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Mercedes-Benz GLS: X166 and X167 generations, engines, and trims
The Mercedes-Benz GLS is the largest and most luxurious Mercedes-Benz SUV with three rows of seats. We look at how the X166 and X167 generations differ, which engines are most common, how the trims vary, and what you need to check before buying a used GLS.
GLS in brief
The GLS name emerged in 2015–2016 when the GL model was updated. Mercedes-Benz calls it the 'S-Class of SUVs': it's a large, quiet, and comfortable vehicle that usually comes with seven seats and 4MATIC all-wheel drive.
In Lithuania, the GLS is often purchased as a large family or representative vehicle. The used market is dominated by diesel models, as they are significantly more economical than V8 petrol engines.
X166 vs X167 — what's the difference
The X166 generation GLS (2016–2019) is a refreshed GL with a new front end, a more modern interior, and most versions come with a 9-speed automatic transmission. The standard AIRMATIC air suspension ensures great comfort, but it becomes one of the most expensive parts to maintain as it ages.
The X167 generation (from 2019) is longer, more spacious in the third row, and features the MBUX multimedia system with two large screens. The 2023 updates include a new steering wheel, refreshed multimedia, and revised engine names.
If your budget allows, opt for the X167 generation — it's more modern and comfortable for third-row passengers. The X166 is cheaper, but most cars already have high mileage, and repairs can be costly.
Engines and transmissions
The X166 most commonly comes with the GLS 350d featuring a V6 diesel engine (around 258 hp). Petrol options include the GLS 400 (V6, around 333 hp), GLS 500 (V8, around 455 hp), and the Mercedes-AMG GLS 63 (around 585 hp).
The X167 offers diesel engines with six-cylinder in-line configurations: the 350d (around 286 hp), 400d (around 330 hp), and from 2023, the 450d. Petrol models like the GLS 450 and GLS 580 come with a 48V mild hybrid system called EQ Boost, while the sportiest options are the Mercedes-AMG GLS 63 and the luxurious Mercedes-Maybach GLS 600.
Almost all GLS models come with a 9-speed automatic transmission and 4MATIC all-wheel drive, making them well-suited for towing trailers.
What to check when buying a used GLS
Check the AIRMATIC air suspension: after overnight parking, the car shouldn't be sagging on one corner, and the compressor shouldn't run too long or too loudly. Suspension repairs are among the most expensive maintenance costs for this model.
For diesel cars, check the AdBlue system and the diesel particulate filter (DPF), and ensure the engine isn't leaking oil. For the X167, also check all electronic systems and multimedia features—they need up-to-date software.
The GLS is a heavy vehicle, so brakes, tyres, and suspension parts will wear out faster. Check the service history and technical inspection records for the ride, and inspect the body for repainted parts.
Trim levels
Names and equipment vary by market and year; we list the most common trims found in Europe.
Bazinė
X166, X167Even the base model comes with plenty of comfort features.
- Air suspension with AIRMATIC
- Most commonly, seven seats
- Often — leather seats and electrically adjustable third-row seats
AMG Line
X166, X167The most popular sporty trim.
- AMG-style bumpers and side skirts
- Often — 21-inch or larger wheels
- Sporty steering wheel and pedals
Mercedes-AMG GLS 63
X166, X167The sporty AMG version with a V8 engine.
- Around 585–612 hp V8 petrol engine
- AMG suspension and brakes
- Often — 22–23-inch wheels
Mercedes-Maybach GLS 600
X167The most luxurious version, designed for passenger transport.
- V8 petrol engine
- Often — two separate rear seats
- Especially luxurious interior trim
X167 generation trim comparison
| Bazinė | AMG Line | AMG GLS 63 | Maybach GLS 600 | |
|---|---|---|---|---|
| Who's it for? | Big families | Families and style | For speedy driving | Passenger comfort |
| Common wheels | 20–21 inch | 21–22 inch | 22–23 inch | 22–23 inch |
| Interior | 7 seats, leather trim | 7 seats, sportier trim | AMG sport seats | Often 4 seats, luxurious trim |
| Engine | Diesel 350d–450d, petrol 450 | Diesel 350d–450d, petrol 450, 580 | V8, around 612 hp | V8 petrol |
| Price in the used market (relatively) | Budget-friendly | Mid-range | Premium | Premium |
For most buyers, the best choice is the GLS 350d or 400d with AMG Line trim. The AMG GLS 63 and Maybach GLS 600 are worth considering only if running costs aren't a concern.
Pros
- Spacious interior with three rows of seats
- Very comfortable and quiet ride
- Powerful and relatively economical diesel engines
- Ideal for long journeys and towing trailers
Cons
- Expensive to maintain and repair, especially the air suspension
- Large — awkward in cities and tight parking spaces
- High costs for tyres, brakes, and insurance
Frequently asked questions
How does the GLS differ from the GLE?
The GLS is longer, roomier, and usually comes with seven seats, with the third row being spacious enough for adults. The GLE is more compact and affordable, so if you don't need the third row, it's often the more sensible choice.
Is the GLS's air suspension reliable?
The AIRMATIC suspension is very comfortable, but as it ages, the air springs and compressor can start to leak air. When buying an older or high-mileage GLS, it's worth budgeting for suspension repairs and getting it checked by a service before purchasing.
Which GLS engine is best when buying used?
For many buyers, the best diesel options are the X166 generation 350d or the X167 generation 350d and 400d. They consume significantly less fuel than the V8 petrol engines, and they have plenty of power for such a car.
Updated 2026-10-09 · Trim levels and equipment vary by market and model year — check the equipment of the specific car. · Translated automatically
