My history with the GL550
Thread Starter
Newbie
Joined: Jan 2026
Posts: 1
Likes: 0
My history with the GL550
I thought I should share my experience with my 15 GL550 over the years. I got it used, and the previous owner had put in about 50k miles. I have done on average 15k miles per year since '21. I obviously have done a few things wrong here 
When I bought the truck, I could not find any record of the spark plugs being replaced. The CEL light would pop on and off with the associated engine jerkiness. Because it was coming on and off infrequently, I didn't get it fixed but suspected the spark plugs. I had also taken it for oil changes and other routine stuff and no one mentioned the spark plugs needing replacement. Well, it got worse, and I had to take it in and, of course, that's exactly what it was. $1,200 later (with ignition coils) it was up and running. I cannot repair a car even if I try to, so I have to use an Indy shop when it comes to maintenance and repairs.
The real fun started as the truck approached 100,000 miles. Long story short, let's just say the entire engine cooling system and suspension (rear and front) broke. With the cooling system, there would be one or two parts of the system breaking over time. With the suspension, the front and rear broke at different times. Over that one-to-two-year time frame, I must have dropped around 15k on repairs and maintenance. Lesson learned from that time period: the car warns you, and you have to take action. For example, the coolant system. I would get random low coolant messages, and they would go away, and I would therefore ignore them. Until you are on the road, smokish stuff coming out of the hood, and you have an "engine hot and will cut off" message. Once you start seeing the truck sag at the rear, your airmatic system is cooked, even if it corrects shortly after. I suspect the pump will die, but I am putting less mileage on this truck and everything is working so far, so I will change it, together with a few minor annoying things, maybe later this year.
Assuming this is it, then these repairs should be good for at least 30,000 miles. That's possibly 3–4 years at my current mileage. I have to say she is driving like a dream. I have other smaller cars with similar power ratings, but the GL still makes me smile every time I am driving her. The repairs are worth every penny. By the way, I bought the GL for around $40k. With the repairs, I am around $55k all in. Where are you going to get a $55k ish truck with the utility of the GL550?
When I bought the truck, I could not find any record of the spark plugs being replaced. The CEL light would pop on and off with the associated engine jerkiness. Because it was coming on and off infrequently, I didn't get it fixed but suspected the spark plugs. I had also taken it for oil changes and other routine stuff and no one mentioned the spark plugs needing replacement. Well, it got worse, and I had to take it in and, of course, that's exactly what it was. $1,200 later (with ignition coils) it was up and running. I cannot repair a car even if I try to, so I have to use an Indy shop when it comes to maintenance and repairs.
The real fun started as the truck approached 100,000 miles. Long story short, let's just say the entire engine cooling system and suspension (rear and front) broke. With the cooling system, there would be one or two parts of the system breaking over time. With the suspension, the front and rear broke at different times. Over that one-to-two-year time frame, I must have dropped around 15k on repairs and maintenance. Lesson learned from that time period: the car warns you, and you have to take action. For example, the coolant system. I would get random low coolant messages, and they would go away, and I would therefore ignore them. Until you are on the road, smokish stuff coming out of the hood, and you have an "engine hot and will cut off" message. Once you start seeing the truck sag at the rear, your airmatic system is cooked, even if it corrects shortly after. I suspect the pump will die, but I am putting less mileage on this truck and everything is working so far, so I will change it, together with a few minor annoying things, maybe later this year.
Assuming this is it, then these repairs should be good for at least 30,000 miles. That's possibly 3–4 years at my current mileage. I have to say she is driving like a dream. I have other smaller cars with similar power ratings, but the GL still makes me smile every time I am driving her. The repairs are worth every penny. By the way, I bought the GL for around $40k. With the repairs, I am around $55k all in. Where are you going to get a $55k ish truck with the utility of the GL550?
Junior Member
Joined: Apr 2025
Posts: 17
Likes: 1
gl 550 x166
Idk i got mine 15 GL550 for 10k from Copart. Though I had to pay 5 more for shipping to Bulgaria + taxes. I changed sparks, coils, rotors, brakes, belt and pulleys all by myself, so I only paid the parts. I guess next in line would be the suspension and turbo cooling lines as I'm reaching that 100k milestone...
