What Is the Mercedes-Benz GLS?
The Mercedes-Benz GLS-Class is the brand’s flagship full-size luxury SUV, offering three rows of seating for up to seven passengers and up to 94 cubic feet of cargo space. It sits at the very top of the Mercedes-Benz SUV lineup and competes directly against rivals like the BMW X7, Cadillac Escalade, Lincoln Navigator, Lexus LX, and Audi Q7.
The name “GLS” follows Mercedes-Benz’s naming convention: G for the SUV family, L for long (full-size), and S for the S-Class level of luxury. Think of it as an S-Class on steroids — combining the comfort of the world-class S-Class sedan with a modicum of off-road capability borrowed from the legendary G-Class.
Prior to 2016, the vehicle was sold as the GL-Class. The nameplate was updated to GLS in the 2016 model year to align with Mercedes’ revised naming strategy and emphasize its premium positioning.
🏆 Quick Definition
The Mercedes-Benz GLS is a full-size, three-row luxury SUV with 6–7 passenger seating, available in GLS 450 (inline-6 turbo, 375 hp), GLS 580 (V8 turbo, 510 hp), and AMG GLS 63 (V8 biturbo, 603 hp) variants. It is designed to blend the comfort of a luxury sedan with practical family-sized space and light off-road capability.
Mercedes-Benz GLS History & Generations
Understanding the GLS’s model history is essential before making a purchase decision. The vehicle evolved significantly across two main generations, each with distinct characteristics, engines, technology, and reliability profiles.
1st Gen GL-Class (2006–2012): The Foundation
Mercedes introduced the full-size GL-Class to compete against the Cadillac Escalade and Lincoln Navigator. It featured a unibody construction that improved maneuverability compared to rivals. Engine options included a 5.5L V8 (GL550) and a 3.0L diesel V6 (GL320 CDI). Despite some early reliability concerns in 2007, the 2008 and 2011 models emerged as the most dependable from this generation.
2nd Gen GL-Class (2013–2016): Refined & Polished
A significant redesign brought more luxury, improved engines, and better technology. The 7-speed automatic transmission was standardized across all variants. The GL63 AMG offered sports-car performance in an SUV body. The 2016 model was the best from this phase, refined to near-perfection before the nameplate change.
GLS Nameplate Begins (2017–2019): Transition Years
Mercedes renamed the GL-Class to GLS-Class in 2017, applying a refresh to the existing second-gen platform. The interior and exterior were updated, but the underlying architecture remained the same. The 2017 model proved problematic (see Worst Years), while 2018–2019 were steadily improving.
3rd Generation GLS (2020–Present): Modern Luxury Redefined
A ground-up redesign on a new platform stretched the wheelbase and introduced cutting-edge technology including MBUX infotainment, a 48V mild-hybrid system (EQ Boost), air suspension, and optional E-Active Body Control. Engine options: GLS 450 (inline-6 turbo, 375 hp) and GLS 580 (V8 biturbo, 510 hp). The 2020–2021 models suffered from early-production 48V battery and electrical issues, while 2022–2024 show significantly improved reliability.
Mercedes-Benz GLS Best Years to Buy
Based on NHTSA complaint data, Consumer Reports reliability scores, automotive expert reviews, and verified owner feedback, the following model years represent the best the GLS has to offer in terms of reliability, value, and overall satisfaction.
Best New Buy — Top Pick
A design refresh added a new grille, updated LED taillights, modern steering wheel, and fresh interior color options. The GLS 450’s turbocharged inline-6 (375 hp) is the most reliable engine in the lineup per NHTSA complaint density data. Software and hardware bugs from 2020–2021 have been fully addressed. Best technology, best safety features, best warranty coverage.
Excellent Reliability, Mature Tech
The 2023 GLS benefits from three full years of production refinement since the third-gen launch. 48V system issues are largely resolved, software is mature, and customer satisfaction scores climbed noticeably. The AMG GLS 63’s biturbo V8 producing 603 hp and 627 lb-ft of torque makes this the performance choice too.
Sweet Spot — Value + Reliability
The 2022 model year is the ideal used-car sweet spot: significant depreciation from MSRP, yet far more reliable than 2020–2021. Electrical system improvements were finalized. Full MBUX infotainment, air suspension, and modern safety suite make this feel thoroughly contemporary.
