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I'm GLC 2018 owner and this concerns me a lot. I just checked the consumer reports and believe it or not GLC has no major engine issues reported.
I would recommend to contact consumer reports and BBB to report, maybe they can help
Also can you please post the VIN numbers?
I also used consumer reports before buying a 2019 CPO GLC300. Seems like they captured the earlier 2016 wrist pin issues in their reliability ratings.
As for all M274s, I am curious what % of all GLC300s will actually get a cracked piston? If it's a lot, then yeah I don't understand the discrepancy. in the Consumer reports rating.
I also used consumer reports before buying a 2019 CPO GLC300. Seems like they captured the earlier 2016 wrist pin issues in their reliability ratings.
As for all M274s, I am curious what % of all GLC300s will actually get a cracked piston? If it's a lot, then yeah I don't understand the discrepancy. in the Consumer reports rating.
Ever thought that it most likely is "not a lot", and therefore not mentioned in the consumer reports? Sorry, but it seems like there is only a handful of suspects here that always complain and rant about it, and share this negative news, ........ many jump on it.
As you stated yourself: "I am curious what % of all GLC300s will actually get a cracked piston?" And this engine is not only used on the GLC, so one should ask how many of these M274 engines have the failure? Can you imagine how many of these engines are installed on cars all over the world? A few isolated cases do not make it a piece of crap, even though many here do think so.
As mentioned before, there is no such thing as a bullet proof car/engine, and one needs to maintain it and treat it correctly with oil change intervals, using the correct gasoline, etc.
No Honda or Toyota will run forever if one does not change the oil, ............................ just saying.
As I have stated in the past,
I believe gasoline quality and spec discrepancies are the biggest cause of these pre ignition/detonation failures reported sporadically on MULTIPLE manufacturer internet message boards like mbworld.com
These modern 4 cylinder engines (all brands) are pushing the performance and efficiency envelope, thereby reducing the engineering margin of safety.
Last edited by crconsulting; Feb 2, 2023 at 11:54 AM.
As I have stated in the past,
I believe gasoline quality and spec discrepancies are the biggest cause of these pre ignition/detonation failures reported sporadically on MULTIPLE manufacturer internet message boards like mbworld.com
These modern 4 cylinder engines (all brands) are pushing the performance and efficiency envelope, thereby reducing the engineering margin of safety.
I'm amazed that we see 476hp out of MBs 2 liter four. Sounds like a ticking time bomb.
I'm not sure I'd call them overstressed, though.
Progress in managing flame fronts, spark plug and combustion chamber design, have reduced instantaneous loads, and it's possible that they are reduced in important parts of the cycle.
Improved oils, hollow crank lubrication improvements, 48v cooling, metallurgy - all that modern stuff, may make these engines less stressed than 245hp out of the 87 Buick GNX's 3.6 liters. Or 282hp out of the terrorizing 78 930 Turbo's 3.0.
There must be a limit, I suppose, but I can't guess where it is.
2016 S550 sport, 2018 GLC300, M3, Zo7, 2021 Sierra Denali
None of us will ever know the real number of failures. MB will never let that be known. Then there are those out of warranty that arent on forums who just sold the car as is or did an independant repair. There are many posts on several forums for some time now, and now that the mileage is getting higher there seem to be more popping up. I have a vested interest in knowing but am not interejcting a bias towards "its nothing" to make myself feel better which is what some are doing. No car should have such an issue at all especially under 75K properly maintained. Yet they are happening. Its an obvious defect as its the exact same issue. I have an unlimited MB 2 yr extended warranty. In two years I will figure whether I am in or out, but not risking a 12-20K repair on a used cheap truck.
MB is clearly just trying to get though the warranty period. Its a financial decision as thats the cheaper way to go for them. That doesnt mean its not a real problem.
Well I just did my trans service at my trusted independant shop who has a former Mercedes tech. His words when I asked him his opinion on the motor. "well I can tell you I changed alot of motors in that generation truck" !!!! He said its a real problem, he wouldnt own one. Thats one tech in one dealership with only that exposure....think about that. Think about what we dont know. Everyone who owns a MB is not an enthusiast or on a forum. This can be an echo chamber. But my techs experience speaks volumes.
