DYC300

I'm driving a W205 C300 that's currently under CPO warranty till June 2024.

I wanted to get the opinions of MBworld in regards to the items below.

1. Transmission mount: did a service B at an indy and they said the transmission mount is somewhat worn (engine mounts are fine).
2. Hissing sounds from brake pedal (brake booster?): seems to be a common issue among W205 owners. Hissing sound when applying/releasing the brakes, more prominent when it is cold. Some owners replaced the brake booster via the dealer. Others say, its just normal...
3. Day time running lights (hockey stick looking lights): one side turns on and off faster than the other. Brightness appears OK when fully on, but concern is when the lights are turning off and on. Could be a worn DRL control module? No error codes on dash board but would like to resolve this in case the module fails in the future.

Obviously, the only people that can absolutely answer my questions would be the dealership. But I absolutely despise going to the stealership and spending all day there. To be frank, I don't even have the energy and motivation to fight them at times because of how stubborn they can be.

Gut feeling is that I'm going to have to fight for each of these items to be covered under CPO warranty, pay the diagnostic fee, and wait half a day for an answer. Worst case would be waiting all day, paying the diagnostic fee, and the service advisor telling me "everything is OK."

I welcome any thoughts, suggestions, and ideas on how to tackle these issues.

Thank you!

mercedesmax

Transmission mount wear item not covered
Brake pedal should be covered. I had a customer with the same issue.
DRL, tricky. If there is no code not sure what can be done. You would definitely have to pay the diagnostic fee and see what they say.

DYC300

Thank you for the response Max.

Any insight as to why engine mounts are covered, but transmission mounts are not? (I found a CPO warranty coverage document floating around the internet).

And for the DRL, the issue is so obvious that clearly something is wrong (visual inspection), in my opinion. Question is whether it is covered by warranty? Based on the same warranty coverage document above, all electrical systems should be covered...

mercedesmax

Love to see that documentation. Engine mounts are not covered. Unless you are referring to the active mounts on some AMG's.

DYC300

I'll do you one better... I found the CPO warranty documentation from when I purchased the coverage.

Please see the attached file (removed all my personal information of course).



EDIT: for others looking at this thread

DRLs might be covered under electrical systems?

W205C43PFL

What is the mileage on your car, otherwise it sounds like the transmission mount is wearing a little too fast and too early?

W205C43PFL

I believe transmission mount is also called "rear engine mount" on some MB models.

mercedesmax

Interesting on the engine mounts. It must be that since its a 1-3 year warranty on a relatively new car they will cover them. Eventually the rubber in the mounts will harden, crack and fall out. I see transmission mounts aren't covered.

W205C43PFL

Besides your mechanic saying transmission mount seems to be a little worn, do you notice vibration when idling, or transmission jerking, clunking when shifting or accelerating from a stop? Those are some signs of transmission mount worn for example.

DYC300

Current mileage is 61,000 miles. I was indeed surprised to hear that my mount is worn enough for my indy to tell me.

Okay, this is good to know! Unfortunately, I don't see this as a listed item. Why are motor mounts covered, but not transmission mounts? Or does motor mounts indeed cover engine + transmission?

• I do get some vibrations when idling (only noticeable when cold).
• Transmission always jerks from 2 -> 3, but this is a common "characteristic" of the car apparently (I've researched this thoroughly and gave up trying to fix it).
• Don't recall any clunking lately.

DYC300

Generally speaking, how long should I expect engine and transmission mounts to last before they need replacing?

Might be hard to answer considering factors like time, mileage, type of driving, weather, etc.

mercedesmax

It is hard to answer. My 2015 ML with 55,000 miles needs an engine mount now. Of course, it's very hot here in AZ, so rubber items don't last as long as in other places.

Highline-Autos.com

Transmission and motor mounts are covered by from both of our extended warranty providers, Fidelity and Freedom Warranty. We see them as more of a wear item, but hey, it helps our customers out so we are happy!

W205C43PFL

Hmmm that is a little low to have mounts worn already, do you brake boost or launch the car often, how is the weather like?

For this... I honestly am not sure...

I see, ya these transmission can jerk even when it is normal, no clunking is good, as for vibration do you recall having it a while ago? If you do it was probably normal.

DYC300

To be fair, the mechanic said its a little worn. No urgency to replace them as far as I can tell.

Honestly, when I first got the car @ 42k miles, I would launch a few times here and there. I stopped doing that a few months into ownership and I save the aggressive driving for free way ramps.

Weather is nice and mild SoCal weather.

It could very well be that the vibrations were always there and I just started noticing. It happens...

BTW, I wanted to ask: when my car wakes up from start/stop, I can feel a very prominent shudder that lasts about 2 seconds. I can only feel it when I am idle and the car automatically wakes up or I manually turn off start/stop.

When I accelerate after the car wakes up, I don't feel the shudder at all. I think it's the AC unit because it is usually more prominent when I have the AC at a low temp, so it's working harder.

Do you experience this at all? I'm 100% sure this didn't happen when I first got the car.

W205C43PFL

Hmmm, I don't experience what you have, that said we have a different engine though.