AMGAffalterbach

Hello All,

As many of you know by now my 2007 E550 4Matic has been running quite well for the few months of ownership I have been lucky to possess thus far - however I have a question regarding the M273 engine and it's motor mounts, basically how it should feel on startup.

Let me start by saying I don't believe anything is wrong with the vehicle as it has been religiously serviced since mile 1 from both previous owners but parts just may be getting a bit older. I recently brought the vehicle in on an unrelated maintenance action and everything checked out as being fine.

Anyway my question is this: on startup, cold start or warm start, there is a lot of noticeable torque when I turn the key and the engine starts - not so much that it causes vibration, noise, or anything "bad" "annoying" or "destructive" - but it is noticeable that it exerts force on the frame of the vehicle. Not that it is a problem but I am not too sure how much it is designed to come through to the cabin. It is really the only time I notice this however because under heavy acceleration or normal acceleration it is not an issue, but I want to know if this could indicate any upcoming issues with motor mounts...

Anyone who has an E550 experience what I am talking about? Or is this not normal .

edwinwalke

Motor mounts should not be a problem until you get past 75K miles -- It could go 150K before needing replacement and I am sure depends on your driving style and the engine's torque.

You can check by feeling the engine at idle and at the same time see how much vibration is being transmitted to the chassis. With my E320 CDI you can feel the vibration with you hand on the engine cover and then feel the chassis in the engine compartment and there is little to no vibration. Mine were replaced at 90K and you could feel the vibration in the chassis with your hand and also when accelerating especially when turning.

Barry45RPM

The dealer replaced my Motor/trans mounts on my 07 E550 at about 45,000 miles under extended warranty during a Crank Position sensor replacement service.

AMGAffalterbach

I will look into the service records in more detail to see when that service was done, because I am past the 75,000 mile mark but nowhere near the 150,000 mile mark - the dealership has been good about telling me what is not necessary to replace at this point so I will ask next time I am in.

When the engine is on I do not feel a lot of vibration at idle - not at speed, while turning, or any of the aforesaid but more on startup I don't know if the motor mounts feel as "firm" as they should be so thanks for bringing light to when you replaced your parts so I can research this a bit more.

gaazmon

same here. and after 95k they are gone again had the trans mount replaced at about 80k

i would take that with a grain of salt what they say. the motor mounts are horrible on these cars from what i've read (and experienced)

vettdvr

To quote Alfafa on the "lill'e rascles".. Me too !

My mounts failed about 85,000 The only car I ever broke mounts on was my 64 corvette after a full throttle burn out. Then they were replaced with safety mounts and never failed again. But for MB to be failing this often,, ???

gaazmon

ridiculous indeed. our 02 CL500 has never had the mounts fail (motor nor tranny and it's over 80k miles now... knock on wood)

LAS_Bluetec

Motor mounts break. It's that simple. Replaced them on mine at 55k. They are just rubber filled with hydraulic fluid. The rubber deteriorates over time and breaks. I have not owned a car yet, German or American that did not need motor mounts. Most cars that are a few years old need them, people just don't realize it. At 55k, mine were trashed, and I am not a hot rod driver, its just what happens. It made a huge difference. I do live in a hot dry place so that does not help. The rubber dry rots a lot faster. Mercedes has updated the mounts on the W211's with a new design that should last longer.

AMGAffalterbach

Did not know it was that problematic O_o but I guess in any circumstance part of the normal lifecycle of a car
.

gaazmon

my opinion is they are not designed well (just do a search and see how much of a common problem it is). i've had only one car with them fail besides this one and it was a 94 S420 at about $150K miles (and only once).

just another thing that was designed bad on this car (suspension components such as ball joints and control arms, airmatic system, SBC system, "glycol contamination" issue, fuel system leaking, etc etc)

Zaphodsplanet

I'm on my 7th benz ... I think. Anyway, I usually get about 80K miles or so out of a set of Motor mounts. When they really start to fail you'll know it. The dealer will be the first to tell you when they don't actually feel bad. They'll say they're leaking and you'll tell them to **** off and you're not giving them another grand to change them (like me). BTW.... I still think them telling me that was a total lie. The shot mounts didn't have any oil on them... they were dry. I read somewhere they're actually full of nitrogen. So they're basically big rubber bladders with gas inside. Anyway, you'll drive the car another 30K+ miles or so and slowly you'll start to notice a vibration when you come to a stop. If you wait way too long like I did....LOL.... you'll begin to think you're driving a big mac truck or something. I just changed mine a month or so ago with 115K miles on the clock. They were shot something fierce. I think the engine actually sits at least 2 inches higher in the engine compartment. If you get side tracked after you buy the motor mounts and don't change them because you strip out a bolt on the bottom of the car which would allow you to drop the exhaust system so you can actually gain access to said motor mounts you'll notice a couple other weird noises start to develop. (don't ask me how I know this ...LOL). Main symptom is that you'll start noticing massive vibration when you come to a stop, especially when the car is on the cold side or you're just beginning your first drive of the day.

The cool thing about getting side tracked so many times before actually changing them out is that when I finally did....(took me freaking 7 hours) it felt like I had a totally new benz.

AMGAffalterbach

Nice! Well my car hasn't experience any of those issues whatsoever, so I think I am good for now but I will certainly look into it. Thanks for all the information!

PHDZINE

Mine went out at 60K. Felt like the car had a miss and felt the vibration through out the chassis. IF you raise your car up on a lift, you will see fluid dripping from the mounts if the mounts are blown.

06E5004ME

Mine failed at 142k... both of them. Apparently, two bolts on the bottom (the ones that secure the engine and the mount to the frame) rusted through and a hard acceleration finished the job. Almost took out the driver side axle because of the rotation of the engine. Will be replacing both of them. Pics of the failed ones are to follow soon.

vettdvr

Me too Neither. Just one of the long list of what could have been better.

Glycol cont issue,
Fuel tank leak
Ball joints failing
SBC
airmatic

and on and on and on............

06E5004ME

Pics of the old and new mounts:





As you can see in the second picture, that is where the bolt secures the mount with the engine to the frame. On the old one, part of the bolt is still inside the mount. Other than that, took probably an hour to replace the mounts. Jack up the engine a little bit, undo 2 bolts (one top, one bottom). There is plenty of space to take out the old mounts and put new ones in.

AMGAffalterbach

Good to know that it's something I could *potentially* do myself, however after having spent a few more months with my car I've become used to its feel and how it drives, so as far as mounts go I'm fine for now. Definitely will be using this as a reference though.