Best Pre-Rename Buy (Budget Friendly)
The final year of the second-generation platform before the GLS rename, the 2016 GL/GLS offers excellent build quality, a well-sorted 7-speed transmission, proven powertrain, and no major software complications. Excellent for buyers on a tighter budget who still want true Mercedes luxury with low cost-per-mile reliability.
Best First-Gen GL — Classic Reliability
One of the most praised model years in the GL/GLS family. Consumer Reports highlighted the 2011 GL as particularly dependable, with few reported drivetrain issues. The diesel GL350 BlueTEC from this era is especially beloved for its fuel economy and longevity — some have exceeded 200,000 miles.
Most Reliable First-Gen GL
After Mercedes resolved the first-year quirks of the 2007 GL450/550, the 2008 model emerged as the standout in the inaugural generation. Solid build quality, dependable V8 engine, and far fewer electrical problems than later years. A great budget buy for buyers who do not need the latest technology.
💡 Pro Tip: When shopping for a used GLS, prioritize the GLS 450 (inline-6 turbocharged engine) over the GLS 580 V8. Per NHTSA complaint density data, the 3L inline-6 has significantly fewer reported issues and lower maintenance costs, making it the most reliable engine option in the 2020+ generation.
Mercedes-Benz GLS Worst Years to Avoid
These model years have generated the most complaints, recalls, and owner frustration. While no GLS is irredeemably bad, these specific years carry higher-than-average risk and should be approached with caution — or avoided altogether if you prioritize reliability.
The 2017 Mercedes-Benz GLS is the most complained-about model year, with multiple NHTSA reports of vehicles catching fire spontaneously — attributed to electrical, engine, and transmission failures. Some fires caused total vehicle loss and damaged surrounding property including garages and homes.
Worst Year Overall — Avoid
The highest volume of serious complaints in GLS history. Issues include spontaneous fires, major electrical failures, transmission problems, and engine malfunctions. Multiple NHTSA investigations linked fire incidents to a broad range of root causes. The most problematic GLS ever produced — stay away.
Highest Recall Count — 12 Recalls
The 2021 GLS was recalled 12 times by NHTSA — an extraordinary number for a single model year. Major issues include a 48V battery ground connection fire risk (a loose bolt under the front passenger seat caused overheating), third-row seatback locks that could fail in a crash, and multiple fuel system and engine stall issues.
First-Year New Platform Issues
As a ground-up redesign, the 2020 GLS was plagued by typical first-year bugs. Owners reported 48V battery system malfunctions causing sudden power loss and engine stalling. Of 11 NHTSA complaints on record, 7 were electrical and 6 were fuel/propulsion system issues. The 48V mild-hybrid system was fundamentally flawed at launch.
Carry-Over Problems from 2017
While not as severe as 2017, the 2018 GLS shared the same platform with many unresolved electrical gremlins. Transmission software issues, infotainment glitches, and air suspension failures were disproportionately reported in this model year. Acceptable only if priced significantly below market with a full inspection.
Improving but Not Yet Resolved
The 2019 model saw improvements but still carried over some of the 2017–2018 platform’s persistent issues. AC drain hose failures (causing interior water leaks), oil pump solenoid problems, and occasional transmission shudder remained concerns. Better than 2017–2018 but not a clean bill of health.
First-Year First-Gen Problems
As the debut year of the GL-Class family, the 2007 model had typical first-year bugs including transmission rough shifting, suspension quirks, and electrical issues. Most were resolved by 2008 but 2007 vehicles present higher-than-average risk on the used market decades later.
