Hi Bob, Thanks for getting back to me so quickly.

Mark's original description that started this thread is exactly what I am experiencing -

"The car seems to amplify all road defects rather than absorb them. I describeit as setting up a cyclic, harmonic vibration in the body"
"The vibration occurs above 20mph and continues on at any speed"
"On perfectly smooth blacktop the car will cycle from vibration free to a slight vibration"
"tar strips, cracks, waves, and uneven surfaces will all cause the vibration. Sort of like driving down a washboard road"
"I feel it more through the seat and body then the steering wheel but that has a vibration too. It is definitely body shake and cyclic."

Mine is not from the engine as it only happens when under way. I'm also not sensitized to it as I just picked up the car and notice it right away. I also test drove 2 other SL600s which didn't have the problem.

I was just about to take the car into the shop to start with balancing the tires and looking to see if they or the wheels are out of round when I came across this thread. I haven't seen an update from Mark since his harmonic balancer was replaced. Does anyone know the outcome from when Mark dropped it off at the "Benz 'guru' "? I'm hoping to see what others have done before I start.

Thanks in advance!
Doug

 

Thanks for the great explanation! In my 500, I had similar vibrations that I also felt through the seat. BTW, this was after I had the harmonic balancer changed as part of the MB recall.

In my case, the vibrations were a combination of things. First and foremost, my motor and transmission mounts needed changing which helped substantially, but I still had more vibrations than I felt the car should deliver. My next, and last stop, was to a shop that could provide accurate tire balancing and load simulation, run out, etc., IOW, a shop that uses Hunter's Road Force System. If not familiar with this setup, see...

http://www.hunter.com/pub/product/ba...159T/index.htm

Even though my Bridgestones were almost new and supposedly balanced properly, until they were each put on this machine with a knowledgeable tech at the controls, I was shown how far off they really were. Weights and locations on the wheel were substantially changed, and with that, the last of the vibrations were 'fixed'. Hunter has a dealer locater service at the site above if you want to try them. Good luck!

Bob

 

Thank's Bob, I'll give them a try.

Doug

 

Doug, I think you'll be pleased with the outcome. That said, don't be bashful at the 'Hunter' shop in asking for the best tech. You can't give a stradivarus to a monkey and expect great music...same with these techs. Shop manager should level with you as he doesn't want to do your car over and over...you get the idea I'm sure.

Bob

 

It appears the SL is sensitive to RFV. Torsional rigidity is less good than saloon. Also engine mounts etc are very soft in order to give good level of refinement.
The Hunter equipment is the best solution since it enables the best POSSIBLE level of RFV to be delivered by the tyres that you have.... OTHER than purchasing better RFV tyres in the first place.
Note;Aftermarket tyres MAY not be as good as OE even if the same Brand, pattern etc. Second quality (less good RFV level) are used up on the Aftermarket!

Stuart.

 

I have a '92 500 SEL which also has a vibration.

Themain vibration happens between 45 and 55mph and you can feel it throughout the car. We have recently took it to a MB mechanic who replaced the RH tierod, tightened the stabilizer and balanced the wheels. Now the vibration is worse.

Looking through this thread I have a number of choices but if anyone has any ideas I would appreciate it.

 

Hi.

I repeat....
Wheel and Tyre RFV (Radial Force Variation) levels too high!

It appears the SL is sensitive to RFV. Torsional rigidity is less good than saloon. Also engine mounts etc are very soft in order to give good level of refinement.
I understand that Hunter wheel and tyre equipment is the best solution commercially available since it enables the best POSSIBLE level of RFV to be delivered by the tyres that you have.... OTHER than purchasing better RFV tyres in the first place.
Note;Aftermarket tyres MAY not be as good as OE even if the same Brand, pattern etc. Second quality (less good RFV level) are used up on the Aftermarket!

RFV is the LOADED OUT OF ROUNDNESS of the tyre which can be very different to the UNLOADED out of roundness.

A "laboratory" solution is to skim (prematurely wear away the surface the tyre) OR to selectively mount the wheel to tyre (only works on slightly out of round rims!) to ensure ROUNDNESS when LOADED.

Hope this helps.

Stuart.