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I have a 2018 C300 with 41k miles on it. I'm the second owner and my checked engine light came on while exiting the freeway. I took the car to the dealership and they said that piston 1 need to be replaced for 10k. I said this should be covered under warranty as a defected engine. No luck! MBUSA wouldn't give me a solid answer as to why the repairs wouldn't be covered. The dealer is acting like i'm the bad guy who damaged the car. WHAT! Now I have to deal with my Extended Warranty. I received a call today asking me to authorize the teardown so that my extended warranty can investigate. I'm not authorizing 7k for them to break down my engine. I'm looking into a Lemon Lawyer asap. any feedback?
@MByrd A 2018 with 41k miles should be covered under factory warranty, correct? Why isn't the dealer covering the repair under original factory warranty? The factory warranty is transferrable to subsequent owners.
It should be covered by the factory warranty or extended limited warranty. I believe Mercedes should step up to the plate and give 10 year/100K miles for these engine. It is a shame that a Mercedes engine last only 20-50k miles! MERCEDES BENZ ARE YOU LISTENING? BTW MB dealers have a major attitude problem! My 2016 BMW 535i had a rear engine seal leaking and it was fixed under the extended warranty l bought at the dealership. They called and said l needed to keep the loner for couple more days and that was it. More like going back to BMW after the C300.
Did you purchase your car from MB? If so, bring this up to the dealer manager an see why they won't find it under warrant as this is the engine which is to be warrant up to 4yrs 80K. Where are you?
So sorry for your trouble. Make sure that original warranty is transferable to the 2nd owner and if that's the case then I also think this should be covered under the original MB warranty. I think they're for 4 years and 50,000 miles? Your car is only 3 model years old now. Maybe try another MB dealership in your area? I would also suggest contacting MBUSA about this as well as filing a complaint with NHTSA..
Same problem for me. Own a 2016 C300 at 50K miles, my car started to have check engine light come on, vibrating and shaking, now smoke coming out of the rear. Dealer said warranty expired and nothing they can do. They want to charged $20K to replace the engine. This is crazy.
Same problem for me. Own a 2016 C300 at 50K miles, my car started to have check engine light come on, vibrating and shaking, now smoke coming out of the rear. Dealer said warranty expired and nothing they can do. They want to charged $20K to replace the engine. This is crazy.
This is totally unacceptable. I would suggest you file complaints with NHTSA, and MBUSA. Then I would suggest you contact the consumer affairs reporter at one of your local tv stations and get them involved. It's amazing what can happen when bad publicity for the dealer shines a light on such an issue.
This is totally unacceptable. I would suggest you file complaints with NHTSA, and MBUSA. Then I would suggest you contact the consumer affairs reporter at one of your local tv stations and get them involved. It's amazing what can happen when bad publicity for the dealer shines a light on such an issue.
I reported this to NHTSA but we need more people to report this issue in order for Mercedes to do something about it. I spoke with a local Mercedes specialist repair shop and they said they just did 3 of the same piston#1 problem on C300 this past few weeks. I will be repairing mine at another dealer who gave me more reasonable pricing but it's still north of 10K - Mercedes Benz USA declined to participate with the repair and did not give a reason why. Very frustrating.
Another potential issue is gas leak, if you smell gas inside C300, please replace the gas tube immediately. ( Normally it happen under 10 degree C in the morning ).
Just found out I have a same issue on cylinder 3 ... 2015 C300 4matic with 67k miles on it. Also California car well maintained in pristine condition otherwise. Waiting to hear from the dealership $$$?
First of all, in reading all these posts for the first time, I can see why my 20 and 30 year MB indie techs said "engine problems" when I asked any common issues on these. He also said "change the oil" which I HOPE will help. We also did the plugs at 59k. In 30 years of driving, I have never run any turbo-4 or any car that holds less than ~5 quarts of oil past 5k miles. EVER. Not trying to be funny, but how often do you guys change your oil? Never forget the FSS system of yore, where engines were destroyed by MB marketing trying to say "buy this car and it will only cost you $X in maintenance per year." 10k maintenance intervals on the non-AMG 205 are a JOKE. Please tell me no one here has fallen for it? I change the oil on my M120 V12 with 192k once a year, which is about 5k. And that is a 10.5 quart sump. Not being accusatory, just wondering. These small turbo motors are HEAT MONSTERS. Turbos, spark plugs, pistons? Not taking the chance. Which leads me to...
Originally Posted by Mr. J
Agreed. I think the M274 is already pretty wrung out. Like any other modern FI motor, you can get bigger numbers out of it with more boost, bigger snails, or meth. However, the M274 is not sufficiently "overbuilt" enough from stock to handle all the extra powder.
The first thing I thought when we drove this car was how much power these small DI turbo motors make now.. It's a ton. Want more? Buy am AMG. Why would anyone buy this car and spend $10k to mod? Hello, buy a CPO AMG and sleep better. Else be happy, because in the late 90s and 2000s us Audi/VW people were dealing with 2.0 turbo motors that made 170-225hp. We modded them to get the level of power in the M274. How much power do you want from a 2.0 4cyl? Alloy is alloy, it is not made of saturn-anium and able to defy physics.
Originally Posted by NailsByHoney
Unfortunately that would be a big no. That is what I was told when my car was dropped off again 2 days ago for the same piston issue and I am at 49,900 miles
As far as stock motor failures go, if a warranty doesn't cover a MOTOR, what the hell does it cover? Of COURSE it covers the motor internals. And a lot more. GF is getting her Pano roof replace under CPO warranty due to wind noise. About the only thing not covered would be wear items, and basic body/interior trim and paint. Even the finicky touch screen is covered.
