I found this great article: http://repairpal.com/cars/mercedes-benz/e350


Brakes

• This vehicle has sensotronic brake control (SBC). If the SBC light on the dash illuminates, have the brakes checked. If the SBC is not working, limited brake pressure is delivered to the front brakes, increasing the distance it takes to stop. The SBC hydraulic unit has a specific service life programmed into the control module; follow the manufacturer's recommended service procedure for proper maintenance of the SBC.
• Follow the two-year service interval for brake fluid flush.

Engine

• The camshaft adjuster solenoid (which is related to the variable valve timing) tends to fail.
• The crankshaft position sensors tend to fail.

Suspension & Steering

• Irregular and premature tire wear can be caused by the front thrust link bushings cracking and causing excessive movement in the suspension. The thrust link bushings are fluid-filled (to help reduce vibration), so if they crack, they will leak oil.
• Due to sticking relays, airmatic pump motors can fail, which causes the pump motor to constantly run. Because of the battery drain this causes, the pump will eventually fail or the battery will go dead when the car is shut off. Worn airmatic pump mount bushings can causes noises in the front axle while driving on bumpy roads or a buzzing noise.
• Rear air springs (bellows) may develop leaks, which causes the air pump to run more often to maintain ride height.

Drive Train

• A vibration felt through the center floor of the vehicle can be caused by driveshaft flex discs, which crack and shred, causing excessive driveshaft movement. Not repairing these can cause damage to the driveshaft center support bearing, or, in the worst case scenario, damage to the transmission or differential.
• High mileage or older vehicles develop leaks at the differential seals and cover; the whole unit needs to be resealed to repair the leaks.
• The 7-speed automatic transmissions can have problems with internal component failure that cause rough shifting going up from first to second gear and going down from third to second or second to first gear. Mercedes released updated parts; the transmission will need to be removed and disassembled.

Electrical & Lights

• Brake light switch failure can cause the ESP and BAS warnings to illuminate.
• The early versions of the central gateway module (which allows different systems to communicate with each other) have software problems.
• Lack of audio or cell phone functionality may be related to the failure of the audio gateway module.
• Water can damage the weight sensor in the front, passenger seat, causing the SRS (airbag) light to illuminate. There is an electrical component in the seat cushion susceptible to fluid damage, so dry up any liquid spills immediately.
• Many software updates are available for the different computer systems, but if the vehicle is out of warranty, it may cost money to receive the updates (unless it is a recall). Some updates may be dealer-only, but a well-equipped independent shop can usually provide updates as well.

Heating & Air Conditioning
A failed digital heater control valve can cause a lack of heat output from the climate control system.


Brakes
This vehicle has sensotronic brake control (SBC). If the SBC light on the dash illuminates, have the brakes checked. If the SBC is not working, limited brake pressure is delivered to the front brakes, increasing the distance it takes to stop. The SBC hydraulic unit has a specific service life programmed into the control module; follow the manufacturer's recommended service procedure for proper maintenance of the SBC.
Follow the two-year service interval for brake fluid flush.

Engine
The camshaft adjuster solenoid (which is related to the variable valve timing) tends to fail.
The crankshaft position sensors tend to fail.

Suspension & Steering
Irregular and premature tire wear can be caused by the front thrust link bushings cracking and causing excessive movement in the suspension. The thrust link bushings are fluid-filled (to help reduce vibration), so if they crack, they will leak oil.
Due to sticking relays, airmatic pump motors can fail, which causes the pump motor to constantly run. Because of the battery drain this causes, the pump will eventually fail or the battery will go dead when the car is shut off. Worn airmatic pump mount bushings can causes noises in the front axle while driving on bumpy roads or a buzzing noise.
Rear air springs (bellows) may develop leaks, which causes the air pump to run more often to maintain ride height.

Drive Train
A vibration felt through the center floor of the vehicle can be caused by driveshaft flex discs, which crack and shred, causing excessive driveshaft movement. Not repairing these can cause damage to the driveshaft center support bearing, or, in the worst case scenario, damage to the transmission or differential.
High mileage or older vehicles develop leaks at the differential seals and cover; the whole unit needs to be resealed to repair the leaks.
The 7-speed automatic transmissions can have problems with internal component failure that cause rough shifting going up from first to second gear and going down from third to second or second to first gear. Mercedes released updated parts; the transmission will need to be removed and disassembled.

Electrical & Lights
Brake light switch failure can cause the ESP and BAS warnings to illuminate.
The early versions of the central gateway module (which allows different systems to communicate with each other) have software problems.
Lack of audio or cell phone functionality may be related to the failure of the audio gateway module.
Water can damage the weight sensor in the front, passenger seat, causing the SRS (airbag) light to illuminate. There is an electrical component in the seat cushion susceptible to fluid damage, so dry up any liquid spills immediately.
Many software updates are available for the different computer systems, but if the vehicle is out of warranty, it may cost money to receive the updates (unless it is a recall). Some updates may be dealer-only, but a well-equipped independent shop can usually provide updates as well.

