Just that drive shaft being off-balance can cause the noise but usually it is the U-joint bearings that are going out. They may feel just fine if part is not taken off of the car for proper inspection. It can be humming a long time before it suddenly gets very loud and then...BOOM!

 

do note, most all driveshafts are balanced at the factory as a whole, so before disassembling the two halves at the spline, be sure to mark them so you can reassemble them aligned correctly.

 

Thanks guys, I think the prop shaft is likely the next spot to check if this doesn’t fix it.

When I took the picture of the brake rotor a few days ago, I also stuck my phone up into the axle area towards the diff. You can see the leak on the passenger side axle. One side is clean, the other has gear oil all over it and if you look hard enough, you can see a little puddle underneath of it starting to form. So....

 

FIXED!!!

A combination of the front differential needing service and the wheel bearing. Mostly the wheel bearing. She's as smooth as glass and quiet as a church mouse (but not a Lexus, which is fine by me!)

 

Great!

I was under the impression you had already did the wheel bearings and that didn't make an improvement. Then you spotted the oil leak... or were both done at the same time and now the droning is gone?

Did they check how much fluid came out? I think its only like 0.9 - 1.0 qt.

 

We did the bent wheel first, didn't eliminate the noise. Then we did the front rotors and that helped with the noise and allowed us to hear it more directionally. Then we went for the wheel bearings and I asked to change the front diff fluid. That's when we caught the leak as they had a good portion the underside removed to service the differential. Not a lot leaked out, I'd say maybe 15% to 20%, but the fluid was definitely ready to be swapped out. The old had metal shavings in it, so it had gotten low enough and worn out enough to start degrading the differential, but didn't destroy it.

The car is buttery smooth now and the power delivery is also slightly more smooth. No feeling of dragging anything or burdening the drive system. Effortless rolling I guess is the best way to explain it. I can tell that what noise is left, is the tires because they haven't really been put to work since November and need to be run hard to heat up and smooth out again. Got some slight flat spotting that I suspect will go away in about 100 miles of highway driving. The tires on this car (the Conti's) are holding up exceptionally well by the way. The tread depth still looks close to new after 25k miles that I've put on the car since I bought it in 2017. I have two that are original from the CPO purchase, and two that had to be replaced along the way from road damage.

Loading up the car tonight and hitting the road for a near 3,000 mile road trip with my son tomorrow in it. Looking forward to the drive again!


....but in classic Murphy's Law world - that damn "pre-safe inoperable" error message keeps coming back on! It's my driver's seat belt latch. I actually have a new one sitting at the MB dealer that I forgot to get this week and just don't have the time to get it. A healthy dose of electric contact cleaner spray down into the latch seems to shut it up for a week or two. Stupid thing makes me laugh now after all of this work, we forgot to get that fixed! I presume it's like my door ding at this point. You know the drill - get one ding and if you leave it alone it'll be the only one you'll ever have. Fix it, and the car will be hit by a meteorite the following week....

 

That is great news? This thread with your information is one of the best I have read with a good end result.

Happy trails and,

Thanks for all the good info you gave us!!!

 

Thanks Arrie for the nice compliment! I hope my posts will help others that seem to cross this bridge sometimes too. I think at the end of the day, from what I’ve learned during the past two weeks - if it looks like a duck and it sounds like a duck, then it’s probably a duck. If the sound folks hear is strongly suggestive of a wheel bearing, then I’d look to the bearing despite if the wheel itself is not showing the other classic signs of a bad bearing (loose). Mine were tight.

interestingly enough, there was an old post on here from years back of folks being able to adjust the bearing to tighten up the feel of the front end. I don’t think we can do that on the 212, but the end result for me with two new bearings is a more connected and firmed up front end feeling. Not to say I had some slop in the steering, it was fine to me, but it just feels better now, like a new car feeling. Very precise.

I’ll likely grab those flex couplings and center bearing on the driveshaft as a preventive maintenance measure sometime later this year. At 7 years old now, and rubber being rubber that lives in a true 4 season climate, I suspect replacing them would be a further update to keep her as new as possible.

As long as the transmission doesn’t crap out, this is my sedan vehicle for as long as she’ll have me. I do love it. I see well maintained 211’s still roaming about quite frequently and think “wow, that car is probably 12 years old and look how nice it is”. That’s what I want for mine. In 2029 when it’s 15 years old, I too want it to be that older Mercedes sitting at the light and folks thinking the same thing. I think it can get there for sure.

right now, we’re loaded up and heading down I-81 towards Savanna GA, taking back roads to avoid 95, and enjoying the pretty spring weather in a truly world class German gem!

