bobinyelm

2003 C320 85,000mi

About 500mi ago I started hearing an intermittent faint muffled clicking noise from below the center console.

Since then it's there more of the time- very faint at speed, but obvious at very slow speed as most likely driveline clicking at driveshaft speed.

Unfortunately I am nowhere near where I can even look at the car myself (we are temporarily condo dwellers until we move to a new home 1500 mi away in 4 months).

I don't know even if my car has a flex disc up front or all universal joints, but I am wondering how long in miles I have until real damage is done, and if I have to have it rebuilt/replaced what kind of financial damage I'd likely be looking at.

Could it even be in the transmission tail shaft?

Any other info most welcome as well of course.

Bob

Plutoe

You have flex discs-------put the car on a lift and inspect the running propeller shaft!!

bobinyelm

Yes, I did a little research and realized there are flex discs at both ends.

Given that the noise (light patter at speed, and soft tapping at walking speed, but no vibration of "feel" in the car) is most heard at the very front of the driveshaft (seems to be coming from the lighter compartment behind the shifter), it is hopefully the front flex disc.

We drove home today (I was 200mi from our place when I started the thread), and it didn't make a single peep all the way back, which amazed me in that the last 5mi before parking last night, it was VERY evident, and made me dread driving the car home.

Back when I had numerous BMWs of 70s and 80s vintage, I changed many guibos as Bimmer fans tend to call them, and they usually caused vibration when they got stiff w/ age, but never made noises, but I'd be thrilled if that's the cause. I'd be disappointed if the center universal packed it it at only 85,000mi.

I'll try to find a local shop where they would accommodate a look-see.

So far I've only heard the noise twice (very faint the first time a month ago, and then faint at speed, but very noticible at slow speed), but hopefully any visual deterioration would show itself in a 2 minute "run" on a lift.

johnhef

bobinyelm, I know exactly the noise you're referring to, I myself have heard it on many cars, and now my 215k C320 does it, although I have never looked into the source. It is quite annoying. I dont believe its the flex discs causing it but you may be on to something with the center support bearing. It is a faint clicking rotational noise that increases with speed that sounds like its something right up against the floor of the car. Next time I have my car on a lift I'll see if I can reproduce it, but I'm not too worried about it since this car is getting a driveline swap soon anways.

bobinyelm

Thanks-

Yes, at speed, it's a barely audible flutter sound (I have to turn my head 90 deg and tilt it toward the opened compartment that holds the cigarette lighter to even hear it) , and the last time it didn't go away at sub 30mph- it sounded like a very mild tapping at the shaft rotational speed quite audible through the whole car, but the next morning it was gone again despite the duplicate 200mi drive that had precipitated it the day before.

It does not seem to be related to the amount of torque put on the driveline (makes the same sound throttle on and accelerating, throttle-off and coasting)*.

If it were consistent and repeatable (or I had any vibration with the noise), I'd have some confidence that it could be heard if the car were put on a lift for a look-see or a listen with the driveshaft turning.

Though the car is 13 years old (rubber dries out), it has only 85k miles and has been driven very conservatively-it has never seen more than modest partial throttle and only good roads in its life (high torque can affect flex-disc life based on my BMW experiences where flex-discs on enthusiast-driven cars needed replacement from time to time), so it would seem premature for driveshaft problems (though anything can pack it in early). I've had many MBs since my first '58 180 48 years ago (some W115 and W123 had 300k+ miles) and never experienced a single driveshaft issue, so I guess I figured they were immune to the malady (silly me).

When I wrote the thread, it was making real noise, and I was afraid it was about to self-destruct. Now that it's dead quiet again, I am inclined to just monitor it. Without consistent vibration or noise (which I THOUGHT I was on the way to), I am confident I am not looking at imminent failure, so we'll see where it goes I guess.

Nice to see the W203 wagon image in your signature. I LOVE mine, and you sure don't see many on the road. I regularly get 26-32mpg on regular fuel (more if I use premium fuel, which I don't since I live where it's flat and don't flog the horses), which I tend to attribute to the aerodynamic shape of the car.

Thanks,
Bob

*I once had a U-joint in a Triumph Spitfire suddenly go dry and "freeze-up" (at 35,000mi no less, but it was British, of course) where it made the vehicle feel and sound like one was driving over a highway "rumble-strip", but back then a $5 owner-installed U-joint cured the problem.

Glyn M Ruck

Are you sure it is speed related? If not do all the HVAC controls work properly? Clicking can be a broken stepper motor arm. Otherwise check rear engine/transmission mount. Frequently goes soft. Both PS flex discs for cracks & centre prop bearing.

Other flutter can be intake system noise & clicking = EECS purge valve.

bobinyelm

Yes, it is road-speed (not engine speed) related for sure. I would almost bet it's driveline speed or about 3+ times the wheel/tire rpm, which would be about right. It's a "soft" (non-metallic or non-vibrational) sound, which is why I said a "fluttery" sound. If I didn't HEAR the noise, I would be totally unaware there was anything amiss. No sense in the chassis of "tapping" or vibration you could "feel" at all.

I doubt it's an eng/trans mount, because as slow speed (5-8mph) I shifted into neutral w/ the HVAC off and it didn't change character at all (until it slowed to a stop with the vehicle), so it was the same under zero load, unless a sag places the driveline at an odd angle.

It could obviously be a deteriorated flex disc, and maybe the u-joint or center carrier bearing, but it has me flummoxed that it's not "repeatable" (yet?), so cannot be reproduced with any predictably. I was really expecting it to be noisy the morning after it was its worst ("worst" was definitely noticible, but not that bad) , but the entire next day (and since) it has been utterly silent.

