Is It Worth Fixing A Mercedes-Benz GL 63 AMG?

JUPITER, FL – It’s a challenging problem involving a luxury SUV that has a potentially high price tag to rectify; as much as $20,000 or more. There’s no easy solution for a friend who owns a 2014 Mercedes-Benz GL 63 AMG that has developed an engine issue. Simply put, my friend is likely screwed no matter the outcome.

The model had an original base price of $118,160 but with upgrades, including a $6,000 entertainment system and Designo interior, it cost upwards of $150,000 when new. My friend got the SUV used at a Florida car dealer in December 2022. He has driven it responsibly and serviced it regularly. He has full records dating back to its original purchase and it has always been serviced by a Mercedes-Benz dealer.

How Can This Happen With Mileage So Low?

What makes this tale noteworthy is that it has only 38,445 miles on the odometer. Remember that number. That’s less than 4,000 a year, an incredibly low amount. Much of the mileage my friend has put on the GL 63 has been on I-95 between his summer house in Connecticut and his winter condo in Florida.

2014 Mercedes-Benz GL 63 AMG

It was a few weeks ago when he was in CT for his mother’s funeral that the “check engine” light came on. He’d noticed that the high-performance M157 engine would occasionally sputter. Before attempting the ride back to FL – a trip that I agreed to serve as relief driver on – he took it to his mechanic.

Error Code Provides A Clue

The shop’s owner did a computer diagnostic and got a P030585 error code, meaning that the fifth cylinder wasn’t firing properly. He suggested that a simple fix should be tried first. Maybe the fuel injector was dirty, so try adding some fuel injector cleaner to the gas tank on the way South. My friend did so. He also switched to the recommended premium gas instead of the occasional regular he had been putting in the SUV.

We left Connecticut on Feb. 7 and took three days to make the 1,325-mile drive that was largely uneventful. The engine only acted up once or twice.

Upon getting to Florida, and with the check engine light still illuminated, my friend took the GL 63 to a high-end repair shop that he’s used in the past for his other Mercedes-Benz vehicles. He trusts the shop for a factual consult because the technicians and owner are Mercedes-Benz trained. They worked years for a Mercedes-Benz dealership.

Within a day or two, he was told the fifth cylinder had low compression and an exhaust valve leak and that it would could cost $15,000 to $20,000 to repair. For a model with fewer than 40,000 miles on the engine.

The Issue Apparently Isn’t Uncommon

Being the curious sort, my friend started doing online research and soon learned from the MBWorld forum and other websites that his problem hasn’t been uncommon. High-performance AMG models sold by Mercedes-Benz have engines that are hand built. Each was signed by the engine builder himself.


Based on comments from other Mercedes-Benz owners, it seems on some models that a valve guide and seal installation tool used to install the guides resulted in improper installation. This later resulted in the engine issue.

It’s An Unappealing Situation

None of the options now presented to my friend are appealing. Any fix will require that the engine be dropped from the GL 63 to determine the actual repairs required; at a cost of $5000. While the problem may be something simple like a bad valve spring, the SUV could require that the head or both heads be replaced. Either way, the job will be costly. Is it worth putting $20,000 or more into a car that might only have a trade-in value of $25,000-$30,000 when fixed?

Thinking a dealer might be able to fix it for much less, then flip it and still make a profit, my friend went to a luxury car lot a few days ago seeking guidance. He asked if the store would be interested in buying it as-is. The answer was no thank-you.

The GL 63 AMG Looks Like New

Yes, the GL 63 is 10 years old. But it is immaculate.

Yes, it is long out of warranty. But, no matter its age, no vehicle with such low mileage, and always serviced by Mercedes-Benz, should ever have such a major failure. The issue is apparently known by Mercedes-Benz, according to my friend’s research, making it reasonable for the manufacturer to offer assistance and relief.

My friend has owned several of the brand’s models in the past, but his loyalty is now being tested. He has called the customer assistance center at Mercedes-Benz USA, which opened a case file and instructed him to bring the GL 63 into a dealer for a second costly diagnosis. He had already paid more than $700 for the look-see at the other shop at this point.

The GL 63 AMG Is Now At A Dealer

After getting an appointment at a local Mercedes-Benz dealer, he took it there on Monday and was told the diagnostic charge would be $1,200 and that it would take two or three days to get any answers.

The GL 63 has now been at the dealer for two days without being looked at. After being without a car for a few days after taking the SUV to the first shop, my friend is now driving a rental car because the dealer doesn’t have a loaner available. That’s more money out of his pocket.

It’s A No-Win Situation For All Involved

He’s in a no-win situation that will quite likely be very expensive for a problem that never should happen to any vehicle with so few miles. Given the history of the GL 63 AMG with the M157 engine, with signs pointing to the problem originating during the build process, the owner understandably feels the manufacturer needs to step up and offer full assistance.

Anything less and Mercedes-Benz’s reputation will take a hit.

I’ve withheld the name of the owner of the GL 63 AMG as it’s early in the process. He doesn’t wish to rile anyone and he’s hopeful that Mercedes-Benz will provide a positive resolution. What has happened to his SUV, though, is sufficiently out of the ordinary to be newsworthy. A follow-up will be written at the proper time.

About Bud Wilkinson

Bud Wilkinson writes the "RIDE-CT" motorcycle column and the "My Ride" classic car feature in the "Republican-American" newspaper in Waterbury, CT. A graduate of Vermont Academy prep school, he holds a B.A. degree journalism from Ohio Wesleyan University. He is the recipient of a Scripps Howard Foundation National Journalism Award in 1992 and a 1991-92 regional Emmy Award for commentary. He currently rides a 1987 BMW R 80 RT and a 2014 Triumph Bonneville and drives a 2010 Mazda MX-5 Miata.

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