GLS Reliability Comparison by Year
| Year | Generation | Engine | Reliability | Key Issue | Verdict |
|---|---|---|---|---|---|
| 2024 | 3rd Gen GLS | Inline-6 / V8 | Excellent | None significant | ✅ Buy |
| 2023 | 3rd Gen GLS | Inline-6 / V8 | Very Good | Minor software | ✅ Buy |
| 2022 | 3rd Gen GLS | Inline-6 / V8 | Good | 48V improved | ✅ Buy |
| 2021 | 3rd Gen GLS | Inline-6 / V8 | Poor | 12 NHTSA recalls | ❌ Avoid |
| 2020 | 3rd Gen GLS | Inline-6 / V8 | Below Avg | 48V battery issues | ❌ Avoid |
| 2019 | 1st Gen GLS | V6 / V8 | Average | AC drain, oil pump | ⚠️ Caution |
| 2018 | 1st Gen GLS | V6 / V8 | Below Avg | Electrical, suspension | ⚠️ Caution |
| 2017 | 1st Gen GLS | V6 / V8 | Very Poor | Fire risk, electrical | ❌ Avoid |
| 2016 | 2nd Gen GL | V6 / V8 | Very Good | None major | ✅ Buy |
| 2015 | 2nd Gen GL | V6 / V8 | Good | Minor software | ✅ Consider |
| 2013–14 | 2nd Gen GL | V6 / V8 | Average | Transmission quirks | ⚠️ Inspect |
| 2011 | 1st Gen GL | V8 / Diesel | Very Good | Age-related wear | ✅ Buy (budget) |
| 2008 | 1st Gen GL | V8 | Good | Age-related wear | ✅ Buy (budget) |
| 2007 | 1st Gen GL | V8 | Below Avg | First-year bugs | ❌ Avoid |
Most Common Mercedes-Benz GLS Problems
Whether you own a GLS or are considering buying one, understanding the most frequently reported problems is critical. Here is a comprehensive breakdown of recurring issues by system, based on NHTSA complaint data (92 complaints for 2020–2025 models alone), technical service bulletins, and owner forums.
⚡ 1. 48-Volt Battery & Electrical System
The single most reported problem in the 2020–2022 GLS is the 48V mild-hybrid (EQ Boost) battery system. Symptoms include sudden power loss, engine stalling without warning, and failure to accelerate. A manufacturing defect caused the ground cable bolt for the 48V connection under the front passenger seat to be inadequately secured, leading to overheating and fire risk. Mercedes issued multiple recalls to address this. Affected models: 2019–2023 GLS 450, GLS 580, AMG GLS 63, Maybach GLS 600.
🔧 2. Transmission Downshift / Engine Stall
The transmission control unit software in 2020–2023 GLS 450 models may fail to fully complete a downshift from 7th to 6th gear during light braking. This causes the engine to stall with no warning — a dangerous situation in traffic. Mercedes issued a recall in 2024 requiring dealers to update the transmission control unit software free of charge. Over 105,000 units were potentially affected.
🛞 3. Air Suspension Failures
The AIRMATIC air suspension — standard on many GLS trims — is expensive to repair when it fails. Compressor failures, leaking air struts, and valve block failures are all common, particularly on 2013–2019 models with higher mileage. Replacement costs range from $1,500 to $4,000+ per axle at a dealership. Always check suspension behavior when test driving a used GLS.
🛢️ 4. Engine Oil Consumption (M157 V8)
The M157 biturbo V8 engine (used in GL 63 AMG and GLS 63) is known to consume several quarts of oil between 10,000-mile oil change intervals. This is not necessarily a defect but requires owners to monitor oil levels actively. Using the correct oil (Mobile 1 0W-40) and a Mann or OEM Mercedes fleece filter helps minimize consumption.
💦 5. AC Drain & Water Leak Issues
A recall covered 2020–2023 GLS models where improperly installed AC drain hoses allowed condensation to pool and eventually leak into the interior — soaking carpets and potentially damaging electrical components. Dealers fixed this by reinspecting and reinstalling drain hoses free of charge.
🔥 6. Spontaneous Fires (2017 Models)
The 2017 GLS uniquely stands out for owner reports of vehicles catching fire without warning — while parked, at low speeds, and during normal operation. The fires were attributed to a range of causes including electrical short circuits, engine compartment heat, and transmission fluid issues. This remains the single most alarming pattern in GLS complaint history.
Pros & Cons of the Mercedes-Benz GLS
✅ Advantages
- 🏆 Class-leading luxury interior with top-quality materials and craftsmanship
- 👨👩👧👦 True 7-passenger seating with usable third row for adults
- ⚡ Powerful engine options including the 603 hp AMG GLS 63
- 💻 MBUX infotainment with dual 12.3-inch screens (2020+)
- 🛤️ Outstanding ride quality with standard air suspension
- 🔒 Comprehensive suite of active safety features
- 📦 Up to 94 cubic feet cargo space (1st gen)
- 💰 Strong depreciation = great value on used market
- 🐎 Available with Mercedes-Maybach GLS 600 ultra-luxury trim
❌ Disadvantages
- 💸 Very high purchase price (starts at ~$90,000 new)
- 🔧 Expensive maintenance and repair costs
- ⚡ 48V electrical system can be costly to diagnose and repair
- 💨 Poor fuel economy — ~19 mpg combined for GLS 450
- 🛠️ Air suspension repairs range from $1,500–$4,000+
- 📉 Reliability lags behind Japanese and German rivals
- 🏋️ Very large and heavy — difficult to park in urban settings
- 🔋 2020–2021 48V battery issues create lingering concerns
Is the Mercedes-Benz GLS Safe?
