When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Wish I would have seen this thread before purchasing my car.
Confirmed 2018 c300. Cracked piston 1 at 43,xxx mls
Covered under warranty. Replacing piston. Will update when I talk to the dealer.
This is the first time I've seen a 2018 report this.. I would have figured they'd have this worked out by that point. We have a 2020 C300 loaner right now and we really like it, but damn.. what is it with Benz and four cylinders? It's like early 2000s Honda trying to build an automatic transmission.
Wait, what? Aren't pistons, piston rings, etc considered "internally lubricated parts" which "all" are noted as being covered in the CPO Limited Warranty?
That is what I thought to until the service advisor said that its a good thing this happened before the 50,000 mile warranty was up because it wouldn't be covered after that. WTF
That is what I thought to until the service advisor said that its a good thing this happened before the 50,000 mile warranty was up because it wouldn't be covered after that. WTF
Pretty sure your service advisor is mistaken. Pistons are lubricated engine parts. It's covered.
Pretty sure your service advisor is mistaken. Pistons are lubricated engine parts. It's covered.
I'm starting to think these mercedes service employees from all the mercedes dealerships need to all be on the same page regarding repairs and warranty. I have heard 3 different stories of what was supposed to happen to my vehicle after piston #1 broke. And now my cpo warranty, trying to figure out whats covered and whats not covered. This has been a complete inconvenience and unneeded stress.
My 2017 C300 started Jerking and lost power and had a ton of white smoke coming out the exhaust last weekend as I was getting on the freeway. Had it towed to Mercedes and this is what they said ---
☆"Hey Honey, so looks like your probably going to need a new engine!! Still confirming but looks like one of the pistons cracked. You're under warranty so its totally covered"
Then today I get this message---
"Hey Honey just wanted to give you an update. It turns out they don't have to replace the whole engine. They are replacing the turbocharger and they have to replace one of the the pistons"
My Response,--. To be honest I do not feel confident in that repair. What kind of warranty is Mercedes willing to put on the engine once the repair is performed. There could be underlining problems as a result of that day when the car broke down. After some research and speaking with the other service centers "SD Mercedes, MB El Cajon" I would feel more confident and safe to have that engine replaced. (MB El Cajon said they are replacing one of those engine a week ).
Then I got this- rI understand but nothing is wrong with the engine. We replaced the engines sometimes as well but in this case there is no damage to the cylinder sidewalls so there is no need to replace the whole engine, only the piston was cracked. That does cause underlying damage to the turbocharger as well which is why we are replacing that too. Unfortunately mercedes makes dealerships prove every warranty repair we do is needed so they will only allow us to replace what is damaged. The warranty is the same 4 year 50,000 warranty that came with the car at time of purchase, no extension or anything when a warranty repair is done
Any advice how I should address this situation?
UPDATE message from MB
"Just wanted to let you know that your car is all done and ready for the went ahead and replaced both the engine mounts and one transmission mount and that seem to take care of that rough idle"
My 2016 C300 (In-line 4 turbo, "petrol" with 241HP) at 55k miles had the exact same problem, with 1st cylinder cracked, and my car is out of warranty. I talked to my dealership and the Corporate separately.
The dealership would cover the cost of the parts whether the engine needs replacement or not, as I bought my car there new and have been using them through prepaid maintenance. I decided to fix the car and pay them pre-arranged labor.
But here is the response from the Corporate:
Thank you for your email to Mercedes-Benz USA, although we regret to learn of the circumstances that prompted your contact.
While we understand your concerns, all warranty determinations are provided by an authorized Mercedes-Benz dealership upon inspection. If the warranty has expired, there is no obligation on part of the manufacturer, to cover the cost of repairs.
Customers can request goodwill assistance, however which is reviewed on a case by case basis and not guaranteed. It may be helpful for you to know that when reviewing your concern, the vehicle requires an inspection at an authorized Mercedes-Benz dealership, and the following variables would be taken into consideration: vehicle age, mileage, vehicle history, service/repair history (whether maintenance is performed at MB dealers), and brand loyalty. Review for goodwill requests can only be reviewed prior to repairs being performed, as reimbursement is not possible.
So confused. MB OF EC has my car now and first they were curious to why Hoehn only replaced 1 piston and not the other ones. Comfirming that yes it was a piston issue. Then someone else tells me from that dealership that it was the spark plug that caused this whole problem and caused the piston to break? Now I get a call and text saying that they replaced the blower motor and that is what was causing the jerking and vibration of the engine?
