SL/R231: How reliable is the 2013-2016 SL550?
Thor
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Remember MB makes millions of engines world wide. These engines push the performance/efficiency envelope so MUST be maintained and fed proper fuel.
So we have reports of what? A dozen or two failures? How many people are happily running their M278’s and will never come to (or even know) an MB forum exists to complain? Most of these failures come from second hand owners, with unknown TRUE history, not just what’s on carfax.
Plenty of HIGH MILEAGE M278 litter the classified ads in Autotrader. Many with much more than 150k miles.
203k:
https://www.autotrader.com/cars-for-...ckType=listing
197k:
https://www.autotrader.com/cars-for-...ckType=listing
175k:
https://www.autotrader.com/cars-for-...ckType=listing
162k
https://www.autotrader.com/cars-for-...ckType=listing
There are many, many more listed! You can do a search nationwide, by highest mileage.
Forum member @Timo Schroeder has an early M278 with over 250k miles, I believe he’s original owner too.
Those that think the 2015+ M278’s are sleeved are sadly mistaken, MB just switched to iron to spray the cylinders instead of Silitec. Other manufacturers such as Ferrari have done this also in an effort to help prevent this type of failure. But, they still keep happening, as nothing will save an engine from detonation/pre-ignition damage. Even sleeved, engines just chew up the weakest part, which will now be the piston skirts made out of Aluminum.
As far as ABC goes that’s a personal choice. I’ve driven ALL the R231’s. ABC and non ABC, AMG etc.. . I worked for MB (and other MFG’ers ) as a tech, though before the R231 came out. Sure the R231’s ABC is more reliable than the R230, but as these cars age, parts availability will plague these systems. MB and other manufacturers are aggressively discontinuing parts at a much greater rate than seen ever before.

I used to flip cars when I was younger, but typically now keep my cars for over 20 years. So always look to K.I.S.S.
R231 will be the last SL I will probably own.
I’ve driven EVERY iteration of the R231, when properly tuned via tire pressure and tire compound, the non ABC car is less harsh than the AMG cars.
I would rate ride from softest to stiffest (not handling)
Non AMG SL with ABC - Non AMG SL with Springs and soft tires like Michelin Sports - Non AMG SL with Springs and run flats - SL63 non run flats - SL63 AMG run flats. Wheel size is also a factor, 18’s are softer than 19’s which are softer than 20’s. The larger the wheel the more critical tire choice and pressure becomes. It’s all a balance of what you’re looking for in a car. It’s nice to have options…

Good Luck.
Last edited by crconsulting; Jul 19, 2025 at 12:07 PM.
The Best of Mercedes & AMG
When the SL 400 was released, I believe back in 2013 or 2014, Car and Driver Magazine wrote an article on it based on their test, drive an inspection. They said it was the best handling and most spirited Mercedes they had ever driven. They really love that car. You can do an Internet search and find that very article it is still posted.
Last edited by docjoe; Jul 19, 2025 at 12:41 PM.




When the SL 400 was released, I believe back in 2013 or 2014, Car and Driver Magazine wrote an article on it based on their test, drive an inspection. They said it was the best handling and most spirited Mercedes they had ever driven. They really love that car. You can do an Internet search and find that very article it is still posted.
Remember MB makes millions of engines world wide. These engines push the performance/efficiency envelope so MUST be maintained and fed proper fuel.
So we have reports of what? A dozen or two failures? How many people are happily running their M278’s and will never come to (or even know) an MB forum exists to complain? Most of these failures come from second hand owners, with unknown TRUE history, not just what’s on carfax.
Plenty of HIGH MILEAGE M278 litter the classified ads in Autotrader. Many with much more than 150k miles.
203k:
https://www.autotrader.com/cars-for-...ckType=listing
197k:
https://www.autotrader.com/cars-for-...ckType=listing
175k:
https://www.autotrader.com/cars-for-...ckType=listing
162k
https://www.autotrader.com/cars-for-...ckType=listing
There are many, many more listed! You can do a search nationwide, by highest mileage.
Forum member @Timo Schroeder has an early M278 with over 250k miles, I believe he’s original owner too.
Those that think the 2015+ M278’s are sleeved are sadly mistaken, MB just switched to iron to spray the cylinders instead of Silitec. Other manufacturers such as Ferrari have done this also in an effort to help prevent this type of failure. But, they still keep happening, as nothing will save an engine from detonation/pre-ignition damage. Even sleeved, engines just chew up the weakest part, which will now be the piston skirts made out of Aluminum.
As far as ABC goes that’s a personal choice. I’ve driven ALL the R231’s. ABC and non ABC, AMG etc.. . I worked for MB (and other MFG’ers ) as a tech, though before the R231 came out. Sure the R231’s ABC is more reliable than the R230, but as these cars age, parts availability will plague these systems. MB and other manufacturers are aggressively discontinuing parts at a much greater rate than seen ever before.