 

I dont know if 4 matic, but for my RWD it is adjustable. I did it some months back, from a was 0.04mm I set to 0.01mm.
WIS stated 0,01 - 0,02mm as the target.

At 0.04mm I can actually hear the freeplay tick-tick sound with the right method of wiggle and extension "arm" to amplify my limited muscle strength.

 

These cars correctly maintained go a long way. Mine is 11 1/2 years old, has 180000 miles on the clock and engine still does not burn a drop of oil. I change oil every 5000 miles as it is very easy job and low cost insurance for the motor.

Car look like new in and out other than some rock hits in the front paint and the steering wheel leather has cracked all around.

Can never sell it as it has no book value. Will probably give it in family when time comes.

 

Soooo much better now, but making one change now that I can hear the car better. I’ve got a hodgepodge of different aged conti pro contact tires a round the car. I agree with my indi that two aren’t 100% right. I’m a Michelin guy, and the conti’s are coming off as I speak for pilot sport AS4’s all around. I know one of the conti’s has slight wheel hop, and another is showing signs of cupping. On certain road surfaces, they don’t necessarily roar, but they don’t sound like healthy tires either.. I figure what’s another $900 to basically reset the tires all around with the brand I personally like the best after all of this work...

Long drive this week, but man if there were ever a car meant to eat up the miles at 80mph, it’s have to be this one. Just a nice place to be..

 

80 ? hah, the other day I was on a wide open almost empty road in good condition, just cruising along listening to some laid back jazz, glanced down, and the speedo was reading 110. WHOOOPS! slowed down, and 75 felt like 35.

 

Yes, I have the same problem frequently, coming down the mountain on 17 to the ocean is a blast though!

 

in the 40 or so years I've lived around Monterey Bay, I've seen *WAY* too many insane things on highway 17 to ever want to go much over 70 on the hilly part, I don't care what I'm driving. several of the accidents my wife and I have been in involved us having to stop for spun-out car, and getting pounded from behind by multiple other vehicles who didn't/couldn't stop in time. my wife had a very nice Volvo 960 wagon totalled that way, she full stopped, guy in Mercedes 124 behind her smacked into her so hard she had whiplash neck pain for 3-4 years. I slowed and stopped my Jetta GLI while watching a BMW 325 do the 'twitch' then spin thing, guy behind me had plenty of time to slow and stop too, then HE got tail ended HARD by multiple big pickups and SUVs that pounded him into me. I was declared car #1 of a 20+ car pileup, near Valley Surprise northbound (the BMW that triggered it wasn't damaged and drove off, so wasn't counted). amazingly the jetta (fairly new) was fully repairable to my standards, but I had to pay for 50% of the OEM exhaust system because the insurance companies claimed a 50K mile exhaust system is 50% worn out even tho it was fully stainless steel. then there was the time, musta been mid 80s, we had a TR-6, were driving top down on a clear day, someone scraped the center barrier at speed and we were showered in sparks like from a grinding wheel, oh boy. gads so many stories from that hill. late 70s, driving southbound, i'm driving a friend's mom's early 70s Mercury Vomit-er-Comet, the one built on the Maverick chassis, probably the worst car I've ever driven, with bad brakes,, and bald tires, and we got caught in a massive deluge of a rain storm that the wipers couldn't keep clear. I truly thought we were going to die that night, going 30ish in the right lane (oh, it was at night, and did I mention the dim headlights?) and having ya-hoos flying by way over the speed limit in hydroplane conditions, up to an inch of water on the roadway.

that mountain used to be full of off camber turns, and even turns that would start with a proper bank and midway the outside would drop and turn into a negative bank, that would throw the suspension of a less than optimal car way outta whack if they were going fast. There used to be an average of a serious crash a day on that 12 mile stretch of road. I dunno what the current statistics are, I haven't commuted regularlly over it in 10+ years and always try to time my trips for off-peak traffic times

 

Yes, my engineering firm partner and best friend grew up in Santa Cruz, went to school in Palo Alto, now lives in San Ramon and has a 100 acres of grapes and 100 acres of almonds on the San Joaquin river just outside of Manteca, I get to spend a lot of time in that area! Great place to live!

 

Interesting result with the new Michelin Pilot AS4 tires. Probably wouldn’t matter what tire. When the old tires were off, I looked at them in more detail. One was getting close to the wear bar (maybe 1 or 2mm). One had a funny dent inside of it, two looked close to new. Over the years I’ve had a couple of new tires put on via wheel rim repair and my wheel warranty policy. So I ended up with a bit of a hodgepodge setup of different tread depths. All Conti Contact Pro tires though, all the same.

michelins go on and immediately notice it’s even quieter in the cabin. We drove the car from Naples to Miami and back yesterday, and glass smooth. Rides great. But got me thinking.