So confused. MB OF EC has my car now and first they were curious to why Hoehn only replaced 1 piston and not the other ones. Comfirming that yes it was a piston issue. Then someone else tells me from that dealership that it was the spark plug that caused this whole problem and caused the piston to break? Now I get a call and text saying that they replaced the blower motor and that is what was causing the jerking and vibration of the engine?
get the people to put their responses in writing. If it isn't documented it didn't happen,
***Update*** Here is my question. Can a spark plug failure cause a piston to break and if a piston brakes can that cause spark plug failure?
The reason I ask this is because I have one dealership telling me that my piston broke because of a spark plug failure and then I have another dealership telling me that the spark plug had nothing to do with the piston failing and the Piston breaking so I'm kind of confused
You’re lucky yours lasted till 65k. Mine cracked pistons 1 and 3 at 32k miles! Can’t believe Benz designed the W205/ 274 engine- it’s horrible!
Originally Posted by dimbmw
Maybe someone will find it useful.
California car, W205 C300 4 matic. Slightly over 4 years, about 65K miles.
Timely serviced etc.
Cracked piston in cyl 1.
Mercedes refuses to cover 100% of repair costs , which is in my view ridiculous as cracked piston is not something that normally happens as the result of normal wear and tear, especially in a 4 year old car.
This will be my last Mercedes, lesson learned ! Bye, Mercedes.
You’re lucky yours lasted till 65k. Mine cracked pistons 1 and 3 at 32k miles! Can’t believe Benz designed the W205/ 274 engine- it’s horrible!
You guys should report this to the National Highway Transportation Safety Board. Having the car stop in the middle of the road would be a safety issue and if you had it repair and there's a recall, you would get reimbursed. Or even if there's an extended warranty. If there's a few hundred complaints, something might happen.
Why would only piston 1 would crack? (I have only seen 2 occasions of 1 and 3.) Would anybody know this? So the other wrist pins are Ok? Hard to believe that all others would last as long as the new replaced one. Just thinking.
How did those bearings look? (I ask because I wonder now if we have a mini M3 S65 engine) Man those pistons look skinny lol. I guess something went wrong with the casting process on certain C300s with their pistons? Sucks.
Internals aren't nearly as thick as the 2GR-FSE engine... kind of disappointing at this price point. Thiccc Steel forged crankshaft 6 bolt structure holds each main bearing
Diagram from the PDF document called something like "Introduction of the M274": M274 Crank. Case closed?
Last edited by draemux; 11-29-2020 at 08:37 AM.
Reason: Diagram for people who don't know what I'm talking about.
I am having a simliar issue that has been discussed on this thread except my 2015 C Class has the V6. Compression is down (50psi) in #4 Cylinder and the motor is skipping ( once it warmes up a bit) They report the misfire valve is not high enough to trigger check engine light right now. . Mercedes dealer has diagnosed the problem to be valve related and calling for the head to be replaced. They are suggesting a manual Leak Down test and compression test to test to verify. Can anyone comment on weather this problem is being reproted on the V6 with any frquecy. I am affraid to have them open it up and find more issues like the a cracked cylinder head. etc
So sorry for everyone's troubles with this issue. A piston should not be cracking at 65,000 miles. The pistons being used sure look pathetically skinny and not durable. MB sure doesn't make them like they used to. Makes me love my W201 all the more.
You guys should report this to the National Highway Transportation Safety Board. Having the car stop in the middle of the road would be a safety issue and if you had it repair and there's a recall, you would get reimbursed. Or even if there's an extended warranty. If there's a few hundred complaints, something might happen.
I agree but few will report a car problem to the govt., even if its a clear safety issue. I once checked NHTSB reports for an expensive Porsche Cayenne electrical problem that is a definite safety issue and is very commonly reported on the Porsche forums. No one had ever filed a report with NHTSB.
Thankful for this board and this thread. Glad I did the research. I was getting ready to purchase one with a manufacturing date of 10/2014 tonight. Dodged that bullet.
I had the exact same thing happen to me last month. I bought a preowned 2017 C300 30k miles on it still under factory warranty. Im in Los Angeles. The engine started losing power and wobbling on the highway and its scary. Argued with an MB rep over phone but to no effect...still they replaced only the piston and not the whole engine. Planning to call them this week to as them a reason for the pistion failure in writing. Im thinking they could be a lawsuit here somewhere. Getting half assed repairs for a $60K car doesnt feel fair. Its a scary experience to have your engine go out on you on the highway. I think if we deal with them individually they are taking advantage of us. If we group together then its a lot more scarier for them. What are the steps needed for a class action lawsuit? Any thoughts?
I just had the same problem, are you still working with the lawsuit or are you done with the process?
08-15-2020 | 09:38 AM
