DukeBoy27

After nearly 7 years of ownership and now at 99k miles, the 2012 R350 (gasoline engine) will be going to the dealership for the last annual service while under extended factory warranty. The car drives fine and everything works, but below are some symptoms that I'd like to get your feedback on

1) When coming to stop at a light, sometimes there is a bit of clunking/creaking coming from the front suspension. Maybe the front axle is worn, but want to see if anyone else had this problem
2) The car feels a bit loud at idle... sounds like a diesel? My old 2010 GLK350 has this problem years ago, and at the time the dealer told me that it is just loud lifters. Want to see what you'll think
3) There is a bit of a jolt sometimes under hard acceleration (in comfort mode, so this will be coming out of 2nd gear). Maybe motor/transmission mount going?

Other than these... knock on wood... the R350 has been reliable. I was close to trading it in last year, but felt too emotionally attached to let go. The kids practically grew up in the car and we had so many wonderful memories of road trips. So I've picked up a C55 (from a forum member, go MBWorld!) for daily drive duties, and hoping the R350 can go another 100k miles.

So please let me know if you have any thoughts on these symptoms I have noticed, and any other potential issues I should ask the dealership to check out. Thanks!

Lioninstreet

DukeBoy27, it sounds like you have a nice R!

I got my '12 with 104k on it after what seemed like someone's CPO had just expired. What a great compromise between a van & a SUV. Other than the common MB failure points (airmatic shocks, & a sensor here and there) and the typical mechanical wear items all cars have, it seems pretty bullet proof. I'm planning to hold mine for a while too.

That sounds like ball joints, do you hear the same sound going over speed bumps and when pushing down on the front suspension when the car is parked?

The '12 has a different (new design) gas motor than what they used in the 2010 models. Mine kinda sounds like a diesel at idle as well. I asked my indy about it and he said that's how all the M276's sound. It's prolly nothing to worry about.

Sounds like it's time to find a trustworthy indy who would put it up on a lift and let you know what's really going on. At least with that you'll have a better idea about the condition of the car before heading over to the stealership for that last warranty claim.

Maybe someone else can chime in!

kombifan

So I also get all my repairs done at the dealer because of the extended warranty so I'm a bit knowledgeable when it comes to the difficulty and what they end up do repairing.



The front suspension noise is highly suspect iof the sway bar end links. These go bad very early on and you usually do not notice until you put new ones on all 4 corners and it's a world of difference from before.


The rough idle can be the pcv oil serpeator and cover becoming blocked and sending back unfiltered air bCk to the engine. It's also a known issue for oil leaks.

Definitely could be a trans mount or engine mount. I could only guess

chassis

In addition to ball joints and stabilizer bar links, the suspension noise described may also come from upper shock/strut mounts.

The "diesel noise" may be an exhaust leak beginning to develop. This is likely low probability.

kombifan

P.s. Try the Liqui molly engine flush. And the Liqui molly ceratec and combine it with either castrol edge or the Liqui molly 5w40 and your engine will run like cream.

I use it and it's quited down significantly b

Lioninstreet

You mentioned you don't really notice the sway bar end links are going until they are replaced. What was the symptom that led to their replacement?


Great tip. Are you running the m272 or the m276?

kombifan

M273.


So I had to replace the fronts twice. Rear once.

I did it in Sept 18 and replaced rears with oe lemforder and front reins.
ehe reins failed 2 weeks ago and my extended warranty paid for those; but the dealership couldn't replicate my jntial complaints in Sept which included knocking, and hard feedback through the steering wheel over rough roads and when accelerating.

I would stick with lemforder sway bar end links or mb and also replace the bushing on the front sway bar.

TonyA

I recently picked up an 08 with 95k miles, needed a rack and pinion as well as an axle. Parts came out to ~$600. The rack was a b1tch to replace