Concretebrew

Wheter standing or moving between idle and ~ 2000 RPM's there is a whining sound coming from the drivetrain (Sounds like the front of the engine). It is slight but enough to drive me crazy, At speed the sound is gone and the car is whisper quiet. I've replaced the serpentine belt and all the idler pulleys an tensioner bearing as well as the ABC pump. The dealer told me it needed a "fix" in the form of a dampner for the ABC pump but it did not make any difference. Any ideas or similar experiemces? The noise is audible even at idle (800 RPM) and the engine is smooth. Whether hot or cold, the whine is there, Driving around town when it is usually running at 1000 to 2000 RPM's is very noticeable on acceleration or deceleration and the noise pitch does not change it it louder or softer but even. It is driving me crazy and I am tired of paying the dealer to "try" things. Thank you!

AlexSafrica

Hi, I have exactly the same problem on my ML 63. The dealer told it can be the alternator. I have changed the same pullies but no luck.

Concretebrew

Boy, I would not go for the dealer "thiking" it is something.I fell for it when they "almost" assured me it was the ABC pump and $1,500.00 later they apologized for giving me their best guess but that was the extent of how sorry they were.I am now looking more towarts either the engine or exhaust not being independently suspended and barely hitting the chassis. But who knows! A dealer won't touch it unless they guarantee it will fix it.

biker349

possible engine mounts?

C Rob

I have the same issue and like you it is driving me crazy. My dealer said they hear the whining but it does not affect the performance of the car.

2014CL600

I couldn't remember where I saw this post but I posted it on the other MBZ forums. The noise is your electronic diverter/smog pump. If the noise doesn't quiet down after warm up then pull the relay out so not to burn up the unit and the relay both. You will have to replace your pump. They pump isn't expensive but if left to make that loud insane screech then it will eventually lock up and burn out the relay. It is easy to get to and you can do it yourself or have it done. My service adviser told me it is common on the 600's that they go bad. Good luck with your issue.

leodangelo

I have the same problem with my CL65. Can you tell me where the relay you are referring to is located? Any advice is appreciated....

-LeoD

2014CL600

I do not have any idea. Call your service adviser and ask him or her. They will tell you. I take it your isn't shutting up. Just replace it yourself. Buy it from any online parts retailer, they are made by only one company and they bolt on and plug in. Easy to do, so my adviser told me. I asked for you guys. I am sure one day my time will come. Sometimes mine is loud after sitting but it does go away. He said the bearing goes on them.

leodangelo

Mine is getting louder and louder... especially when it's cold out... I have the WIS I will see if I can find the relay and post what I find here....

2014CL600

That would be very nice of you. I think it is important that you replace the unit instead of trying to circumvent the system. It might give you a rich code and cause all sorts of issues. Yes, the cold does cause them to become louder.

leodangelo

I will replace it for sure if I can figure out what to replace. I took it to my mechanic and he thought it might be any of (idler pulley, ABC pump, alternater, etc...) I don't feel like taking my check book on a fishing trip right now ;^) as my car runs great and has not thrown any codes, etc... YET.

-LeoD

2014CL600

It wont until it blows the fuse. If it is shrieking like a high pitch noise that you have never in your life heard before then it is for sure the air injector pump. Mine did it after sitting 6 months but went away within a less than a minute. I inquired about it and my service adviser told me what it was. The noise was almost defining.

3ktt

Mine did the same it was the pulsation damper, they also replaced my torque converter at the same time so I'm not sure what exactly was the reason for it but they said it was the damper. No noise since

2014CL600

Your pics didn't come through repost them

2014CL600

someone posted accumulators needed to be replaced. They do not make any noise. If they are bad the car is bouncy but that is it.

Concretebrew

Wow! Looks like I started something interesting! Sorry I haven't been around, but since fighting my whining noise, I've had to fight cancer as well. In any case, needless to say my CL still "Whines" and it is worse now that it is Winter although it quiets down when it warms up.

