2018 Mercedes-Benz Gls Reliability ReportCommon Problems, Repair Costs & Expert Verdict
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Quick Facts · 2018 Mercedes-Benz Gls
- No active NHTSA safety recalls on record — a clean recall slate for the 2018 model year.
- Scores 6 points below the strongest nearby year — the 2017 Mercedes-Benz Gls earns a 78.
- The system most likely to surface first: airmatic air suspension system (major severity).
The 2018 Mercedes-Benz Gls at a glance
- Is the 2018 Mercedes-Benz Gls reliable?
- Autojunket rates the 2018 Mercedes-Benz Gls 72/100 (grade C-), categorized as moderate risk. A powerhouse of luxury and capability, but prepare your wallet for its intricate and often expensive maintenance needs.
- Should I buy a used 2018 Mercedes-Benz Gls?
- Autojunket recommends reading the full reliability report before buying a 2018 Mercedes-Benz Gls. The 2018 Mercedes-Benz GLS is an incredibly appealing luxury SUV, but it demands a knowledgeable owner and a substantial budget for maintenance and potential repairs. If you can accept and plan for these higher running costs, the GLS can be a rewarding ownership experience; otherwise, look elsewhere. Its known weak…
- Which Mercedes-Benz Gls years are the most reliable?
- Best model years to buy: 2019 (minor refinements), and later models after the X167 generation update if budget allows, as some issues were addressed.. Years to avoid: No specific years to outright avoid within the X166 generation, but earlier models (2013-2016 GL-Class) had more pronounced AIRMATIC and V8 engine issues..
- What are the most common problems with the 2018 Mercedes-Benz Gls?
- The top failure points on the 2018 Mercedes-Benz Gls are AIRMATIC Air Suspension System (typically around 60,000-100,000 miles), Electrical System & Modules (typically around 50,000-90,000 miles), Engine Oil Leaks & PCV System (typically around 70,000-110,000 miles). Autojunket's full report includes repair-cost ranges and inspection checklists for each.
- At what mileage do problems start on the 2018 Mercedes-Benz Gls?
- The first major mileage danger zone for the 2018 Mercedes-Benz Gls is around 30,000. Low Risk Zone — At this mileage, the GLS is still relatively new, and most issues would be covered under the original warranty. Focus is on routine maintenance and ensuring all software updates are applied.
Every answer is generated from real repair, recall, and ownership data — full breakdown in the report.
Read the full free reportShould You Buy the 2018 Mercedes-Benz Gls?
The 2018 Mercedes-Benz GLS is a luxurious and capable full-size SUV that offers impressive comfort and performance, but its complex engineering brings a significant risk of expensive repairs as it ages. While it provides an opulent experience, prospective owners must budget generously for potential air suspension and electrical system issues to truly enjoy this vehicle without financial surprises.
The 2018 Mercedes-Benz GLS is an incredibly appealing luxury SUV, but it demands a knowledgeable owner and a substantial budget for maintenance and potential repairs. If you can accept and plan for these higher running costs, the GLS can be a rewarding ownership experience; otherwise, look elsewhere. Its known weak…
Best Model Years
2019 (minor refinements), and later models after the X167 generation update if budget allows, as some issues were addressed.
Years to Avoid
No specific years to outright avoid within the X166 generation, but earlier models (2013-2016 GL-Class) had more pronounced AIRMATIC and V8 engine issues.
Biggest Strengths
- Robust V8 engine performance (GLS 550)
- Luxurious and comfortable interior ride
- Strong body structure and excellent safety features
Top Risk Areas
The systems that tend to fail first on the 2018 Mercedes-Benz Gls, with the typical mileage window when each becomes a concern. Detailed repair-cost ranges and exact what-to-check inspection notes are in the full report.
The air springs, compressor, valve block, and ride height sensors are notorious failure points. Leaks in the airbags or compressor failure lead to a 'saggy' suspension and inability to maintain ride height, drastically impacting ride qua…
Mercedes' complex electrical architecture is prone to various issues including parasitic battery drains, sensor failures (e.g., NOx, speed), infotainment glitches, and control module (ECM, TCU, SAM units) malfunctions, often requiring co…
Particularly on the V8 (M278) and less so on the V6 (M276) engines, oil leaks from the front timing cover, oil filter housing, and valve cover gaskets are common. PCV (Positive Crankcase Ventilation) valve failures can also lead to exces…
2018 Mercedes-Benz Gls Mileage Danger Zones
The mileage windows when the 2018 Mercedes-Benz Gls most commonly needs attention. Plan ahead, budget accordingly, and inspect before you cross each threshold.
