Mercedes - why can't they get engine mounts right?

[pezzy669]

So quick back story - just traded my '09 C300 in for an '11 E350 4Matic, yes a huge leap in refinement between the two cars and my new to me E350 is leaps and bounds better than my C300.

But....like my C300 with the same M272 engine the engine mounts and transmission mount in the E350 are shot just like they were in my C. Through research when I had my C and now the E it seems as though Mercedes mounts only last ~80k miles. For an automaker whose slogan is "The Best or Nothing" I find it pretty appalling they can't engineer an engine or transmission mount to last longer than 80k miles. The mounts in my C were not to the point they needed replacement, was only getting a clunk here and there on engine start. The E on the other hand clunks noticeably on cold starts so I am going to need to address them soon, my C300 they were not nearly as bad at the same mileage.

Don't get me wrong MB engineers some fine cars and I will drive nothing but an MB but the crap engine and trans mounts are a sore spot for an otherwise fine automobile. When they go bad it just turns a good car to bad, clunks on starting and vibration at idle. I just don't understand how the self proclaimed worlds finest can get a block of rubber wrong.

 

[dishdude]

Glad I unloaded my 2012 E350 a few years ago! It actually seemed like a solid car so if motor mounts are the only thing you're griping about I wouldn't complain.

 

[pezzy669]

Originally Posted By: dishdude
Glad I unloaded my 2012 E350 a few years ago! It actually seemed like a solid car so if motor mounts are the only thing you're griping about I wouldn't complain.


LOL - I know they can cost some $$$ to keep running just like my C. The W212 (2010+) seems to be pretty reliable for the most part compared to the prior generation. Seems to be the W204 C class (08+) and W212 E Class (10+) were when they finally departed from the dark Chrysler marriage days. You would think with how much $$ they were sucking out of Chrysler their quality would have been top notch but in reality it was complete opposite.

 

[RooflessVW]

I'd go so far to say that no one can really make a decent hydraulic engine mount.

And just because a mount hasn't completely failed at 100k doesn't mean that there would be no benefit from a new set - and that goes for pretty much any car.

 

[CarbonSteel]

Does MB consider them to be wear items?

 

[Olas]

The right engine mount for a luxury car like Mercedes is a cotton candy & chewing gum mount which isolates 100% of the NVH for that luxury feel. Unfortunately something so soft and compliant isn't very tough.

The other end of the spectrum is a Group4 style mount with a small poly insert - excellent at maintaining location under arduous conditions but not so good at NVH isolation.

Every part of the car is a compromise.

 

[Ducked]

Originally Posted By: Olas
The right engine mount for a luxury car like Mercedes is a cotton candy & chewing gum mount which isolates 100% of the NVH for that luxury feel. Unfortunately something so soft and compliant isn't very tough.

The other end of the spectrum is a Group4 style mount with a small poly insert - excellent at maintaining location under arduous conditions but not so good at NVH isolation.

Every part of the car is a compromise.


Re your signature quote, mine cracked, apparently in tension from torque-reaction.

I put cable ties around them to put them in compression. Holding so far.

 

[Trav]

Its not only MB lots of vehicles with hydraulic engine mounts see early failures in comparison to more conventional mounts, that's the price you pay for not "feeling" the engine inside the car. Consider them wear items.

 

[E150GT]

I agree that engine mounts don’t last in a lot of cars. My Mazda. My sisters ford. What really makes me mad is that the aftermarket cannot make a decent mount. They are all terrible.

 

[Olas]

That's just not true. Lots of aftermarket companies manufacture excellent engine mounts. Epytec and powerflex are the first names that spring to mind.

 

[RooflessVW]

Not sure a polyurethane engine mount is well suited to a Mercedes E Class.

 

[Olas]

He didn't say "suited to an E class", he said "decent". There's no arguing that multiple decent aftermarket mounts exist, however your American English is not really English but shares common words. This explains the miscommunication often seen on international forums.

 

[JHZR2]

This isn’t new. W123 and similar era cars went through engine mounts pretty fast too.

 

[Trav]

Originally Posted By: E150GT
I agree that engine mounts don’t last in a lot of cars. My Mazda. My sisters ford. What really makes me mad is that the aftermarket cannot make a decent mount. They are all terrible.


OE style aftermarket mounts are generally very poor quality (and that's being charitable), there are a few for specific makes and models from companies like Corteco that are okay but the application catalog is thin. PU is nothing for a street car unless you like your eyeballs and teeth rattled out.

 

[Johnny2Bad]

Almost certainly its a NVH (Noise, Vibration, Harshness) choice made by M-B. Motor mounts are easily felt in the seat, steering wheel and sometimes shifter. Softer units will last less than stiffer units, but stiffer units transmit more noise and vibration.

So the short answer is as far as M-B is concerned, they probably feel they have the motor mounts exactly right.

No engine mount lasts forever, whether it's use-based or time based (20 years and pretty much every OEM motor mount is in need of replacement). It is a wear item on every vehicle. It's just a matter of how soon and how often.

OEM mounts, with very few exceptions (including most performance models) are synthetic rubber and steel construction. They are the softest, smoothest feeling, and fastest wearing types. You can always replace worn mounts with OEM-style or Genuine OEM replacements, and expect as-new NVH from them. Virtually all aftermarket "performance" polyurethane mounts are harsher than OEM. It's possible to make "soft" PU mounts (the durometer range of PU is wider than synthetic rubbers) but the aftermarket doesn't do it.

 

[Wolf359]

Originally Posted By: rooflessVW
Not sure a polyurethane engine mount is well suited to a Mercedes E Class.


There were some people who got tired of replacing the mounts and used polyurethane instead. Not the same at all like the OEM mounts. It's just the cost of owning an E class.

The only thing I don't like is that there are so many part numbers, Sport vs 4matic can be completely different parts. And EPC (electronic parts catalog) used to be free too, but now it's $75 a year.

 

[edwardh1]

maybe lexus has figured it out.
motor mounts should not be failing

 

[Dino01]

Originally Posted By: edwardh1
maybe lexus has figured it out
to some degree, but while they may be cheaper to maintain, Lexus are nowhere near as smooth or isolating as their MBZ counterparts.

As my CLK is approaching 100k I am also going to replace the mounts

 

[pezzy669]

Thanks everyone for the input - makes sense it is a wear item but figured it would be a 100k+ item, seems to be a 70-80k item on MB vehicles.

Going to bite the bullet and replace with OEM - got some quotes back and to do all 3 is going to be ~$2100. About $1k more than I was anticipating, but apparently on the E350 (or maybe just 4Matic version) the exhaust manifold has to be disconnected and dropped to replace some of the mounts. #rolleyes On the bright side doubt I will have to touch them again before I trade the car in 4-5 years down the road.