My advice after owning MBs for 20 years is buy CPO, or buy old and restore (as your fun car), else LEASE. Why would anyone pay cash money or take out a loan even at 0% on a new entry-level luxury car? Hello 50% depreciation BEST case after 3-4 years. Specifically why I implored my GF to go look at her C300, which hopefully turns out to be a good decision - but meanwhile, a 16 luxury trim with every option except Distronic and leather, $48k window sticker, $20,300 out the door in June of 2020. And now a $2100 3 year CPO extended warranty that just paid for itself plus probably a grand this week.
The other thing is, does anyone have sales figures on 2015-2020 M274 cars in the US? How many sold? How any failures? Probably less than 1%. Still a design flaw. Buy used and get the CPO extension, buys you time. More importantly, what's the rule that hasn't changed in the 30 years I've been driving? Never buy the first year of a new design.
Last edited by will_w204; Jun 19, 2021 at 02:09 PM.
Oil changes won’t solve piston cracking. Change the oil every day and piston cracking won’t be cured.
Leading theories on root cause for this are:
- bad design or bad manufactured lot of pistons
- tuned too hot by MB, still points to poor piston design
I agree on not buying the first year of production. However this has nothing to do with piston cracking. 2017 and 2018 model year piston failures have been reported on this site. The M274 has been around for a while.
I agree that a bad design is a bad design but, it's also important to note that clearances in modern engines are significantly smaller that the engine clearances for my W201 that was built 30 years ago. Because if this, it's more important than ever to keep up with the regular maintenance and do it at the intervals noted in the owner's manual. Every little bit does help. I'm certainly not saying that lack of maintenance was an issue in any of the cracked piston cases reported in this thread but it's important for owners to do as much as they can to try to keep their car in good working order. Doing so will further help to identify what may well be a design flaw. It would be interesting to know what W205 sales have been when compared to the number of W205s being reported to have the cracked piston. I have no idea what that is.
I agree that a bad design is a bad design but, it's also important to note that clearances in modern engines are significantly smaller that the engine clearances for my W201 that was built 30 years ago. Because if this, it's more important than ever to keep up with the regular maintenance and do it at the intervals noted in the owner's manual. Every little bit does help. I'm certainly not saying that lack of maintenance was an issue in any of the cracked piston cases reported in this thread but it's important for owners to do as much as they can to try to keep their car in good working order. Doing so will further help to identify what may well be a design flaw. It would be interesting to know what W205 sales have been when compared to the number of W205s being reported to have the cracked piston. I have no idea what that is.
Per what Chassis said, I would have thought a bad batch/metal fatigue, but maybe just maybe they are tuned too hot. I wonder what the piston differences are in the AMG 4 cylinder? Isn't that motor putting out over 300hp?
What you said 190, all I know is in a very brief phone call my techs who came from the dealer in the early and late 90s and who have been wrenching ever since said "engine problems" due to people "not changing the oil every 7500 miles" which is the max they are recommending on all their customers' 274s. We are doing 5k; I didn't like the way the oil looked at the 5k mark.
Been following this thread for a while. 2015 C300 production 7/15. Brought in 2018 as cpo with 10k miles and purchased extended 2 year cpo warranty. Car was great until recently it all of sudden idled rough and lost power. 32000 miles.
Dropped off at dealer. They diagnosed cylinder 1 misfire leak down and compression test failed.. Disassembled engine and piston skirt cracked and scorred cylinder wall.. Dealer ordered reman long block from Germany. 2 weeks later picked up car and it runs great. As soon as warranty expires it will be traded in. The extended warranty paid for itself but I can see the potential for this happening again.
I am another consumer that has this engine failure issue due to a cracked piston. I am also very surprised. I always bought Mercedes cars due to quality and rock-solid manufacturing. I am now very nervous. My C-300 is a 2015 model with only 62000 miles and has this issue. I recently saw a recall letter for a low-pressure fuel hose. I am hoping Mercedes decides that they need to stay behind their product on these C300 issues. Did someone initiate a class action lawsuit as mentioned in previous posts?
Thanks
I believe the only C-class shipped to North America from Germany was the wagon. This was a huge factor in my choice to buy. Sedans built in the US seem to have a lot of issues..
Last edited by c-classwagonman; Sep 21, 2021 at 04:30 PM.
E300 piston 1 cracked now misfiring and compression loss with 55k miles. Cyl scoring, engine replacement with possible turbo and cat replace $18k estimate from the dealer. MBUSA has been kind to make a lengthy review, a month, finally decided to offer $0 assistance for the repair, the dealer has advised they can offer a 10% rebate. I'm insulted
I had heard that piston slap too, I thought it was the injectors. GLC doesn't, but I feel it's a driving time bomb.
I didn't realize the numbers of w205s with this problem too.
A class action suit involving the M274 aluminum high compression engine's piston design would certainly have broad appeal.
E300 piston 1 cracked now misfiring and compression loss with 55k miles. Cyl scoring, engine replacement with possible turbo and cat replace $18k estimate from the dealer. MBUSA has been kind to make a lengthy review, a month, finally decided to offer $0 assistance for the repair, the dealer has advised they can offer a 10% rebate. I'm insulted
I had heard that piston slap too, I thought it was the injectors. GLC doesn't, but I feel it's a driving time bomb.
I didn't realize the numbers of w205s with this problem too.
A class action suit involving the M274 aluminum high compression engine's piston design would certainly have broad appeal.
Maybe you should contact your local branch of the Better Business Bureau and also a "consumer affairs" reporter at one of your local tv stations to shine a light on this issue. It's amazing what wonders bad publicity can do to resolve an issue satisfactorily for the consumer.
Started having the same issues that ended up getting my first engine replaced now with the second engine. This engine is seriously a POS. Got it running ok and immediately sold the car back. I’d be very surprised if there isn’t some class action suit. Engine was from 2018.
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