There are known issues with many manufactures. Just because it didnt happen or happen yet doesnt mean it wont. Where there is smoke there is fire.
I had an E46 M3..........Huge SMG trans problem with that generation. Great car in 100 ways...but there is no denying the issue. Mileage got higher more SMG reports. It took many years for it to BE KNOWN. The same is happening here. Why people deny something because it isnt presently happening to them I dont know. Will they come back if it happens and say I was wrong??
None of us will ever know the real number of failures. MB will never let that be known. Then there are those out of warranty that arent on forums who just sold the car as is or did an independant repair. There are many posts on several forums for some time now, and now that the mileage is getting higher there seem to be more popping up. I have a vested interest in knowing but am not interejcting a bias towards "its nothing" to make myself feel better which is what some are doing. No car should have such an issue at all especially under 75K properly maintained. Yet they are happening. Its an obvious defect as its the exact same issue. I have an unlimited MB 2 yr extended warranty. In two years I will figure whether I am in or out, but not risking a 12-20K repair on a used cheap truck.
MB is clearly just trying to get though the warranty period. Its a financial decision as thats the cheaper way to go for them. That doesnt mean its not a real problem.
Well I just did my trans service at my trusted independant shop who has a former Mercedes tech. His words when I asked him his opinion on the motor. "well I can tell you I changed alot of motors in that generation truck" !!!! He said its a real problem, he wouldnt own one. Thats one tech in one dealership with only that exposure....think about that. Think about what we dont know. Everyone who owns a MB is not an enthusiast or on a forum. This can be an echo chamber. But my techs experience speaks volumes.
There are known issues with many manufactures. Just because it didnt happen or happen yet doesnt mean it wont. Where there is smoke there is fire.
I had an E46 M3..........Huge SMG trans problem with that generation. Great car in 100 ways...but there is no denying the issue. Mileage got higher more SMG reports. It took many years for it to BE KNOWN. The same is happening here. Why people deny something because it isnt presently happening to them I dont know. Will they come back if it happens and say I was wrong??
Just because there are owners which are not on a forum does not mean that their cars are failing, as it could be quite the opposite and they do not fail. However, that info as well is not known.
The internet states that just in the US, last year MB sold 51,805 GLC‘s, and that is in the US alone. So since the model came out, and we consider the somewhat same trend for all the years, that would be at least 250,000 cars. How many you think that is worldwide, and what percentage do you think shall fail?
How many motors are “a lot” that your mechanic changed? 5? 20, 50???? And I say it again as stated many times before, was the vehicle properly maintained and treated, did someone pull it out of the garage and kicked the snot out of it while it was ice cold, was high octane gasoline used, ……… etc., blah, blah, blah.
You are correct, we will never know.
Previous generations had the balance shaft issue. Did every engine fail, or some?
Funny thing is, I know a MB Mechanic who is still actively working at MB, he acknowledges the problem as it does exist, but feels it’s blown way out of proportion.
Will you come back if nothing happens to you and tell me I was wrong?
I think we can continue to play this game for a very long, long time. Go buy a Lexus.
Last edited by S70Houston; Feb 3, 2023 at 11:39 PM.
None of us will ever know the real number of failures. MB will never let that be known. Then there are those out of warranty that arent on forums who just sold the car as is or did an independant repair. There are many posts on several forums for some time now, and now that the mileage is getting higher there seem to be more popping up. I have a vested interest in knowing but am not interejcting a bias towards "its nothing" to make myself feel better which is what some are doing. No car should have such an issue at all especially under 75K properly maintained. Yet they are happening. Its an obvious defect as its the exact same issue. I have an unlimited MB 2 yr extended warranty. In two years I will figure whether I am in or out, but not risking a 12-20K repair on a used cheap truck.
MB is clearly just trying to get though the warranty period. Its a financial decision as thats the cheaper way to go for them. That doesnt mean its not a real problem.
