slb7269

Hi all and thank you in advance to any advice and insight.

Bought this car back in 2019 as a CPO vehicle with less than 30k miles. As a CPO it came with an extra year warranty, and I bought an extra 2 years of extended warranty which ended this past December.

It now has 56,000 miles. My wife and I noticed a couple misfires recently when driving the vehicle. Last week I was driving on the highway, and as I got up to 65MPH, the engine light flashed, and the car started shaking and rattling so I went and took the exit. Was stopped at a light, turned it off and back on, and drove at low speeds to a local food store lot. I was close to home so I drove it back at a low speed.

I have a family friend who used to own a dealership and used a code reader and it came up at #4 cylinder and we replaced the coil pack and spark plug. Since then car is running OK, but I already had a previous appointment at Mercedes that was coming up. That appointment was this morning.

After test driving the car, they said the engine light came on again. Upon further inspection into the cylinder, they used the scope and saw "a ton of oil" on top of the piston. They switched the OEM #3 coil pack with the after market one which was in #4. They said the light did not come back on but that if it does, then I need a new motor. I then asked, what is another reason that I would have oil in the cylinder on top of the piston? He responded well.. if there's oil in the piston, then there is either a crack in the head of the piston or a failing seal, in which would require a motor replacement.

I told him why wait? We are just waiting on the inevitable to happen.. lets get this process started now.

So.. now I am waiting to hear back and hoping Mercedes can help with this considering my warranty ended less than 6 months ago.. so I am here to ask... am I ***** out of luck??

S70Houston

Sorry to hear about your misfortune and very sorry to be the bearer of bad news, but it is very doubtful that MB is going to do anything if your warranty expired.

However, I would definitely try and push as hard as I could, but don't get your hopes up too high. Sorry.

Furthermore, I would get a second opinion from a good and reputable Independant shop specializing in Mercedes. I have had NOTHING but bad experience with the dealership here in the last years and will not go unless I have to (Recall), as I believe they are useless, not very knowledgeable and of course want to sell you an engine replacement so they can make top dollar.

Good Luck, keep us posted.

chassis

Sorry to hear about the experience.

Sadly this is the latest of a long list of owners who have experienced the same thing: MB junk. More specifically, the M274 engine (junk) which is known for cracking pistons, among other sordid failure modes.

Do not buy any MB four cylinder: M274, M264, M254, and their affiliated variants across several vehicle platforms. Most notably X253 GLC and W205 C-Class, plus others.

There are several active threads in the GLC and W205 C-Class sections of this site. Agree with the above that financial assistance from MB will be either zero or a de minimis discount on a new car.

W205C43PFL

Interesting it came back from cylinder #4 this time, the usual piston cracks in the M274 from what I read are from cylinder #1, I wonder if there is more to this...

slb7269

when you say you wonder there is more to this, what do you mean? I am no car expert so just curious

W205C43PFL

Firstly, did you get a second opinion from another shop? The cracks usually happens on cylinder #1, so your case is the first I seen if true on cylinder #4.

mikapen

Change dealerships before condemning all of them.

Regarding Indy's if you know of a good one, their second opinion might give insight, that might provide useful diagnostics.

Probably not a free engine, though.

slb7269

So... the dealership I was working with reached out to Mercedes to see what they can assist with.

Mercedes came back and said that they are "willing" to cover 50% of the necessary parts. The labor and other half of the parts would be my responsibility..

Can't say I was expecting anything, but I am extremely disappointed. I have not gotten the official quote yet.. so no idea how much we are even looking at.

chassis

It is a bummer that anyone has to experience this. Sadly it is an example of MB junk. There are too many additional examples to list.

On the other hand, the offer you received for 50% of parts compensation is the most generous posted to this site so far. Maybe MB is finally feeling guilty enough they are opening their wallets a bit for this issue.

S70Houston

As I had mentioned. Be glad they are willing to cover 50% of the cost.

W205C43PFL

Oh well, I guess 50% is better than nothing, hopefully the invoice doesn't get too high.

W205C43PFL

Damn right.

mikapen

I believe it's only the second one we've seen, and the offer was identical.
In both cases, I don't think we know the service history.

W205C43PFL

Interesting thanks for this information, I guess I missed it, was the other 50% discount case posted by a forum member here? If so any chance you still have the link to that thread?

mikapen

Yes, it was here. I don't have a link, but it was on the 253 forum. I'll try a search later.

W205C43PFL

I see, thanks too, I will try the search as well too if only the search feature was not a pain in the a* to use, will still try.

S70Houston

And what info are you trying to gather, how does it help to know that MB gave 50% for 2
forum members?

Sorry, just trying to understand as I do not get the point.

W205C43PFL

Another forum member mentioned they read a post in the X253 sub forum that MBUSA offered 50% of the repair costs to get their car fixed.

I guess you are right, there isn't really a point of doing so.