I used to flip cars when I was younger, but typically now keep my cars for over 20 years. So always look to K.I.S.S.
R231 will be the last SL I will probably own.
I’ve driven EVERY iteration of the R231, when properly tuned via tire pressure and tire compound, the non ABC car is less harsh than the AMG cars.
I would rate ride from softest to stiffest (not handling)
Non AMG SL with ABC - Non AMG SL with Springs and soft tires like Michelin Sports - Non AMG SL with Springs and run flats - SL63 non run flats - SL63 AMG run flats. Wheel size is also a factor, 18’s are softer than 19’s which are softer than 20’s. The larger the wheel the more critical tire choice and pressure becomes. It’s all a balance of what you’re looking for in a car. It’s nice to have options…

Good Luck.
When the SL 400 was released, I believe back in 2013 or 2014, Car and Driver Magazine wrote an article on it based on their test, drive an inspection. They said it was the best handling and most spirited Mercedes they had ever driven. They really love that car. You can do an Internet search and find that very article it is still posted.
Best part is you don't have that butt ugly nose of the R231. They really screwed it up trying to meet the euro pedestrian impact regs imho.
;-)




No matter which iteration, you’re getting the last Vario Roof MB will probably make. They all drive fantastic! Like all things, it’s about your personal expectations. That’s why it’s nice to have choices
.Overall while still pretty complex, it’s still toned down tech wise to make the car fairly reliable for owners willing to keep them long term. Parts availability, for me, is always a problem for complex older cars (with low production numbers). It’s the little things that usually get you

For what it’s worth, My ‘13 SL550 (47k) has been easily as reliable as my R129 SL600 was, if not more so. Doesn’t even compare power wise.
So hopefully, long term R231 will continue it’s reliability. We’ll see…
If you’re just going to drive it for 5 years, pick the lowest mileage, best condition model you choose and enjoy. After some typical used car “fixes”. Chances are it will be a great car.
All great convertible’s, you’ll have lots of fun.
Let us know.
Last edited by crconsulting; Jul 19, 2025 at 04:19 PM.
I just feel if I'm going to keep the car for a long time (this would be just a fun third car) that I'd be wise to stay away from ABC.
Thor
Correct me if wrong, but I believe ABC is standard on the SL63 (which is why I was avoiding it)....




I personally use Autotrader too.(see link below) I ‘d take my time to find the right car locally. Not sure I looked 15 mo, but I looked for a while. I wasn't in a hurry and wanted to buy locally, so I could check them with XENTRY, on the cars I was interested in.
Run Carfax AND Autocheck. If you can get the VMI from MB that’s also worth looking at…
https://www.autotrader.com/cars-for-...2013&zip=94559
Good Luck
Last edited by crconsulting; Jul 20, 2025 at 10:12 AM.




I just feel if I'm going to keep the car for a long time (this would be just a fun third car) that I'd be wise to stay away from ABC.
I skipped that model all together (R230). But to be fair, the R231’s ABC is much improved over the R230’s, especially the early models. ADSII on the SL600 (R129) was OK, but parts availability started being an issue. Which is typical as these cars age. (I believe for the R231 parts availability may become worse). In the time I owned it, close to 20 years, I did the nitrogen spheres on all four corners three times (R129). Now that I’m older, I really don’t want to crawl under a car unless I have to.
Once you get the right tires and pressure combo the ride is excellent, The non ABC cars get a little more body roll, especially the V8, but it’s pretty mild. It’s a 4000lb Grand Tourer, not a race car. Problem with test driving cars, tire pressure, rubber age, heat cycles and tire compounds are out of your control. You can definitely feel old tires on larger diameter wheels. They are so much harsher.
Test drive a few models, see what you think. That’s what’s important….
Good Luck
Last edited by crconsulting; Jul 20, 2025 at 10:17 AM.
I skipped that model all together (R230). But to be fair, the R231’s ABC is much improved over the R230’s, especially the early models. ADSII on the SL600 (R129) was OK, but parts availability started being an issue. Which is typical as these cars age. (I believe for the R231 parts availability may become worse). In the time I owned it, close to 20 years, I did the nitrogen spheres on all four corners three times (R129). Now that I’m older, I really don’t want to crawl under a car unless I have to.
Once you get the right tires and pressure combo the ride is excellent, The non ABC cars get a little more body roll, especially the V8, but it’s pretty mild. It’s a 4000lb Grand Tourer, not a race car. Problem with test driving cars, tire pressure, rubber age, heat cycles and tire compounds are out of your control. You can definitely feel old tires on larger diameter wheels. They are so much harsher.
Test drive a few models, see what you think. That’s what’s important….
Good Luck