Heating & Air Conditioning
A failed digital heater control valve can cause a lack of heat output from the climate control system.

 

Thanks for the info

 

I've been wondering for a while now, why my suspension doesn't give that 'Tennis Ball' feel ... My rear does but the front with speeds under 45 mph acts very rattly-like (doesnt Rattle though) .. It does improve at high speeds

Is there any bush or rubber part I could swap to improve front ride quality ?

 

Glad I just purchased the extended warranty! LOL

 

Each issue listed should state it applies to W211 all year/models or be linked to a specific year and model, e.g., 2006 E350 and/or E550. Just summarizing them without this information makes us think they apply to all years/models since the W211 was first introduced, such as my 2003 E500. Some maintenance/repair issues are corrected in subsequent model years, or repairs/software corrections are issued through TSBs from MBUSA that are applied free when you take your vehicle in for regular service.........they are supposed to check whether your vehicle has all the latest TSBs installed even if you're out of warranty. For example, a TSB replaced my SBC in 2006 and a software updated fixed the minor problem with radio/CD system. And I've had my share of failures that were fixed through my CPO Extended Warranty, such as the heater control valve last July and the radiator - transmission problem at 39.5k miles in 2007. But most of the problems you listed have not occurred in my 2003 E500 that's almost 7 years old with 76.5k miles, including the air shocks problem listed. There are some overall reliability issues for such an expensive and complex machine, but I hear BMW has some too. I continue to love driving mine, its appearance and road handling abilities, or I'd dump it.

 

well my friend, its a good idea to keep an eye on these issues - like every make/model, reliability improves year over year - thts why SBC was taken out in 07s & later etc etc

I'm glad you like ur car - almost every major thing has already happened now

\just kidding, enjoy it - thats why every one of us is here on this forum!

 

I'll add a few more minor items that tend to fail from what I have gathered.

Interior:

1. Glove box loses shock absorption and slams open. There is a cheapo plastic piece that holds the glove box to the shock absorber that breaks.

2. Chrome tends to peel on air vents.

 

Same here...good thing I signed up for the extended warranty until Oct 2013....knock on wood.

 

Based on my 2003 Experience you will be glad you did.

Other items left our are

door locks, ignition switch, hot water heater control valve, air springs, a/c blower motors.

Now wonder why I am considering other brands as well as MB. The E350 for 08-10 needs to be reallllllllllllllly reliable for me to buy another.

 

So whats the best year to get? which years didnt come with SBC etc?

 

No SBC on 07s and newer.

My '07 has been problem free.

 

What I thought was the SBC on my 07 happened to be the ABS pump; just as well I disengaged the device prior to replacing brake pads with Akebonos since forcing fluid back without bleeding (like I did when compressing the pistons) can damage the ABS pump, an $1800 item.

 

Yeah so just as a warning I have a 2004 E320 and my crankshaft position sensor went and it was $500 at ~ 60,000 miles.

And I am at 69,xxx miles and that exact thing happened to my climate control too, RIGHT NOW! It won't give off any kind of heat, just cold or AC. Damn, anyone experienced this one and know a quick fix or DIY sensor swap, or just take it to the dealer?

 

After 5 years of ownership I have experienced none of the listed items or any others for that matter on my 05 E320 4M. Its been an excellent vehicle. My take on the list is that many of the items are applicable to most any type of vehicle and many are items are those that result from improper maintenence or lack of maintainence.

 

generally, 05s were a lot better off compared to 04s, and the 04s were better than the 03s.

 

...yor comparison should not be with BMW, who, as you say, is no beacon of reliability, either. It should be with Lexus and Infiniti...and maybe even Hyundai, with their new up-market models that may become a new brand.

Things may start to get very interesting for BMW, in particular, as Lexus appears to be getting serious about the "sport" part of "sport sedan". The new LS sport package is getting very good reviews in the car buff books. We shall see.

- nopcbs

 

This is the second or third time I have read that the SBC unit has a "counter" integrated and that upon reaching some number, it throws a failure code. I would be interested to know what that number is and how to monitor it. $2k is a pretty serious repair bill ticking like a bomb. I have seen an offer from the UK to "rebuild" the pump with an exchange allowance.
Might be like the alternator rebuilds I have suffered in the past, three new diodes and a coat of black spray paint:

 

Your hot water valve has failed. There are detail repair instructions on this site on w211, Take a look and it will tell you how to make the repair.

I am considering repairing my E500 by replacing it with A GS 350 or 300S

 

Give us a writeup on the gs350 when you given it a test drive. I am considering getting one for the wife

 

I dont know if this would be helpful, 2003 and up W211 cars had a issue with SBC unit and dealer should replace it for free of cost. Some dealers will try to make you pay like they tried with me, but be aware of this if your having an issue with your SBC unit.

 

Great thread, I'm going to check my driveshaft...72k miles time to do so.

 

Gone through two blower motors and regulators in two years!