it is a novice question. I will try to put up a video to illustrate the problem later. Thanks in advance!
 

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Greek God of the R129
SL500-500SEL-190E
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8,391 Posts
I think that you aren't suppose to rev the engine with out a load.
So the pump module has an rpm limit, is cycling the timing on &off.

Regards,
aam.
 

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R129 SL500 (129.067 119.982 722.620)
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18 Posts
Discussion Starter #4
Thanks for all your reply. Given the age of the car I was hoping any vibration to be improved after exchanging the engine mounts, it now turns out I am worrying too much.

This is a very informative forum with all you guys!
 

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Moderator
SL55, 300SE, GL450, Daytona 955i
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10,293 Posts
how is your flex disk doing? particularly the front one...
 

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Moderator
SL55, 300SE, GL450, Daytona 955i
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10,293 Posts
my bad, desregard the above... since the problem is happening while the car is stationary...

make sure you dont have a misfire somewhere, the 4000rpm point is when the valve timeing changes on the intake side...
 
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