Low Risk Zone
At this mileage, the GLS is still relatively new, and most issues would be covered under the original warranty. Focus is on routine maintenance and ensuring all software updates are applied.
Maintenance Zone
This mileage often coincides with major service intervals (e.g., spark plugs, transmission fluid). Air suspension components might start showing early signs of wear, such as increased compressor run time or minor height discrepancies.
Elevated Risk Zone
Expect age-related failures in the air suspension system, requiring significant investment. More complex electrical issues and engine component wear, like timing chain components on V8s, become a concern.
High Risk Zone
Beyond 100k miles, the GLS will likely require substantial repairs to maintain its luxury experience. Multiple air suspension components, comprehensive electrical diagnostics, and potential engine rebuilds or major component replacements…
2018 Mercedes-Benz Gls Ownership Cost Outlook
What it typically costs to keep the 2018 Mercedes-Benz Gls on the road. Full 5-year cost-of-ownership projection and major-failure-risk forecast are in the report.
Annual Maintenance
$800-1,200
Moderate Repairs
$1,500-3,000 occasionally (e.g., air strut, electrical module)
How Long Does the 2018 Mercedes-Benz Gls Last?
Focus on well-documented service history. Look for a GLS with lower mileage (under 60,000) for a safer bet, but be prepared for major expenses starting around 70,000 miles regardless.
What 2018 Mercedes-Benz Gls Owners Actually Say
What Owners Love
- Exceptional ride comfort and composure on various road surfaces.
- Powerful engine options providing effortless acceleration.
- Luxurious interior with high-quality materials and craftsmanship.
- Spacious third-row seating, making it a true seven-seater.
Common Frustrations
- Very high cost of repairs and parts, particularly for the air suspension.
- Frequent electrical glitches, including infotainment and sensor warnings.
- Significant depreciation, making used values attractive but ongoing costs high.
- Fuel economy is poor, especially with the V8 engines.
Who Should Buy the 2018 Mercedes-Benz Gls?
Best For
- Luxury buyers seeking maximum comfort and prestige for long road trips.
- Families needing genuine three-row seating without sacrificing opulence.
- Individuals who are comfortable with high maintenance costs and dealership service.
Not Ideal For
- Budget-conscious buyers looking for low long-term ownership costs.
- Owners who prefer DIY maintenance or rely on independent mechanics unfamiliar with Mercedes-Benz.
How the 2018 Mercedes-Benz Gls Compares to Rivals
The GLS offers a superior blend of luxury, performance, and advanced technology compared to many peers, but it comes with higher maintenance and repair costs than its Japanese rivals, sitting closer to other German luxury SUVs in terms of potential repair bills.
More Reliable Than
- Land Rover Range Rover (older generations)
- Infiniti QX80 (overall interior tech)
Comparable To
- BMW X7 (Fewer air suspension issues, but similar electrical complexity)
- Cadillac Escalade (Different luxury feel, comparable cost of ownership)
NHTSA Recalls
No active NHTSA safety recalls on file for the 2018 Mercedes-Benz Gls. Always verify with your VIN atnhtsa.gov.
What breaks on the 2018 Mercedes-Benz Gls?
Full reliability breakdown — engine, transmission, rust, electrical. With repair costs and mileage danger zones.
Autojunket OSC · OSC Transfer
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Mercedes-Benz Gls by Year
Compare AutoScores across nearby years of the Mercedes-Benz Gls. Click any year for its full report.
If You're Considering This, Also Look At
Similar class, similar year range — ranked by AutoScore.
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Where the 2018 Mercedes-Benz Gls report beats Carfax + CR
Carfax tells you if it crashed. Consumer Reports rates the whole nameplate. Autojunket tells you what will actually break on this specific year — and how to negotiate it.
Year-specific reliability score
Common problems + repair costs
Mileage danger zone map
AI negotiation script + walk-away price
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Frequently Asked Questions
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Sell your 2018 Mercedes-Benz Gls for what it's actually worth.
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