On an AWD vehicle, where one tire is notably lower on tread life to the other on the same axle, wouldn’t that causes some rotational stress on the differential? One having to spin just a little fast than the other due to reduced circumference of the tire? Or is that overthinking it too much.

Eitherway, the new Michelin tires are great. Conti pros were great too, but I personally think the car rides better with the Michelin’s, but clearly a personal preference. Been around enough car forums over the last 20 years to know two things to discuss in great detail that are about as useful as a left handed baseball bat - oil and tires!

 

You are over thinking the tire wear/differential. There always is movement between differential gears. No tire is exactly the same size when driving the car and you seldom drive perfectly straight anyway.

 

Yep, that’s what I was thinking (over thinking).

I just remember hearing back in the day when I had a Subbie Outback that they would not just replace one tire at a time. Had to be in pairs. That was 20 years ago though...

 

Those tire sales people are smart...

After they sell two tires do they also monitor those tires that the air pressure in them us exactly the same...I bet not...

 

Have you ever tried the Continental DWS line? My car has a matching set of the ProContact tires - the OE tires that were replaced by the dealer during CPO - and I dislike them. They're wearing OK and they're OK at everything, but the DWS tires I've used on my past Benz cars are noticeably better in all regards. I expect I'll go with DWS or (discount tire exclusive) SRS tires once these are done. But the AS4 looks interesting.

You're running the staggered setup right?

 

I have the original staggered 18” wheels and 17” non staggered that I currently have under the car with the garbage michelins.

For me the wet grip is the most important quality of the tire. I ran many sets of Nokian summer tires in my cars. The latest one was Nokian zLine UHP summer tires. Had 3 sets of them. This tire had wet grip so good it was difficult to make the traction control light to even blink with my almost 400 hp E550.

Unfortunately they stopped selling the summer tires in our market area and replaced this tire with zLine A/S because vast majority of tires sold around are some sort of all season tire. I don’t think the wet grip of this tire is as goofs as the Summer tire version had.

Further more, they don’t make the 265 width for the 18” rim and my plan is to get new rubber for the original rims. There is a 255 width that I’m thinking to get and I believe the zLine A/S wet grip is superior compared to these Michelin XMX garbage I have.

If I knew some other tire with good wet grip I could go buy it but I’m not willing to buy big name expensive tires and find out they do not have what I’m after, the wet grip.

I went with Nitto 555 G2 because I have Nitto tires under my SUV and I like them. Very decent wet grip and nice soft feel when driving. The grip is superior compared to Michelin’s I have. They have very aggressive looking tread but they are quiet and that tread plows thru water puddles with ease. But it is a summer tire.

 

I just drove 720 miles today with the new Michelin AS4’s - other than a crap balance job that I think three a weight loose somewhere around Jacksonville FL about 5 hours ago, they’re excellent! I like the ride much better than the Conti pro’s that were on there via the same dealer install at CPO. The Michelin’s absorb the road imperfections better without eliminating the sport aspect of the car. If you go with them, regardless if your car needs it or not - get it realigned to the tire. I didn’t. It’s straight as an arrow but think the camber might need to be adjusted a little to compensate for the new tread. I can feel the rear grabbing the pavement a bit more and seems to be fighting the forces a little more than usual.

I also drove through a wicked downpour on Wednesday coming back across from Miami to Naples via I75. It did fine and never once felt the car lift onto the top of the water even at 75mph.

on smooth blacktop, they’re utterly silent. On roughy blacktop, no out of scope road noise. On concrete, nice and quiet and smooth as well. On the Conti’s, you could tell which pavement type you were on, especially concrete. Not so much with the Michelin’s so far.

another 350 miles tomorrow to finish the trip. Then back to the shop for a proper road force balance of the wheels and check the alignment for the new tread. Otherwise, all good! Will park her back in the garage for next time for awhile.

 

Alignments are a crap shoot here for me. Unless I take it to the dealer, the shops around here don't seem to know what they're doing. I don't need new tires for a while, though.

 

Hello, did you get any information about the problem? Was it fixed and what was the solution? I have the same problem with my W212, same humming noise in 6th and 7th gears. First 5 gears are great, no noise no vibration. I need your advices. Thanks

 

I do as well. 14 GLK 350 4matic 32K. Starts when I hit 60+.