My ML's motor got noisy off late..



Started right away without any hicups...and I drove it off....in a minute or so...I felt something different about the motor noise....as I give gas to the motor...it almost sounds like a steam engine reving up....I brought it to a stop and let it idle...the idle noise has changed too...with a mild synchronus put putting sound coming off the exhaust...unlike the smooth running sound of the motor..
I called up the service center and am taking it for a checkup tomorrow...in the mean time does anyone have any insight into this?
The temperatures are also kind of low here at this time of the year...but not lower than 30-35 degrees...



How common is catalytic converter failure on the ML??



I did some research on the CATs and it seems there are tonnes of aftermarket vendors for these..
What's the general advice...stick with MB or are aftermarket ones equally good?
From the noise pattern, mine seems to be the driver side one too...that needs replacement..
I am taking it for a full inspection today to the MB..so will post the outcome in day...



The federal Clean Air Act requires vehicle makers to provide two emissions-related warranties -- a production warranty and a performance warranty. The production warranty requires the vehicle maker to warrant that the vehicle is designed, built and equipped so that it conforms with emissions requirements at the time of sale. The performance warranty requires the vehicle maker to warrant that the vehicle will comply with applicable emissions requirements as tested under state vehicle emissions inspection programs for the warranty periods specified in the law (for model year 1995 and later vehicles, the warranty is 2 years/24,000 miles for all emissions-related parts and 8 years/80,000 miles for the catalytic converter, electronic emissions control unit and on-board diagnostic device). The performance warranty is conditioned on the vehicle being properly maintained and operated.
Like the Magnuson-Moss Act, vehicle manufacturers may not refuse warranty repairs under the Clean Air Acts performance and defect warranties merely because aftermarket parts have been installed on the vehicle. The only circumstance under which the vehicle manufacturer can void the emissions warranties is if an aftermarket part is responsible for (causes) the warranty claim.
I had an MB technician hear my motor...and he feels its definitely the catalytic converter that needs to be replaced...
How common is catalytic converter failure on the ML??



Seems like this is a real shoddy quality vehicle after all...at 70,000 miles I already have a list of major components to watch for..post warranty
1. Harmonic Balancer
2. Motor Mounts
3. Catalytic converter
4. Auxillary fan wiring/harness
5. ESP Lateral stability sensor
This excludes a list of about 10 more things that they replaced under warranty...
1. Skyview roof
2. ESP Lateral stability sensor
3. Fuel injection system
4. Window switches
5. Radio wiring and antenna
6. Steering hose/clamp
7. Fuel injection system
8. ...
9. ...
10. ... I can't even remember all of them...
Now, I am really wondering...is this vehicle worth keeping after all? I had plans of keeping this for 10 years....its not even 5 years yet...and this list is just growing...
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Seems like this is a real shoddy quality vehicle after all...at 70,000 miles.
Now, I am really wondering...is this vehicle worth keeping after all? I had plans of keeping this for 10 years....its not even 5 years yet...and this list is just growing...
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Someone pointed out that one of the several causes for the CATs to fail on the ML is flattened motor mounts.
I was hinted thru my previous service that my motor mounts had flattened a bit. Now, what's the advice, should I get them replaced as preventive maintenence along with the CAT? (Of course I will be paying for the motor mounts...they won't cover those)
How likely is it for the CAT(s) to fail again because of the flattened motor mounts? My guess is that although they have flattened only a bit now...they will get worse by the day....and that would be like risking the newer CAT(s) further.



Both CATs are bad...$700 for the passenger side one and $1600 for the driver side one..both are cracked at the weld...
$400 for the motor mounts...
Fortunately, MB will cover the CATs since I am under 8 yrs./80,000 miles. I am just saved of having to spend a fortune on fixing this one....
But, I still pay for the motor mounts...
ML God...you there??? you are an MB Tech...what's your honest advice...keep this truck...or should I start looking for another one....
Owning the ML is really starting to look scary now...
I also see after market motor mounts selling for $30-60 a piece...some even claim better performance (polyeurethane ones) than the stock rubber ones...what's the general advice, stick with MB, or go after market...I am sure, I can get them replaced for about $250 after market..instead of the $400 at the dealership...
Last edited by mihir_d; Jan 20, 2004 at 09:43 PM.
Here's the final verdict...
Both CATs are bad...$700 for the passenger side one and $1600 for the driver side one..both are cracked at the weld...
$400 for the motor mounts...
Fortunately, MB will cover the CATs since I am under 8 yrs./80,000 miles. I am just saved of having to spend a fortune on fixing this one....
But, I still pay for the motor mounts...
ML God...you there??? you are an MB Tech...what's your honest advice...keep this truck...or should I start looking for another one....
Owning the ML is really starting to look scary now...
I also see after market motor mounts selling for $30-60 a piece...some even claim better performance (polyeurethane ones) than the stock rubber ones...what's the general advice, stick with MB, or go after market...I am sure, I can get them replaced for about $250 after market..instead of the $400 at the dealership...



I bought it with full intentions of making it a once in a life vehicle..something that I would keep forever...at least until 2010...
I still can't deny how thrilled I am with its ride quality and performance...but can't help being worried about its reliability..
I am already warned about the harmonic balancer, something to watch for in 2005.
Its still the beginning of 2004 and I already have 2 problems lined up to be fixed.
1. CATs
2. Motor mounts
In 2003, the highlights were
1. ESP Lateral stability sensor
2. Auxilary fan wiring/harness/fuse
In 2002, the highlights were
1. Skyview roof
2. Window switches/MCS Radiio wiring/antenna
In 2001, the highlights were
1. ESP lateral stability sensor
2. Fuel injection system
plus all the little trim pieces that they have kept replacing through the years...
I only wish MB had made this a lot more reliable than this..