Well I just did my trans service at my trusted independant shop who has a former Mercedes tech. His words when I asked him his opinion on the motor. "well I can tell you I changed alot of motors in that generation truck" !!!! He said its a real problem, he wouldnt own one. Thats one tech in one dealership with only that exposure....think about that. Think about what we dont know. Everyone who owns a MB is not an enthusiast or on a forum. This can be an echo chamber. But my techs experience speaks volumes.
There are known issues with many manufactures. Just because it didnt happen or happen yet doesnt mean it wont. Where there is smoke there is fire.
I had an E46 M3..........Huge SMG trans problem with that generation. Great car in 100 ways...but there is no denying the issue. Mileage got higher more SMG reports. It took many years for it to BE KNOWN. The same is happening here. Why people deny something because it isnt presently happening to them I dont know. Will they come back if it happens and say I was wrong??
2016 S550 sport, 2018 GLC300, M3, Zo7, 2021 Sierra Denali
Originally Posted by mikapen
It was, until we saw another (somewhat preposterous) hearsay tale from a mechanic. It destroys the rest of the message.
Preposterous?/ Hmmm, Hearsay? So you are calling me a liar? So I relate the mans words to me and now its hearsay and we are in court?? Your critique and commentary can be construed as insulting. The post is my opinion with the fact of what the tech said. Take it for what its worth no need for your derogetory commentary. Personally I prefer this issue to be small, unfortunately as time and mileage grow so seems the number of issues. We shall see.
2016 S550 sport, 2018 GLC300, M3, Zo7, 2021 Sierra Denali
Originally Posted by S70Houston
Just because there are owners which are not on a forum does not mean that their cars are failing, as it could be quite the opposite and they do not fail. However, that info as well is not known.
The internet states that just in the US, last year MB sold 51,805 GLC‘s, and that is in the US alone. So since the model came out, and we consider the somewhat same trend for all the years, that would be at least 250,000 cars. How many you think that is worldwide, and what percentage do you think shall fail?
How many motors are “a lot” that your mechanic changed? 5? 20, 50???? And I say it again as stated many times before, was the vehicle properly maintained and treated, did someone pull it out of the garage and kicked the snot out of it while it was ice cold, was high octane gasoline used, ……… etc., blah, blah, blah.
You are correct, we will never know.
Previous generations had the balance shaft issue. Did every engine fail, or some?
Funny thing is, I know a MB Mechanic who is still actively working at MB, he acknowledges the problem as it does exist, but feels it’s blown way out of proportion.
Will you come back if nothing happens to you and tell me I was wrong?
I think we can continue to play this game for a very long, long time. Go buy a Lexus.
Its not a game, they were opinions, and thoughts on the subject...kind of what forums are for. You have yours and I have mine, thats how it works. Who put you in charge of telling people what they should buy?? Pretty full of yourself huh? I may be disappointed and concerned but I will drive and own what I like. Carry on.
Sorry to interrupt but I thought I'd re-post part of an entry from the " Cracked Piston No. 2 Cylinder" thread on this site. An extract from a Petroleum Quality Institute of America (PQIA) paper:
"The SN PLUS Service Category was introduced as a supplement to API SN specification in 2018 to mitigate low speed pre-ignition (LSPI) events in Turbocharged Gasoline Direct Injection (TGDI) engines. Such LSPI events can cause engine knocking, decreased efficiency, and in the worst case, catastrophic failure due to cracked pistons."
So, an entirely new API oil formulation was developed (with some urgency) specifically to address the cracked piston issue on TGDI engines. Neither the API nor the PQIA mention MB because this problem exists for ALL small-displacement, high output TGDI engines. We can debate endlessly about the issue as it relates to MB (this is an MB site after all), but to attribute the problem specifically and exclusively to MB is totally inaccurate and misleading. A quick scan of other forums will confirm that Audi, Volvo, GM, BMW and others using small displacement TGDI engines are encountering similar cracked piston/broken piston ring issues.
Preposterous?/ Hmmm, Hearsay? So you are calling me a liar? So I relate the mans words to me and now its hearsay and we are in court?? Your critique and commentary can be construed as insulting. The post is my opinion with the fact of what the tech said. Take it for what its worth no need for your derogetory commentary. Personally I prefer this issue to be small, unfortunately as time and mileage grow so seems the number of issues. We shall see.
