The engine on my 2017 c300 coupe 55k miles misfired and it cracked the front piston and damaged the cylinder wall. The dealership told me since i'm out of warranty i would have to forfeit $18k to replace the engine. I'm planning to touch base with the corporate help line to see if they can help mitigate some of the loss, but is there anything else I can do to reduce the cost of my misfortune?

 

i would try to find an engine at a salvage yard and not have the stealership do the job.

 

You posted in the W204 section while your car is a W205. Just so you know. Maybe drivers in the W205 are more familiar with this failure and can help you better.

 

My number one reason I would not buy a mercedes again is the durablity issues with their EU-Engines.

In your case replacing the engine is one thing, but it realy expensive seeing the cause was not found, and that may lurk in stuff around the engine, so are you prepared to replace it once more as well-?

 

The W205 M274 equipped cars are really well known for these cracked pistons. The predecessor engine, the M271, was known for timing chain failures. Not sure why Benz has such a hard time with I4 durability.

 

Sorry to hear about the engine problems. Would you be willing to post your VIN? It helps others to try to find a "clean point" if one exists, where the failures are less likely.

 

Buy one online that was lightly used and have a local mechanic replace it. Usually the mechanics will source it for you. You should only need the block, not turbos and ecu's etc. As that will transfer over.

Probably 3-5k job I'd imagine but idk never done it

 

From the looks of the 205 forum, no clean point is going to exist with the M274. This engine was dropped for the M264 for 2019 and time will tell on those, I guess.

 

Hi used engine best option at this stage otherwise 1 new piston and have the bore honed to remove damage and install the piston.
Sounds like have to run these engines on highest available octane fuel to avoid detonation and piston ring land damage.

 

Well said. I hear nothing but horror stories about the M271 engines as the miles start to rack up. I'll never get near one. They are cursed!

 

I mean yeah, these aren't cars where premium is "suggested" it's more or less a requirement. It's not like people here don't run the cheaper fuels but every once in a while we will get someone on the forums with problems and then find out they're putting 87 in, and when they switch back over the car works a lot smoother. It's not really rocket science, this conversation can turn into a whole argument of course and I won't entertain it - but putting less than premium fuel in a premium car isn't gonna cut it. When a 2.0t kia requires premium, you're not gonna put regular in a 2.0t mercedes. If you can't afford the gas, then find something else (not saying to you, but in general)

 

vin number# WDDWJ4JB9HF375303

 

Thanks @Jaron Hu this helps others with due diligence when considering purchasing a vehicle with this model engine.

 

Took a while (3 months) but MB finally agreed to repair their 2018 M274 C300 engine (Cylinder 1 failure at 13,000 km) at their expense approx. 12 hrs after I called head office in Germany and after ghosting my local dealership in Australia for weeks on end. Fortunately I did not need a car. Note, I never received a reply from Germany.



Shortly after agreeing to repair my car they advised they needed to replace the engine (also at their expense). A courtesy car was included the same day as they began their works (2 months). Not a sorry or anything of the kind when I picked it up, it did not even get the standard car wash.



What now annoys me is that what I thought was a "New Engine" is in fact just a "Long Block (in which the entire crank assembly including the cylinder head, valves, injection and much more have been completely overhauled and installed using only MB Genuine Parts), compared to a New Engine or New Basic Engine or Basic Engine or Long Block Plus. In short Long Block replacements are a “remanufactured engine” that does not get tested on the manufactures test stand before been sent to the dealership. You can learn more about that at b2bconnect.mercedes-benz.com/gb/products/remanufactured-parts/cars/engines/basic-engine



Even more annoying is that the this Long Block from the "new engine number” 454,306 provided appears to have been produced 86,479 before my failed engine “540,758" OR approx. 47,704 after MB modified their faulty wrist pins that were installed as of engines in 2015 engine number 274 920 30 406 602 on which leads me to believe this engine may have been produced in 2016-2017 ?? As well as the wrist pin issue, I feel its just MB pistons are sub-par mass manufactured rubbish. They have to have a flaw in them too ? Maybe the M274 just needs some aftermarket forged pistons.



Someone please correct me if my understanding about the engine number is incorrect.



Anyway its now been 5 months and with 2,002 km on the engine and is already more noisey on cold starts that the original engine. Transmission also notably louder. I don’t know what to do, I just know I don’t trust this engine, or MB and I will never buy another MB again. Is it all in my head or should I flick it.



If you are interested in what a new m274 long block sounds like with 2,002 km you can download my videos at recorded on a iPhone 101a M274 2018 Cold Start 3m 30sec - 37-40 deg celsius.mov
https://www.icloud.com/iclouddrive/0...40_deg_celsius

1b M274 2018 Cold Start 35 secs - Bottom Engine Bay + SLOWMO.zip
https://www.icloud.com/iclouddrive/0...e_Bay_+_SLOWMO

1c M274 2018 Cold Start 10 secs at 50 70 80 95 96 deg celsius 4-10.zip
https://www.icloud.com/iclouddrive/0...g_celsius_4-10

No warranty was offered on the new long block as it was done under warranty.MB also returned it with a broken PVC line (crank case vent line) and a torn aftermarket pod air filter. Fortunately as soon as I drove it the 2k drive home I inspected their workmanship. Had I not caught this vent line it would not have been too long before I was back for another engine replacement.

 

Sell it asap, why deal with the headache