Mercedes-Benz GLS Buying Guide for Southern California
The full-size Mercedes-Benz SUV — genuine three-row seating for adults and the running costs that come with a vehicle this size.
Written and reviewed by Nicholas Velez, Founder, Car Dogs · Updated August 14, 2026
The GLS is Mercedes-Benz's largest SUV, built to seat seven or eight with a third row that can actually accommodate adults, not just kids on short trips. It's the SUV to consider if the GLE's third row feels too tight, but it comes with correspondingly higher running costs.
Who it fits
Larger families or households that regularly carry six or more people, including adults in the third row, and want that capability without giving up Mercedes-level comfort and features.
If your third-row use is occasional and mostly kids, the smaller and less expensive GLE is worth cross-shopping first.
Trim, engine and 4MATIC ladder
- The GLS lineup has included six-cylinder, V8 and AMG-tuned performance variants — confirm exact availability on the specific model year you're considering.
- 4MATIC all-wheel drive is standard on the GLS, appropriate for a vehicle this size and commonly used for towing.
- Air suspension is standard or near-standard on the GLS given its size and weight, which is part of what makes it ride comfortably despite being a large three-row SUV.
What it competes with
Cross-shop candidates include the BMW X7, Audi Q8 (two-row) or Q7 (three-row), Cadillac Escalade and Land Rover Range Rover. Third-row comfort, towing capability and interior tech are the usual deciding factors.
Ownership costs after the factory warranty
- This is among the priciest Mercedes SUVs to maintain out of warranty, given its size, standard air suspension and available AWD/towing hardware — budget accordingly and research independent Mercedes-specialist shops in the LA area ahead of time.
- Air suspension repairs (springs, compressor, valve block) can be a significant expense as the vehicle ages; a pre-purchase inspection that specifically tests suspension function is essential on any used GLS.
- Run-flat or large-diameter tires common on this model are expensive to replace and typically not repairable.
- Brake and tire wear scale with the vehicle's substantial size and weight, meaning a shorter interval and higher per-service cost than smaller SUVs in the lineup.
Lease vs. finance and used/CPO inspection notes
Leasing is a common way to access a new GLS while staying under warranty for its full ownership term, given how costly out-of-warranty repairs can be on this model. Buying used can work well if you get a thorough independent inspection and factor realistic repair costs into your decision.
On a used or CPO GLS, test the third row's fold-and-latch mechanism, thoroughly test air suspension operation, confirm complete service history, and have an independent shop inspect for fluid leaks, towing-hitch wiring condition, and any electronics issues common on higher-mileage large SUVs.
The short version
The GLS delivers genuine adult-usable third-row seating, but it's also the priciest Mercedes SUV to run out of warranty — budget seriously and get a thorough inspection on any used example.
Common questions
- Can adults actually sit in the GLS third row?
- Yes, more comfortably than in the GLE or GLB. It's still tighter than the second row, but it's genuinely usable for adults on real trips, not just short hops.
- Is the GLS expensive to maintain?
- It's among the pricier Mercedes SUVs to run out of warranty, largely due to its standard air suspension and size. Research independent specialist shops in advance and budget realistically.
- How does the GLS compare to the GLE?
- The GLS is larger with more usable third-row space and generally higher capability, at a corresponding increase in purchase price and running costs. The GLE is the better fit if your third-row use is occasional.
- What should I check on a used GLS?
- Third-row function, thorough air suspension testing, full service history, and an independent inspection for fluid leaks and towing-related wear.
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