At least in my car, it is not a high-pitched screeching noise ans what I have been recommended to do, is run the car without the serpentine belt. I think that will be best as it not need run but a few seconds for me to tell if the noise is gone or not. Has anyone tried that?

I have discussed this with several people I know and trust as knowledgeable when it comes to high end cars but none are experts on this particular vehicle and if I tally the scorecard I come up with the automatic transmission. Possibly the planetary gears or the the front pump.

I still need to have the exhaust checked as there is an MB technical bulletin addressing that and at least from reading it, it sounds like the noise is similar. But, frankly,I doubt that or an engine mount(s) are the problem as I had the mounts checked at 50K miles when the noise was not there and the transmission mount was shot. Replacing it smoothed the car so much I had not realized how bad it actually was but it never caused any noises.

Thanks for everyone's input; as soon as I figure this out and it makes sense (Not sure about a damper...) I will post it.

Haylands

Hi

I have the exact same low pitched whine under 2000rpm as you but mine is a only a V8 so I doubt it's the something the serpentine belt runs... I also have changed the belt and idler as these were worn but the noise is still there....

The pulsation damper is next on the list unless you have found the problem yet???

Cheers

AndreNY

this seems to be a typical issues if its not the pulsating damper it is the hydraulic line from the Pump

Haylands

Thanks for the info, do you know which line it is, and is it a case of just replacing it or does it need cleaning or something??

Thanks

Pete

AndreNY

Hey Pete demepnding on the VIN you have it most likely will be 220 320 43 72 this line is off the pump and it comes very close to the tranmission so in order to charge it the tranmission MUST be removed, The line acts as a high pressure fluid line that if clogged or leaking will cause the car to hum on start up or low RPM. The hose is about $500 at the Stealer

ctravis595

i agree that it could be any one of the components in the s belt system. you could add lubricant to each pulley one by one to see if the noise goes away. if this doesn't solve the issue then i would try to pinpoint the noise better.

use a long screwdriver (or similar stiff object that will carry vibration) and place one end on your ear, the other end moving around different components in the engine bay (while someone is revving up the car) and with this technique it should be easy to find out where the noise is coming from

does the sound happen in both park and in drive?

ctravis595

i completely disagree. i removed this exact ABC hose that goes from the abc pump, over the transmission, to the pulsation dampener (i think that's what it's called) with the transmission in place.

you only have to remove the 1 bellhousing bolt holding the high pressure line onto the transmission with a bracket. disconnect it at the ABC pump side and also at the pulsation dampener side and the hose will slide out from either the engine bay or beneath the car. removal of belly plastic pan is obviously called for in this situation

edit: having the car's hood in it's true service position (instead of just being open) will help a lot with accessing the bellhousing bolt holding the line to the transmission. utmost cleanliness is supposed to be demonstrated when dealing with the hydraulic fluid lines

Haylands

Hi

Thanks for the replies guys... had heard it was the CL65 that needs the trans removing to get the pipe out....

Anyone know why this pipe makes a noise?? the only thing I can think is that it's dirty??? in which case could you not clean it out??

Cheers

hegar817

How long was the job to get the hose replaced? I have a mechanic that will charge me per hour labor rate and want to make sure he does not over charge me for excess time. Also, would you just bleed the system by cycling the ABC button many times?

Thanks

Ifari

This above is the correct solution......(P/N 220-327-0215 air reservoir)

The MB STAR SERVICE Manual Library DVD in the DTB section states....

The ABC Pulsation Damper/Accumulator can correct a 'hum' or 'drone' sound. If a 'hum' or 'drone' sound up to 2000 rpm is heard, but gets drowned out by the sound of the engine above 2000 rpm, it could be as simple as the hydraulic lines contacting the body of the car. Have the lines inspected and if they clear the body, then replace the Accumulator.

The manual also SPECIFICALLY states that replacing the ABC pump will NOT correct the 'drone' sound problem.