MERCEDES GLS (2017)
Running costs, reliability data, and common problems from 1,425 real MOT tests.
Annual Cost
£1,695
£141/month
MOT Pass Rate
92%
Excellent
Road Tax
£195
Flat rate/year
Insurance
Grp 30-42
2987cc Diesel
Great Choice
92% pass rate, £1695/year to run. 10 points above average.
Check a specific MERCEDES GLS
Enter a reg plate for full MOT history, mileage check, health score, running costs, and reliability data. Free, instant, no signup.
Annual Running Costs
~40 mpg
Flat rate (post-2017)
Low estimate due to excellent reliability
Based on 7,400 miles/year (UK average), current fuel prices, and repair likelihood from MOT data. Insurance not included.
Get an insurance quote for this MERCEDES GLS
Compare quotes and find the best deal
Reliability Verdict
Excellent reliability. Very few MOT failures. That's 10 points above the national average of 82%. It also outperforms the MERCEDES brand average of 87%.
At 9 years old, 92% of MERCEDES GLSs from 2017 passed their MOT first time in 2026. That's based on 1,425 tests across the UK. The average mileage at this age is 62,721 miles.
Got a MERCEDES GLS you're looking at?
Enter the reg plate to check its specific MOT history, mileage, and health score.
How Does It Compare?
Mileage Analysis
62,721
Average miles
66,600
Expected for age
The average 2017 MERCEDES GLS has 62,721 miles on the clock, which is in line with the expected 66,600 miles for a 9-year-old car, suggesting normal everyday use.
Looking at a specific MERCEDES GLS?
Enter its reg plate for a free check with full MOT history, mileage verification, and predicted costs.
Best Year to Buy?
The most reliable year is the 2016 model with a 93% MOT pass rate, while the 2018 model has the lowest at 90%. The 2017 sits between the two at 92%.
MERCEDES GLS by Year
Similar Cars to Consider
Check a Specific Mercedes Gls
Enter a reg plate to get the full MOT history, health score, and mileage verification.
Upgrade to Premium (£4.99) for stolen, finance, and write-off checks.
About the 2017 MERCEDES GLS
The 2017 MERCEDES GLS is a large car with a 2987cc diesel engine. 1,425 of these vehicles were MOT tested in 2026, making it a reasonably common sight on UK roads. It ranks in the top 25% of all 2017 cars for reliability.
With an average of 62,721 miles at 9 years old, MERCEDES GLS owners drive about as much as the UK average.
2017 MERCEDES GLS Fuel Costs
The 2987cc diesel engine is on the larger side, so fuel won't be this car's strong point. Expect around 40 mpg in mixed driving, which works out to roughly £1,245 per year at current diesel prices of 148p per litre (based on 7,400 miles per year). Diesel cars of this age should have their DPF (diesel particulate filter) checked, as replacements can be costly.
What does it cost to own a 2017 MERCEDES GLS?
Total estimated annual running cost is £1,695 (£141/month), broken down as £1245 fuel, £195 road tax, £55 MOT, and £200 predicted repairs. The low repair estimate reflects the excellent 92% pass rate. These cars rarely fail their MOT, so unexpected bills are less likely.
MERCEDES GLS Reliability Trend
The MERCEDES GLS has maintained consistent MOT pass rates across model years, varying by only 2 percentage points.
Buying a Used 2017 MERCEDES GLS
At 9 years old, this is a solid used buy if you find one with good service history. Depreciation has levelled off, so you won't lose much more value. Focus on condition over mileage. If you're flexible on year, the 2016 model has the highest pass rate at 93%.
Common Issues to Watch For
Based on the 2017 MERCEDES GLS's fuel type, age, and engine size, these are the most likely problem areas to check.
DPF (Diesel Particulate Filter)
Watch outShort journeys clog the DPF. Replacement costs £1,000-£2,500. Check the DPF warning light and ask about driving patterns.
Turbo Wear
Watch outDiesel turbos work harder and wear faster. Listen for whining noises and check for oil leaks around the turbo housing.
AdBlue System
Medium riskPost-2015 diesels use AdBlue for emissions. Sensor failures and tank heater issues are common. Budget £200-£500 for repairs.
EGR Valve
Watch outExhaust Gas Recirculation valves clog with carbon deposits, causing rough running and poor economy. Cleaning costs £150-£300, replacement £300-£600.
Dual Mass Flywheel
Watch outLarger diesel engines put extra strain on the dual mass flywheel. Listen for rattling at idle. Replacement with clutch is £800-£1,500.
Suspension Wear
Medium riskShock absorbers, springs, and anti-roll bar links typically need attention around this age. Listen for clunks over bumps and check for uneven tyre wear.
Service History
Low riskAlways request a full service history. Regular servicing is the single best indicator of how well a car has been maintained, regardless of mileage.
Running Costs Compared
How the 2017 MERCEDES GLS stacks up against similar cars for annual running costs, insurance, and tax.
| Car | Pass Rate | Fuel/yr | Tax/yr | Insurance | Total/yr |
|---|---|---|---|---|---|
| MERCEDES GLS(2017) | 92% | £1245 | £195 | Grp 30-42 | £1695 |
| MERCEDES E(2019) | 90% | £1245 | £190 | Grp 30-42 | £1690-£5 |
| MERCEDES GLC(2018) | 91% | £1245 | £190 | Grp 30-42 | £1690-£5 |
| AUDI A5(2017) | 89% | £1245 | £190 | Grp 30-42 | £1840+£145 |
| FORD RANGER(2019) | 87% | £1245 | £190 | Grp 35-50 | £1840+£145 |
Estimates based on 7,400 miles/year, current fuel prices, and MOT data. Insurance groups are indicative. Actual costs vary by driver, location, and usage.
Related Mercedes Models
Explore other Mercedes cars or similar models in the same category.
MERCEDES A
2019 · 1461cc Diesel
MERCEDES C
2017 · 1991cc Hybrid
MERCEDES A-CLASS
2017 · 1461cc Diesel
MERCEDES E
2019 · 2925cc Diesel
MERCEDES GLC
2018 · 2987cc Diesel
AUDI A5
2017 · 2967cc Diesel
Related Guides
In-depth articles relevant to the Mercedes Gls.
Petrol vs Diesel in 2026: Which Actually Costs Less to Own?
8 min read
Buying GuideCars That Lose Value Fastest: Models to Avoid for Depreciation
8 min read
Running CostsCheapest Cars to Run in 2026: Real Data from 19.8 Million MOT Tests
9 min read
Buying GuideFord Fiesta Common Problems (2026): What to Check Before Buying
13 min read
ReliabilityFord Puma Problems: 7 Issues Owners Report (2026)
13 min read
Check a specific MERCEDES GLS
Enter the reg to see its MOT history, mileage check, and predicted costs.
Premium History Check
Buying a MERCEDES GLS? Our premium check covers:
- Stolen check (PNC)
- Outstanding finance
- Write-off history (Cat A/B/N/S)
- Previous owners count
Competitors charge £10-£20 for the same data