Mercedes Benz Gl 320 MOT Failures
An analysis of 3,440 real DVSA MOT tests on the Mercedes Benz Gl 320 — what fails, how often, and how that compares to every other car on UK roads. Generations covered: X164 (2006–2012).
Where the Mercedes Benz Gl 320 fails its MOT
The single biggest MOT failure point on the Mercedes Benz Gl 320 is brake pedal anti-slip provision missing, loose ... — this model is 8.7 times more likely to fail on this item than the average car on UK roads. That makes it worth watching for anyone buying or owning this model. Across 3,440 MOT tests, 4.33% of all Mercedes Benz Gl 320 tests recorded this as a failure.
Brake failures on the MOT range from worn pads and discs (routine maintenance) to corroded brake lines and seized calipers (more serious). Check for any pulling under braking and listen for grinding.
Other notable weak points include reflector defective or damaged by up to 50% of ... (13x the fleet average), cable damaged or knotted (12x the fleet average), seat mounting fault (11x the fleet average), and power steering fault (7.0x the fleet average). These ratios compare the Mercedes Benz Gl 320's failure rate on each item against the national average for all cars tested — a ratio of 10x means this model fails ten times more often than a typical car.
The failures span 5 categories: Brakes, Lights & Electrics, Seatbelts & Airbags, Steering, Suspension. If you're inspecting a Mercedes Benz Gl 320 before purchase, these are the areas to focus on — and if any have been flagged as advisories on a previous MOT, they're likely to become failures in the near future.
Known issues beyond the MOT
An MOT only tests roadworthiness at a single point in time — it won't catch developing faults, intermittent problems, or issues that haven't yet reached the failure threshold. These are the issues that Mercedes Benz Gl 320 specialists and owners flag most frequently, drawn from manufacturer technical bulletins, workshop data, and verified owner reports.
Brake pipe corrosion (X164) Dangerous
The GL 320 uses steel brake pipes that are vulnerable to corrosion from road salt and moisture. Affects X164; typical independent garage repair cost is £400–£800.
Brake hose deterioration (X164) Dangerous
The flexible brake hoses on the GL 320 connect the rigid brake pipes to the brake calipers at each wheel. Affects X164; typical independent garage repair cost is £200–£400.
CV joint boot deterioration (X164) Major
The constant velocity (CV) joints at each end of the driveshafts are protected by rubber boots that contain the grease and exclude dirt and water. Affects X164; typical independent garage repair cost is £150–£250.
Shock absorber deterioration (X164) Major
The GL 320's shock absorbers must cope with the weight of a large SUV and varying load conditions from towing or cargo. Affects X164; typical independent garage repair cost is £400–£600.
For the complete picture — including repair costs across independent, specialist, and dealer garages — see the full Mercedes Benz Gl 320 common problems breakdown.
What to check before buying a Mercedes Benz Gl 320
Based on the MOT failure data and known issues above, here's what to prioritise when inspecting a Mercedes Benz Gl 320:
Brakes — check for brake pedal anti-slip provision missing, loose ..., cable damaged or knotted, brake hoses perished or damaged. Lights & Electrics — check for reflector defective or damaged by up to 50% of ..., light unit fault. Seatbelts & Airbags — check for seat mounting fault.
Beyond the MOT items, ask specifically about brake pipe corrosion and brake hose deterioration. These won't show up on a standard MOT but can be expensive to fix — repairs start from £400. A specialist pre-purchase inspection is worth the investment on this model.
Always check the car's full MOT history for patterns — recurring advisories often become failures within 12 months. And verify the service history to confirm maintenance has been kept up to schedule. Enter any reg into our free car check to see the complete picture.
Looking at a specific Mercedes Benz Gl 320?
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Mercedes Benz Gl 320 MOT FAQs
What are the most common MOT failures on a Mercedes Benz Gl 320?
Based on 3,440 DVSA MOT tests, the most common failure is brake pedal anti-slip provision missing, loose ... — at 9x the national fleet average. Other frequent failures include reflector defective or damaged by up to 50% of ... and cable damaged or knotted.
Is the Mercedes Benz Gl 320 reliable based on MOT data?
The Mercedes Benz Gl 320 has 8 MOT failure categories above the fleet average. Specialists also flag brake pipe corrosion as a concern. A pre-purchase inspection and service history check are recommended.
What MOT failures should I expect at high mileage?
Above 100,000 miles, the Mercedes Benz Gl 320 most commonly fails on reflector defective or damaged by up to 50% of ... and cable damaged or knotted. Under 60,000 miles, the main issues are .
How do I check a Mercedes Benz Gl 320's MOT history?
Enter the registration number into our free car check above. You'll see every MOT test result, advisories and failures, mileage readings, write-off status, and finance checks.
MOT failure data sourced from DVSA bulk test records via data.gov.uk. Ratios compare this model's failure rate against the national fleet average. Known issues sourced from manufacturer bulletins, specialist workshops, and verified owner reports.