superfast

Hi there, I have an 02 CL500, purchased about 10 years ago & currently @ 115k miles. I have been taking great care of it so it has been a great car with everything in good working condition, except there's a low level rumbling noise like rolling thunder when car is driven at low speed. The noise has always been there ever since I bought the car. Initially, I thought the noise was coming from the tires as the 2 front tires were half worn so I replaced all 4 with brand new tires but that wasn't it. I later replaced all 4 ABC's accumulators along w/ the front UCAs, LCAs, strut bars (some called it lower brake reaction arms), 2 front rear subframe's bushings (couldn't get access to the other 2 rear subframe's bushings w/o dropping the subframe), both bottom rear's strut bushings & the 2 bushings at the rear wheel hubs/knuckles but the noise still there. I've also inspected all the suspension's bushings in the rear but everything seems to be fine. At this point, I'm running out of idea so just wondering if any members out there may have experienced the same noise on your cars & have a fix for it. Please advise. Thanks.

superfast

Took the car to an Indy Mercedes repair shop that has a 4-channel chassis ear device. We hooked up the 4 wireless sensors to various locations under the carriage but after 4 hours of driving & listening, still couldn't pin point the noise source. As stated, I've replaced pretty much all of the suspension components, other than the noise, the car is rock solid so I'll leave it alone. Just have to crank the radio up to mask the noise when driving & learn to live with that or trade it in for a brand new S-580

HopefullyE63

I had a noise I chased for about 8 months that drove me absolutely crazy. Made the car sound like a POS despite the magical engine noises. I did the front and rear subframe bushes among a few thousand (20)+ worth of work mostly to the abc and ot suspension. The last thing was re-replace the rear struts. Thats what finally did it. The drivers rear strut was rattling and it translated to a dull knocking thumping. There are posts here about people putting a urethane "ring" in between the strut and strut tower. Something up there gives out and makes the thing rattle. Hope this helps

superfast

HopefullyE63- I had the top strut mounts on all 4 struts shimmed with rubber donuts in the front & big aluminum washers in the rear a few years ago while trying to locate the noise source but it's still there. The 4 channel chassis ear device that we used last week actually suggested there may be something lose at the top of the rear struts so when I get a chance, I'll take another look there. Thanks for the info. Btw, what year is your CL600 & did you replace the struts w/ OEM or re-manufactured Arnott?

HopefullyE63

Hey Superfast. 2003 CL600 sport pkg designio mocha black on black. Stunning color. I replaced the two front almost immediately after buying the car with Arnott reman units. The noisy strut on the drivers rear I replaced with a no name "rebuilder" shipped directly from you know where cheap and looked good, but the jury is out.

I'm getting a new noise that sounds like a plunger squeaking when the car hits a dip and loads the suspension abruptly. Maybe a bad block but I rebuilt it and the car stays level. I have a post up hoping for some ideas. The passenger side is a take out from a CL55. That may be the one failing and I think I'm hearing it in the block but that's speculation at this point. If it's the "new" strut failing that would suck.

If you are going to get a new unit go Arnott. They have a rep and are worth price IMO. Really should have gone coil over from the start with my car, it's not a perfect example. Won't be a collector. I have more money in it than would pay for a perfect CL65.

superfast

Mine is also black, ash interior w/ CLS 18" stagger wheels so it looks great too that's why I still have it despite the suspension noise. Anyway, if you're getting a squeaking noise (not clunking) then most likely one of your rubber bushings is drying out so here's what you should do: Get a can of WD-40 Silicone Lubricant then go underneath & spray all of the bushings & plastic parts then the noise should goes away. Make sure to get the can w/ silicone as the regular WD-40 only disperses water. Your valve blocks should be fine as you had mentioned yours stays level & doesn't sink. When you replaced the struts, did you do a rodeo or just a normal flush to get all the air out of the system by putting the return line into a bucket?

HopefullyE63

The cars are truly beautiful. W215 Cl is one of the best looking coupes period. Add the performance and that's why I believe we suffer the way we do.

Yeah I rebuilt both blocks on the CL and the front on the SL55. Its not that kind of noise. Its more of a bark. Also coincides with higher than normal loads like over a dip elevation change. The noise comes from the left drivers side more or less black or Sturt area. Has anyone had the solenoid on the block fail?

superfast

I totally agree w/ you that the W215 is one of the best looking coupes Mercedes-Benz has ever made. It looks ways better than its W216 successor that's why I had a hard time parting way with it. Recently, I was thinking about getting either a 2018-2020 S63 or a new 2021 S580 so I posted the old CL on Craigslist but then immediately took it off as I couldn't bare to let it goes. I guess you can say that I have an attachment issue. I currently have 6 cars, bought my 97 Lexus LS400 24 years ago & still have it to this day. At 255K miles, she still drive like a brand new car.

In regard to converting the ABC to coil over, I too have thought about it but I don't think it's a good idea as these cars are very heavy & have no sway bars. The ABC system functions really well when it's properly maintained so just keep up w/ the regular preventative maintenance by flushing the hydraulic fluid & replacing the filters once every few years to keep the system clean then it will serve you well.

