Man was given a free Mercedes GL450 on the condition he could fix it after two mechanics failed to get it running
Published on Sep 10, 2026 at 3:31 PM (UTC+4)
by Henry Kelsall
Last updated on Sep 10, 2026 at 3:32 PM (UTC+4)
Edited by
Ben Thompson
A man was given a free Mercedes GL450 SUV on the condition that he could fix it, after two mechanics failed to get it running.
YouTuber Waldo from Waldo’s World had been given the car after two mechanics decided it needed a new engine due to cylinder damage.
The car did run and drive, but replacing the engine in it would have cost a fortune.
So Waldo decided to see if he could fix it without replacing the engine and effectively get a Mercedes SUV for free.
What was wrong with the Mercedes GL450?
Owner Ray had offered the car to Waldo on the condition that he could actually get the Mercedes SUV running again.
“Even though the car runs and drives, it’s been to two different mechanics, both of whom have said it needs a new engine,” Waldo said.
His challenge was to fix it without breaking the bank and without having to pay for a new engine.
“When I start it up, you can see that the check engine light is on and sometimes it’s flashing,” the YouTuber confirmed.
So there were immediate signs that the Mercedes GL450 had an issue.
The engine codes revealed two were for a cylinder five misfire.
“Now the task at hand is determining the cause of this misfire,” said Waldo.
Waldo got to work fixing the Mercedes SUV
Waldo had some details from the other mechanics he could refer to.
They said they saw bad cylinder scarring.
This can cause a loss of compression and lead to a misfire.
But a compression and spark test showed that cylinder five was functioning normally.
That led Waldo to ponder what might actually be wrong, and that led him to the ECU.
But there was another fault that the YouTuber was able to recognize.
After changing the engine oil, the old oil was incredibly dark and even had a smell of fuel in it.
After changing the oil, a cylinder five injector electrical and open-circuit fault was then found.
That reinforced Waldo’s belief that a new ECU was required.
Waldo pursued the ECU issue with the SUV
A new ECU was bought, with the data from the original cloned into a 2013 GL450 ECU that Waldo bought online.
After installation, he fired the Mercedes SUV up again.
Incredibly, the ECU had been the problem all along, and it was running smoothly with no check engine light.
“Wow, this is amazing. I think that really fixed the issue,” the YouTuber exclaimed.
Waldo concluded that oil migration through the engine wiring harness may have damaged the ECU.
That is a known issue on these particular Mercedes powertrains.
In his view, the previous mechanics simply jumped to conclusions too quickly about the engine issues on the car.
His video showed that just a little bit of digging can help save a car that otherwise could have been broken up for spare parts.
Henry joined the Supercar Blondie team in February 2025, and since then has covered a wide array of topics ranging from EVs, American barn finds, and the odd Cold War jet. He’s combined his passion for cars with his keen interest in motorsport and his side hustle as a volunteer steam locomotive fireman at a heritage steam railway.