Safety is a top priority for most buyers of a family-oriented luxury SUV, and the GLS delivers on several fronts — though some years have significant safety concerns.
Standard Active Safety Features (2020+)
The current-generation GLS comes equipped as standard with Forward Collision Warning with Automatic Emergency Braking, Lane Departure Warning, Electronic Stability Control, Adaptive Cruise Control with Stop & Go, Active Blind Spot Monitoring, and a 360-degree camera system. These features place it among the safest full-size SUVs in its class.
NHTSA & Recall Concerns
Despite its safety features, the GLS has accumulated notable recall activity. The 2021 GLS alone was recalled 12 times. Recall highlights include:
- Fire Risk (48V Ground Connection): Affecting 2019–2024 models — a loose bolt under the passenger seat can cause the 48V ground connection to overheat and potentially ignite.
- Engine Stall (Transmission Software): Affecting 2020–2023 GLS 450 and GLE 450 — over 105,000 vehicles subject to stalling at highway speeds.
- Third-Row Seatback Locks: Affecting 2020–2022 GLS models — seatback locks may fail to hold occupants properly in a crash.
- AC Drain Hose: Allowing water ingress into the cabin, potentially contacting electrical components.
✔️ Safety Verdict: The 2022, 2023, and 2024 GLS are the safest choices. All open recalls have been addressed, safety technology is at its most advanced, and the 48V system vulnerabilities have been resolved through dealer service. Always check NHTSA.gov for open recalls on any specific VIN before purchase.
Mercedes-Benz GLS Types, Trims & Variants
The Standard Choice
3.0L turbocharged inline-6 producing 375 hp and 369 lb-ft of torque. 9-speed automatic transmission. Most reliable engine in the lineup. Recommended for everyday family use. Standard air suspension, MBUX, AWD (4MATIC).
The Power Upgrade
4.0L twin-turbocharged V8 with 510 hp and 568 lb-ft of torque. Elevated performance with the same luxury appointments. Higher fuel costs and marginally more reported issues than the inline-6, but significantly more power for towing and highway driving.
The Performance SUV
Handcrafted 4.0L twin-turbo V8 — 603 hp, 627 lb-ft of torque. AMG-tuned suspension, exhaust, and brakes. 0–60 mph in ~4.2 seconds. Standard AMG ACTIVE RIDE CONTROL. For those who want a supercar-pace daily driver that seats 7.
Ultra-Luxury Four-Seater
The pinnacle of Mercedes luxury in an SUV body. 4.0L V8 with 558 hp, first-class rear executive seats with massage, fold-out tables, champagne flutes, and a starlight headliner option. Configured for 4-passenger luxury over maximum utility.
Diesel Variant (2006–2016)
Available in first and second generation only. 3.0L diesel V6 with exceptional torque and fuel economy (~25+ mpg highway). Extremely popular in Europe. Some first-gen diesel models have surpassed 200,000 miles with proper maintenance. Not sold in some US states.
First-Gen Performance (2013–2015)
The original performance variant powered by a 5.5L biturbo V8 producing 550 hp. A classic muscle car in SUV clothing. Many owners have exceeded 130,000+ miles. Good long-term reliability when properly maintained, though oil consumption monitoring is essential.
How to Buy a Used Mercedes-Benz GLS
The average listing price for a used GLS across all model years is approximately $54,000 — a significant value relative to the $90,000+ new price. Follow these steps to find the best deal while minimizing risk.
Step 1: Choose the Right Model Year
Based on this guide, target 2022–2024 for the best blend of modern technology and resolved reliability issues. If budget is a concern, 2016 represents exceptional value in the pre-GLS era. Always avoid 2017, 2020, and 2021 unless the price deeply reflects the risk.
Step 2: Check NHTSA for Open Recalls
Visit NHTSA.gov and enter the VIN of any vehicle you are considering. Confirm that all open recalls — especially the 48V ground connection fire recall and the transmission stall recall — have been completed by an authorized Mercedes-Benz dealer. This is non-negotiable for 2019–2023 models.