You sure it is me who is “full of myself”???? ……. Just listen to yourself, I beg to differ.
You just want and hope that everyone agrees with your opinion. Well, unfortunately not. You know why, ……… “kinda what forums are for”. SMH!
Sorry to interrupt but I thought I'd re-post part of an entry from the " Cracked Piston No. 2 Cylinder" thread on this site. An extract from a Petroleum Quality Institute of America (PQIA) paper:
"The SN PLUS Service Category was introduced as a supplement to API SN specification in 2018 to mitigate low speed pre-ignition (LSPI) events in Turbocharged Gasoline Direct Injection (TGDI) engines. Such LSPI events can cause engine knocking, decreased efficiency, and in the worst case, catastrophic failure due to cracked pistons."
So, an entirely new API oil formulation was developed (with some urgency) specifically to address the cracked piston issue on TGDI engines. Neither the API nor the PQIA mention MB because this problem exists for ALL small-displacement, high output TGDI engines. We can debate endlessly about the issue as it relates to MB (this is an MB site after all), but to attribute the problem specifically and exclusively to MB is totally inaccurate and misleading. A quick scan of other forums will confirm that Audi, Volvo, GM, BMW and others using small displacement TGDI engines are encountering similar cracked piston/broken piston ring issues.
2016 S550 sport, 2018 GLC300, M3, Zo7, 2021 Sierra Denali
Originally Posted by S70Houston
You sure it is me who is “full of myself”???? ……. Just listen to yourself, I beg to differ.
You just want and hope that everyone agrees with your opinion. Well, unfortunately not. You know why, ……… “kinda what forums are for”. SMH!
Exactly what you seem to suffer from. Needing everyone to see your light and opinion as gospel and correct. Its nothing more than opinion where you attack opposing opinions. Ridiculous. Again the authority and all knowing not only tells all what they should drive and what they should think. Now your a psychic and know what I "hope". Give me a break. Can't let it go, and ignore? You said your peace but need to chew into the gutter. Have fun.
2016 S550 sport, 2018 GLC300, M3, Zo7, 2021 Sierra Denali
Originally Posted by karmikan
Sorry to interrupt but I thought I'd re-post part of an entry from the " Cracked Piston No. 2 Cylinder" thread on this site. An extract from a Petroleum Quality Institute of America (PQIA) paper:
"The SN PLUS Service Category was introduced as a supplement to API SN specification in 2018 to mitigate low speed pre-ignition (LSPI) events in Turbocharged Gasoline Direct Injection (TGDI) engines. Such LSPI events can cause engine knocking, decreased efficiency, and in the worst case, catastrophic failure due to cracked pistons."
So, an entirely new API oil formulation was developed (with some urgency) specifically to address the cracked piston issue on TGDI engines. Neither the API nor the PQIA mention MB because this problem exists for ALL small-displacement, high output TGDI engines. We can debate endlessly about the issue as it relates to MB (this is an MB site after all), but to attribute the problem specifically and exclusively to MB is totally inaccurate and misleading. A quick scan of other forums will confirm that Audi, Volvo, GM, BMW and others using small displacement TGDI engines are encountering similar cracked piston/broken piston ring issues.
Encouraging info that great properly maintained GLC's should avoid this issue. Unfortunately some of the posts claim perfect maintenance at MB?/ Who knows?, I'll keep using the proper oil and filters hoping to avoid it.
Exactly what you seem to suffer from. Needing everyone to see your light and opinion as gospel and correct. It’s nothing more than opinion where you attack opposing opinions. Ridiculous. Again the authority and all knowing not only tells all what they should drive and what they should think. Now you’re a psychic and know what I "hope". Give me a break. Can't let it go, and ignore? You said your peace but need to chew into the gutter. Have fun.
No further comment to this, or any other of your threads.
Preposterous?/ Hmmm, Hearsay? So you are calling me a liar? So I relate the mans words to me and now its hearsay and we are in court?? Your critique and commentary can be construed as insulting. The post is my opinion with the fact of what the tech said. Take it for what its worth no need for your derogetory commentary. Personally I prefer this issue to be small, unfortunately as time and mileage grow so seems the number of issues. We shall see.
