so my 2014 GL550 developed a knocking noise, checked by dealer as cylinder scoring. Now 10,000 miles plus after from last year, its still running strong. yes it knocks, but still same power, no loose compression, (I thing mpg got little better)

maybe I can just run it for another 2-3 years, or maybe indefinitely ?

wondering your thoughts? how long can I run an engine after cylinder scoring?

it has now 100,500 miles, problem started at around 88,000

why fix it? its a "dead engine running"


any thoughts?

 

OH, I forgot, just did an oil change few weeks ago, knocking went little quieter, still there, just like driving a diesel......

interesting is that when its cold, for first 2-3 minutes there is no knocking, only when its warm. Makes me think maybe its something else.

but I will give it another 10-12K miles and report back

 

So we took a trip Wisconsin on 93 octane, watched carefully what mpg was, then on I way back, filled up with pure gasoline no ethanol added… same way back almost 2 mpg more

 

no offense but have you tried bluetec's you cant tell difference in noise. Anyhow you got 6 or 8 cylinder ? and how many knocks ?

 

Knocking noise is knocking noise. I am not sure if it is related to scoring. Could be something else. Try heavier oil, could be lack of oil pressure.

 

Go to some good mechanic, and try localize sound origin. Don't give any details as scoring etc to avoid biased diagnosis

 

Agreed, get it tested. I got so many different diagnosis from the dealer and independent shops. including it being scoped and each shop finding different cylinders sored. Then it turns out once it was torn down it was an assembly defect, which should have been under warranty. But mine did drive fine for a pretty much a year with no adverse effects save for the noise. Power and economy was good.

 

Thanks for all of the replies everyone. I appreciate the input, as this is a challenging situation and a big disappointment. I have taken this issue up with MB HQ in the US and they took in my case problem with a “Business Referral Executive,” apparently their last line of customer service defense. They connected with the dealer, who I will say has been supportive of my issue with loaner cars and ensuring me their best AMG mechanic has done his best assessment without disassembling the whole engine. They also agreed the car was in great shape and serviced appropriately. After Mercedes HQ directed the service manager to inspect a few further areas, they called me back a week later and said they will offer no goodwill assistance on the repairs as the car is out of warranty, and doesn’t qualify it for any further consideration. The rep was unable to reason with and very robotic in his responses. He even told me that he couldn’t provide any “hypothetical” solutions to my problem as a customer who was considering buying a new car, of which could have been a mercedes. Needless to say. I’m very disappointed in MB in how they handled the situation. They knew I was ready to buy another car after the last repair, and they don’t seem to care about the situation or whether I remain a MB customer.

I’ve decided to take the car to another shop that’s not a dealer, that specializes in Mercedes repairs, to get their opinion. I’ve also started getting quotes from companies like CarBrain to just scrap the car and take it off my hands. If I had more time and didn’t have a demanding job and family responsibilities like most, I’d consider completely disassembling the engine with a good mechanic or replace with a used engine, but I am officially done with Mercedes.
It’s too bad because I enjoy driving these cars, but this is a tough pill to swallow. Thanks again for all the feedback for a first time poster. To someone’s post earlier, you don’t hear about the cars that are running perfectly, only when there’s a problem, which is true. However, I wish the company stood behind their product more. Personally, I’m going to explore other brands and if German like Porsche or Audi, I will make sure I drive it under warranty. Lesson learned. Thanks again everyone.

 

I do think getting an opinion on the potential scored cylinders would be helpful. I had rhe local dealer twice scope it and twice lie to me about it. My actual engine was rebuilt by a member here and his evidence was very different from what the dealer said.
I don't think there is an easy solution. the value of the car at this point is well back from the repair cost. Sucks but that is the realtiy.

 

Yes driving with scored cylinder is ok. Knock could be piston slap but usually only happens on start ups. Doesn’t seem to be common on these. You have two choices. Change oil at a reasonable interval don’t scope lol and make it a point to reach 200k on the odo. Or scope and freak the hell out. Trade in, crash it or burn it. Get some layers to open up a class action lawsuit.

MB dropped the ball on the piston coating and cylinder material choice. Not enough durability data before bringing it to market. They were trying to catch up with BMW and Audi with forced induction tech and fuel economy. Porsche stuck their foot in the mouth aswell. And that ridiculous oil change interval just makes things worse.

if you don’t have excessive blow by or oil consumption just drive it. Resale value is a joke in these for older units so if you get 3/36k you basically leased a car.

not sure how else to paint the picture. GL owners are not the only folks with this predicament.