kitaman

Hi guys,
I need help in figuring what's wrong with my car.
I have a 2012 E350 with 14k miles on it.
It makes a clicking sound when i drive around 10-20mph.
I have take it to the dealer twice but they could not figure it out.

this is the video:

PeterUbers

Watched the video (thanks for posting that -- a video is worth a million words)

Does it vary with the MPH? You seemed to be driving at a steady rate
Does it get higher pitched with MPH before it disappears at 20mph?
Does the road noise drowned it over 20mph or does it just go away completely?
Does braking affect it or make it worse or make it go away?
Does turning at 10-20mph change it?
Does the RPM of the engine change it? -- Have you changed RPMS with the manual shifting?

Sounds like an axle to me or a bearing, less likely a brake pad/rotor, less likely a suspension issue

What did dealer possibly think it way -- did you road test with them, and did they confirm they heard it too?

kitaman

Hi peter,
Thanks for replying.

So, the noise was most intense when the engine is cold and you drive it directly.

The noise does varies with MPH, Slower speed will lower the clicking noise speed.So does higher speed.
When I drive at faster speed( above 45mph), I can't hear the noise( I think the road noise drowned it).
Braking,turning and the RPM doesn't affect the noise. However, I didn't try to use the manual shifting.

The dealer's mechanic said that the sound is related to the pump noise and it is normal, but I doubt it since it doesn't make this noise before.



I don't know how to force them to fix this. I am thinking to fix this in another dealership since they can't fix this issue.

I saw you come from Chicago area, can you recommend me some good dealership that I can take my car to? I live in champaign, IL

Thank you before.

ss3964spd

"Noise is the high pressure pump" - AKA the transmission pump. If it is the HP pump there's no way it is normal.

Does it vary by MPH or RPM? In other words, start out in first or second gear but manually hold the transmission in 2nd until you hear the clicking. Hold that steady speed then manually shift the trans into 3rd but without gaining speed. If the slicking slows down then it's engine/trans related. If the clicking remains constant it's something else.

Another test. Does the clicking get louder the harder you accelerate? Is the clicking relatively quiet if you accelerate gently, but louder if you accelerate hard?

faz999

I am glad you bought it up i have 2012 42k miles i hear very similar noise travelling between 10 - 29 mph

then it goes away. if you drive close to the curb or a wall the noise is louder i believe noise bounce off, if you drive in the middle no curbs or wall noise is very limited and you can't hear it i drive on the highway no noise.

It coming from both side of the front left and right wheel, again mine is not as loud but if you concentrate you can hear it.

i did bring it up with the dealership in Lincolnwood IL and they said they hear the noise but could not find were it coming from they had it for 3 days and came back with no fix,

recently i have not heard the noise i do not know if it will come back but definitely strange

if the windows are up then there is no way you will hear the noise...

rovinrail

I've got a 2014 E250, and I get what sounds like a similar clicking noise-- also at low speed while driving with window down up an alley. Been wondering... seems to be a steady click.

PeterUbers

I use Naperville, il Benz and so far they have been very helpful.

Sounds like an axle to me or some part associated with it

Quadcammer

since when is the high pressure pump (typically the high pressure fuel pump in DFI engines) a transmission pump?

ss3964spd

Since when isn't it? Don't torque converter style automatic transmissions have a high pressure pump? Given the symptoms presented so far I made a guess. As did you.

But since you suggest the HPFP I would guess that it operates at a much higher RPM - assuming it is a rotary type pump, and would be independent of road speed. If it were the HPFP I would further guess that the clicking sound would be reproducible simply by revving the engine with the car sitting still.

KEY08

That is definitely a weird knocking noise. My old E500 sounded like that on start up, but it went away quickly as the engine warmed up. Remind me not to buy a DFI engine if the pump makes that kind of noise all the time. That would drive me crazy.

Quadcammer

The standard georotor tranny oil pump really isn't considered high pressure in my eyes, nor have I heard it referred to as such. It would also have to be pretty knackered for it to make that kind of noise.

I'm not up on the way these high pressure fuel pumps work, but I'm guessing that the pressure level may be related to load, which you wouldn't get much of when the car is still. That said, it would be load related, not necessarily rpm or speed related.

This points to an axle of some type.

Does the noise go away while turning?

ss3964spd

It does sound rather like a CV joint on it's way out, which normally show up under heavy load or when turning. Since it wasn't specified as such I assume the car doesn't have 4M, so no front axles. Regardless, a clicking CV joint would be solely MPH related.

Think the OP needs to perform a little more testing to narrow it down.

Get the car up to the speed where it starts the clicking sound. Put the car in neutral and let off the gas - allowing the engine to return to idle, and allow the car to coast. If the sound goes away immediately, engine/trans. If it doesn't, driveline.

KEY08

Geez, the shop even performed a "world Class Inspection" and came to the conclusion it's normal.

PeterUbers

Lol, nice catch.... Time to totally avoid this stealership!!

Jack661199

I have the same problem on my W211 03 E320 it's only at low speeds and also in park right when I start the car up but applying the breaks will stop that sound. For me I'm clueless as what it might be, also it seems like it's coming from the driver side

kitaman

I have tried the manual transmission today, The clicking didn't slow down even i shift the gear from 2nd to 3rd. The clicking still remains constant.

Actually the clicking didn't get louder by accelerating, If I accelerate, the road noise will cover it and it getting less intense.

kitaman

Okay maybe, I'll try to get my car there to get fixed. They offer a loaner car right?

kitaman

Okay, I'll try the neutral thing tomorrow!

PeterUbers

Heck yeah you'll get a loaner... Call ahead to make an appointment to make sure you get one

Arrie

Sounds like engine noise to me something with engine revolution. This should change with changing the engine speed using manual shifter pads with keeping the car speed constant. If it does it is engine related and not transmission.


Who does your oil changes? An easy trouble shooting trick is to change engine oil and make darn sure the correct oil is used. With wrong oil you can get valve lifter(s) making sound like that.
You better check before it is too late. Sound definitely is not normal no matter what any dealer says.

kitaman

I've tried the shifter pads while keeping the car speed constant and the sound is still there.


I always go to MB dealer to get my oil change on time.
Yeah I want to go to other dealership since my dealer is sucks LOL.

Arrie

Yes, the sound would be there but does the frequency of the sound change.


If you find a quiet road where you can set your cruise control to 25 or 30 mph when you can hear the noise. Then with the paddle shifters lower the gear meaning the engine will rev up keeping the car speed constant. Does the sound frequency go up too, i.e. does the "beating" of the sound go faster? If it does it is engine noise.

Quadcammer

If the noise stayed at the same rate despite the the increase/decrease in revs (at the same road speed), it has to be propeller shaft, axle, or wheel hub related.

I had a bolt lodged in my tire that made a ticking noise.

I would probably lift the car and spin each wheel by hand to see if you can hear it.

ttoE550

To add to quadcammer I've had bolts, nails, and rocks (caught in the treads) make clicking noises. In my experience, the acoustics can be misleading and it could be coming from a completely different wheel. With sound deadening and all that it could be a function of how the sound gets bounced into the cabin. I'd check all the tires. But it depends, as others noted, how the sound varies with speed and rpm.

Oh yeah, tire pressure changes as the car warms up, which might change the intensity of the sound.

ss3964spd

The comments about things being stuck in the tire tread is definitely valid; the tires on my pick up truck grab and hold onto gravel like crazy. Get a large enough piece stuck and it will sound a lot like that.

However, I keep going back to what the technician said. Would he really diagnose that sound as coming from a high pressure pump if it were actually just something stuck in a tire tread?

Hmmmm.