Quote from you: "His words when I asked him his opinion on the motor. "well I can tell you I changed alot of motors in that generation truck" !!!!"
Hearsay? Definitely.
Liar? No.
Useful information? No
Able to answer follow-up questions? No.
Attacking multiple posters instead of answering multiple requests/comments doesn't make your tale more believable.
Quote from you: "His words when I asked him his opinion on the motor. "well I can tell you I changed alot of motors in that generation truck" !!!!"
Hearsay? Definitely.
Liar? No.
Useful information? No
Able to answer follow-up questions? No.
Attacking multiple posters instead of answering multiple requests/comments doesn't make your tale more believable.
Try answering the questions. That usually helps.
Why do you even still respond mikapen? Just let it go, .............................
2016 S550 sport, 2018 GLC300, M3, Zo7, 2021 Sierra Denali
Originally Posted by mikapen
Quote from you: "His words when I asked him his opinion on the motor. "well I can tell you I changed alot of motors in that generation truck" !!!!"
Hearsay? Definitely.
Liar? No.
Useful information? No
Able to answer follow-up questions? No.
Attacking multiple posters instead of answering multiple requests/comments doesn't make your tale more believable.
Try answering the questions. That usually helps.
There is no questions to answer. There is no attack. Entitled to your opinion. I took the mechanics statement with a grain of salt. May have been bolstering himself infront of his new boss?....I still didnt like hearing it, I figure its a concern, not gospel or written proof. Again we shall see. Have a great day!
My 2018 C300 C Class Coupe M274 E20 GA 205.348.22-AU3 had a catastrophic engine failure at just over 10,000 Kms.
Diagnosis thus far is that Cylinder 1 Piston is cracked. Codes I was able to catch after the engine would no longer start and the check engine light was displayed. I had a OBD2 reader lying around after doing work on a friends car. Downloaded the full license for my car.
P030085 Combustion misfiring has been detected.
P030185 Combustion misfiring of cylinder 1 has been detected.
P030285 Combustion misfiring of cylinder 2 has been detected.
P030385 Combustion misfiring of cylinder 3 has been detected.
I had been on the road for less that 4 mins, when the car lost all power while accelerating from 40km - 70km. Prior to this no warning indicators had been displayed in the dashboard instrument cluster, no warnings were even displayed when the engine failed.
The vehicle is 90% driven within the CBD and surrounding suburbs within 15km.
During the last 6 months it is primarily driven in comfort mode due to increasing petrol costs.
The vehicle always receives premium petrol being Shell V-Power 98 (90% of the time) and BP Ultimate Unleaded 98 (10% the remainder) with no additional performance additives.
The vehicle is well serviced, very well maintained, in exceptional overall condition.
The never put under load or driven above 3800 rpm unless at operating temperature of approx. 95. deg C.Other premature failures include.
Exhaust Camshaft magnet o-ring failed @ 9,893 KM
Alternator Belt Pulley bearing Leaking leaking likely much before 10,688 when I picked it up.
Ticking noise on Cold Start at reported @ 4,425 Km which would remain until the engine had warmed.
I will be pursuing a claim with Mercedes Benz Australia under Lemon Laws and seek an entire engine replacement.
Whist my car is approx. 9 months outside of MB 2 year manufacture warranty Australian Consumer Law, specifically Consumer Guarantees for products stipulate all Australian businesses must provide a set of "automatic guarantees" regardless of standard manufacture warranties given or sold.
Took a while but MB finally agreed to repair the engine 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. 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 ??
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
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.
New Engine Number : Teil-Nr is the Long Block part number
Took a while but MB finally agreed to repair the engine 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. 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 ??
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
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.
New Engine Number : Teil-Nr is the Long Block part number
Thank you for the update, glad to hear it worked out for you.
These engines are noisy anyhow, a lot of injector noise. It looks like you have a trick carbon fiber valve cover on it. The stock beauty cover would mask some of the noise. My 2015 Q5 TDI was quieter than my 2019 GLC. I don't trust any mechanic anymore, with the exception of my Kia mechanic (40 year master mechanic). Good thing you did an inspection right away.
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