What do you think of the new S-Class? I'm a bit disappointed with the new look. It's loaded w/ new techs, however the front end is more rounded so it looks like an Audi & the tail lights just look way too small for me for a big car. The interior is always nice but I'm not sure about the instrumentation panel as the traditional has been replaced with the 2 iPads & their placements are so weird w/ no flow at all from one door to the other. Oh well, time will tell if it'll grow on me.

superfast

Btw, when did you rebuild the 2 valve blocks? Since you've mentioned your car is level & doesn't sink then I'm pretty sure both valve blocks are fine. What about the left rear strut? How long has it been since you replaced it & when did you notice the new noise? Do you feel any looseness or see any signs of wetness on top of that strut? If none of the above then there's a possibility that the rear accumulator may have been blown so it's no longer capable of acting as a dampener when you hit a big dip on the road & the car makes noise so you should check there. Did you experience any fluid overflow at the ABC reservoir recently? If so, you definitely have a blown accumulator. Initially, I was also thinking you may have air in the system between the left rear strut & the rear valve block but the ABC is a close-loop so the fluid is constantly circulated throughout the system when the car is running so I don't think the problem is there but it wouldn't hurt to do a flush & replace the filter once you've ruled out the rear accumulator. The easiest way to test the accumulator is by gently inserting a small wooden stick w/ a blunt tip into its opening. There's a membrane inside the accumulator (ball) & its function is to seal & prevent the nitrogen gas at the bottom half of the ball from escaping. If the membrane feels soft or completely not there then you've found the problem. Good luck.

HopefullyE63

I did swapped all the accumulators when I got the car less than 6K miles ago. Hard to put miles on a car in PR. Relatively small island. The blocks could be it. I'll check the accumulator as it's not an expensive item. I flushed three times in the last 2 years with an extra filter change in between. I did a very brief rodeo with my star laptop. Car feels uniformly soft on in the rear strut. No more oil than the usual under the car Like they say "if it aint leaking oil there aint no oil in it"

I really like the new s class convertible. If I do that it will be a pre owned car. Those just plummet in price like crazy off the lot and it seems most of them are run on the flat in FL. They look bas *** especially the AMG ones. I drove a friends debadged s coupe conv think it was 2018?. Designio interior not amg but sport and it was really a beautiful ride. I'm ready to part with mine. It's going to go cheap. I'll miss it very much. If I had to do it all over, and I might, it will be a PRISTINE books and records CL65. They are getting so cheap. Hard to beat for the style and performance.

superfast

I had also replaced all 4 accumulators on mine w/ brand new OEM & one of them busted after only 10K miles but it's about 8 years old so age can play a bigger factor than mileage. It happened last year when my wife & I were on vacation & my son took the car out for a spin. The ABC light came on right after he started the car & the pressure from the busted accumulator had no place to go so it pushed the fluid out at the reservoir & the light disappeared after a short drive. When I got home, with the car running, there was a constant whining noise so I knew right away it was the pulsation damper, the one right next to the front passenger wheel so you may want to check that one too.

Speaking about vacation, I was a Senior Scientist at an Aerospace Company here in Southern California. Two years ago & after 36 years with the company, I've decided to retire young & was able to convince my wife to retire with me so we can travel & see the world. In 2019 & early 2020, we've visited a total of 22 countries & 50+ cities in both Europe & Asia. Now that we have the vaccines, we can't wait to go travel again & PR is also one of the destinations that we'll be visiting in the very near future. Life is too short so we've got to enjoy life everyday at the fullest.

HopefullyE63

Wow that is amazing! PR is absolutely magical this time of year. The christmas winds and high 60's low 70's weather plus awesome food. Easy to get to as well. It's opening back up steadily. Not quite Florida but trending in the right direction.

My dream goal is to sail the med in a good size catamaran. If I like that then maybe trans Atlantic back thru the Caribbean and around the other side like you say life is short. The electronics and weather tracking has gotten so good it's much safer to do it.

superfast

Thanks for the info. I'll make a note of that. When you get a chance, you should pull the trigger & go for it but plan ahead then it'll be fun. Happy New Year to you & family. Take care.
John

superfast

I spent the past few days troubleshooting the noise & finally was able to find the root cause. Both rear struts were lose at the top. A few years ago, I've shimmed the gaps underneath the rear strut's top nuts like I did with the front struts, however the shims (metal washers) that I used for the rear weren't thick enough so both struts were still lose. I ended up adding 2 more thinner washers on each side & now the thumping noise is gone. While I had the car on jack stands, I custom made the strut's dust boots out of heavy duty tarp but still soft enough to compress under load & covered all 4 struts to prevent dirt from getting in. This should save the struts for at least a few more years. Mission accomplished!

HopefullyE63

Yeah very cool! So the do the added washers act as increased friction surface so its harder for the strut to shake around?

superfast

The added washers are used to keep the top of the strut shaft stationary.

S55L

is there a diy for this?