If I can get my step-son's floor jack and a pair of jack stands (he lives here in AZ where we are staying) I will try to get under for at least a look-see for anything obvious about the flex disks, and I will obviously apply pressre to it by hand to see if anything has any play. With all the plastic shielding underneath, I'm not even sure much is very visible though w/o removal.

Bob

johnhef

Think of a kid with a baseball card fluttering against his front wheel spokes on his bike, but more muffled. It's like that. Mine does have minor cracks in both the front and rear flex discs so there is a slim chance it could be those but I don't feel that it is based on the sound. I'm still leaning more toward the center bearing.

bobinyelm

YES!!

That is the sound EXACTLY!

In fact I was going to use that to describe it, but thought others might not have done it, or remembered it.

But a soft engagement of the card and spokes, so that you wouldn't even notice it inside the car unless you were already aware, or turned and lowered your head toward the center console.

Not at all something I would normally associate with a bad bearing, or similar to the failure of flx discs in BMWs in past years.

On the very few (fewer than 5) times I heard this before, it went away as soon as I slowed below maybe 20/30mph

Continuing the analogy, has yours ever continued to a stop where you could hear the card slowly clicking off the wheel spokes as you slowed to a stop? ( As I said, mine only did that once, then the next day didn't make a peep on a 200mi drive.

How long has your car been doing this? Has it become louder, more frequent, or constant? I am trying to predict how mine will progress.

I am leaning toward postponing action until we complete our move and I am where I can pull the driveshaft myself.

I'd obviously replace flex discs, and the bearing is replaceable, though the simple Haynes manual I have says it's tough to get off. I did one on my 1 ton Cummins diesel last year, and I ended up cutting the bearing races with a disc on a die grinder (cut almost all the way through so as to not damage the shaft, then tapped the "cut" with a hammer and chisel and they split open cleanly and slid right off) rather than damage the shaft, and installed the new one with a proper length/diameter steel pipe and it worked fine.

I appreciate you sharing your experiences. It appears this phenomenon may not be the normal failure sequence based on the fact you are the only person duplicating the noise.

johnhef

I've only had the car on the road for a month, so can't say for sure how long its been doing it it. I want to say initially it wasn't but I can't be certain. I've heard the noise in countless other customers cars, however no one has ever complained about it though, so I've never had a reason to pursue it... I just pick up on odd noises like that.

I'll drive that car again in a week or so and may throw it on the lift and see if I can track down anything. I'm not a whole lot worried about it like I said because that wagon is getting the C32 drivetrain from the wrecked car I bought.

bobinyelm

Ah, well it's comforting to know you've heard it frequently in other cars (and I guess it didn't lead to grief).

This is the first W203 I've had or ridden in for more than just a "spin", and I can't say I ever heard it like this in any other car (MB or not), though I've heard/felt other flavors of driveshaft noise/vibration.

If it hadn't continued at low speed this one last time (where I could hear individual noises with each driveshaft rotation) at walking speed I would have just dismissed it more effectively myself.

I'll just monitor it and get under when I have a chance, thanks. Hopefully it's nothing in the transmission tailshaft, which is about under where the noise was making itself noticeable.

If you think of it, post a note on the thread when you pull the shaft w/ your swap to let us know if you see anything notable?

Thanks,
Bob

FStephenMasek

Our 2002 C230K has this exact problem. I did search, but missed this thread until somebody else found it. What solution was found?

bobinyelm

It's a work in progress, but hopefully one of us with the problem will come up with something definitive along the way.

The more people who see the thread and check-in, the greater the database and chance someone will find the solution.

Curious- Does your noise even continue to a stop, or does it only make the sound at speed, then just fade out as you slow?

FStephenMasek

It fades, but almost to a stop. Finding a quite road to listen is part of the problem. I tried coasting down a hill with the engine off, and the sound is still present. It starts after about 30 minutes.

bobinyelm

Yep, exactly, until last week when it continued to walking speed, when I could count the soft (non-metallic) 'clicks' (always before it became inaudible below maybe 30-45mph).

The next day, and since (again) not a sound from it-utterly silent at any speed.

Things rarely "fix themselves," even briefly.

I'm sure it will re-appear, just not predictably (yet).

FStephenMasek

Our car is also "haunted." We drove from southern California to Las Vegas on Sunday and back on Monday and did not hear the sound. Today the sound was very prominent.

bobinyelm

What I find odd in these cases is not that driveline components wear out, but that the symptom is so variable and intermittent.

What we haven't heard yet is from anyone who changed one or more components and had the sound successfully disappear completely.

FStephenMasek

Since the sound continues almost to a stop, it seems most likely that it is from a rotating part(s) in the drivetrain or at the wheel(s), not some loose part moving with engine vibration or the air currents passing under the car.

bobinyelm

Agreed-
The frequency of the noise when present is a few times the rotational speed of the wheels, so I assumed it was occurring at driveshaft rotational speed.

Since it stays constant with road speed (even w/ the transmission in neutral), it's not engine rpm repeated, again leaving the driveshaft as the likely culprit since the noise is likely at wheel rpm X differential ratio.

bobinyelm

Yep, two giubos, one U-Joint, and a carrier bearing.

I used to change out these on BMWs, but the ones on MBs seem more durable and I really don't remember problems on my earlier Benzes.

The Bimmer ones never made sounds quite like I am hearing now, either. But maybe they have a different failure mode.

FStephenMasek

One tire (almost new) got a nail, so I took some photos while I had the car jacked-up (with safety stands)


back of the rear flex disc



front of the rear flex disc



front flex disc



left CV joint boot at the differential is clean



right CV boot at the differential has a light coating of oil/grease, but no break visible



some oil on the transmission pan