Step 3: Get a Pre-Purchase Inspection
Always commission an independent pre-purchase inspection from a certified Mercedes-Benz technician (not a generic mechanic). Key items to check: AIRMATIC air suspension compressor, 48V battery health, transmission behavior at highway speeds, all recall service completion, and any stored diagnostic fault codes.
Step 4: Check Maintenance History
A complete service history from a Mercedes-Benz dealership is the gold standard. Look for: 10,000-mile oil changes using approved oils (Mobile 1 0W-40 for AMG V8 models), air filter replacements, and transmission service records. Lack of documented service history is a red flag on a GLS.
Step 5: Negotiate Based on Known Issues
If you find a 2020 or 2022 GLS and all recalls have been completed, use the history of known issues as negotiating leverage. Budget at least $2,000–$5,000 for potential upcoming maintenance on any used GLS with 50,000+ miles, including air suspension service, brake fluid flush, and spark plugs.
🎯 Best Value Used GLS Advice
A 2022 GLS 450 with 25,000–40,000 miles hits the sweet spot: significant depreciation (often $20,000–$30,000 off MSRP), modern technology, the most reliable engine variant, and resolved first-generation issues from the 2020 launch. Confirm all recalls completed and get an independent inspection. This represents the single best value proposition in the used GLS market today.
Frequently Asked Questions
The 2024 GLS is the best model year overall, offering a refreshed design, the most advanced technology, and the fewest reported issues. For used buyers, the 2022 and 2023 models offer the best blend of modern features, resolved 48V system issues, and reasonable depreciated pricing. For budget shoppers, the 2016 GL-Class remains an excellent value.
The 2017 Mercedes-Benz GLS is widely considered the worst model year. It generated the most NHTSA complaints, including disturbing reports of vehicles catching fire spontaneously. The 2021 GLS also holds a poor record with 12 NHTSA recalls, including critical fire risk and seatback failure issues. Avoid both.
The GLS has average to below-average reliability for the luxury SUV segment when compared against class leaders like the Lexus LX or Land Cruiser. However, reliability has improved significantly in 2022–2024 models. Keeping up with scheduled maintenance, addressing all recalls promptly, and monitoring the oil level in V8 AMG models are essential for long-term dependability.
With proper and regular maintenance, a Mercedes-Benz GLS can realistically reach 150,000 to 200,000 miles. Some owners of well-maintained diesel and V8 models have reported exceeding 200,000 miles. The key factors are: using correct factory-spec fluids, completing all recalls on time, and addressing minor issues before they become major ones.
The most common GLS problems include: (1) 48V battery and electrical system failures (2020–2022), (2) transmission stalling during downshift (2020–2023), (3) AIRMATIC air suspension compressor failure (all generations), (4) engine oil consumption in AMG V8 models, and (5) AC drain hose leaks (2020–2023). Most of these have been addressed through NHTSA recalls and TSBs.
Yes — the GLS is one of the best family luxury SUVs on the market. It offers genuine 7-passenger seating with an accessible third row, up to 94 cubic feet of cargo space with all seats folded, comprehensive safety features, and the highest level of comfort across all three rows. The GLS 450 is the recommended family choice for its reliability advantage over the V8.
They are the same vehicle. Mercedes-Benz renamed the GL-Class to GLS-Class in 2016 as part of a broader naming convention overhaul across the entire lineup. The “S” was added to emphasize that this is the S-Class-level of luxury within the SUV family. The underlying platform of the first GLS (2017) was essentially the same as the 2013–2016 GL-Class.
Yes, for the right model year. The average used GLS lists at approximately $54,000 versus a $90,000+ new MSRP — a substantial depreciation benefit. Focus on 2022–2024 models with documented service history, all recalls completed, and a clean pre-purchase inspection. Avoid 2017 and 2020–2021 regardless of price.
Annual maintenance costs for a Mercedes-Benz GLS typically range from $1,200 to $2,500 per year for routine service. Budget for higher costs in years when air suspension service, tire replacement (large expensive tires), brake replacement, and spark plug changes are due. Unexpected repairs — particularly to the 48V electrical system or air suspension — can cost $2,000–$6,000. An extended warranty or certified pre-owned purchase is strongly recommended.
You should avoid 2017, 2020, and 2021 as primary targets. The 2017 has the worst safety record (fire incidents). The 2020 launched the new platform with immature 48V technology. The 2021 was recalled 12 times. Additionally, 2007 (first-year GL) and 2018 (electrical carry-over issues) should be approached with caution and only at deeply discounted prices with full independent inspections.
