What goes wrong, what it costs, and what to check before you buy a used Mercedes-Benz GL 320.
The Mercedes-Benz GL 320 occupies a niche position on the UK market.
We track 5 known issues across the Mercedes-Benz GL 320 range, including 2 rated as safety-critical. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.
Found a Mercedes-Benz GL 320? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
X164 (2006–2012) — Engine options included the 3.0L V6 CDI. Our database flags 5 known issues on this generation, 2 of which are rated as safety-critical. The most significant concern is Brake pipe corrosion (£400–£800 to address).
The GL 320 uses steel brake pipes that are vulnerable to corrosion from road salt and moisture. The pipes run along the underside of the vehicle where they are exposed to road spray and debris. MOT data shows this model fails brake pipe corrosion checks at 3.5x the national fleet average, with failures occurring from 80,000 miles onwards. The large, heavy SUV body places high demands on the brake system, making any reduction in hydraulic pressure from corroded lines a significant safety concern.
Corroded brake pipes can fail completely under braking pressure, leading to total brake failure and potential serious accident. Even partial corrosion reduces braking efficiency and increases stopping distances. Brake pipe replacement typically requires removal of body panels and may involve welding new mounting points.
Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.
The flexible brake hoses on the GL 320 connect the rigid brake pipes to the brake calipers at each wheel. These rubber hoses are subject to constant flexing as the suspension moves and exposure to heat from the brake discs. MOT data shows this model fails flexible brake hose checks at 6.8x the national fleet average, typically from 100,000 miles. The failure pattern is worsening, suggesting age-related deterioration as the fleet ages.
Severely deteriorated brake hoses can burst under pressure, causing immediate brake failure and potential serious accident. Even minor deterioration reduces braking effectiveness and can cause the brake pedal to feel spongy or require pumping. Replacement requires brake system bleeding.
Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.
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. The GL 320's high ground clearance and off-road capability expose these boots to damage from stones and debris. MOT data shows this model fails CV joint boot checks at 3.7x the fleet average, typically from 100,000 miles. Once the boot fails, contamination destroys the CV joint rapidly.
Once a CV joint boot fails, dirt and water contaminate the joint and wash out the protective grease. The joint will fail within a few thousand miles, causing complete loss of drive to that wheel and potential damage to the differential. Early boot replacement is much cheaper than joint replacement.
Listen for clunking or vibration from underneath when pulling away or changing direction. Check for play in the driveshafts by rocking the car in gear with the handbrake on. Worn CV boots are a telltale sign — look for grease splatter around the inner wheel arch.
The GL 320's shock absorbers must cope with the weight of a large SUV and varying load conditions from towing or cargo. The combination of weight and the vehicle's off-road capability places high demands on the dampers. MOT data shows this model fails shock absorber checks at 2.0x the fleet average, typically around 100,000 miles. Failed dampers compromise both handling and braking performance on this heavy vehicle.
Failed shock absorbers severely compromise the vehicle's handling, braking performance, and ride quality. On a heavy SUV like the GL 320, worn dampers increase stopping distances and can cause dangerous instability during emergency maneuvers. Tyres wear unevenly and suspension components experience accelerated wear.
Listen for knocking, clunking or rattling over bumps during the test drive. Inspect the underside for corroded or cracked suspension components. Check the MOT history for suspension-related advisories, which often predict future failures.
The GL 320 develops oil and fluid leaks from various engine and transmission seals as it ages. Common leak points include the engine oil sump gasket, transmission oil cooler lines, and power steering system. MOT data shows this model fails environmental fluid leak checks at 3.8x the fleet average, with the issue worsening as the fleet ages. While not immediately dangerous, significant leaks can harm the environment and indicate deteriorating seals.
Significant fluid leaks can lead to component damage if levels drop too low. Engine oil leaks onto hot exhaust components create fire risk and unpleasant smell. Environmental agencies can impose penalties for vehicles that leak excessively. Regular monitoring and timely seal replacement prevent more expensive component failure.
Check the oil level before the engine is started. Ask the seller how often they top up the oil between services. After a test drive, check the level again and look behind the car for blue or grey exhaust smoke under acceleration.
For the full breakdown of all 5 tracked issues with repair costs, see the Mercedes-Benz GL 320 common problems page.
Based on 2k real DVSA MOT tests, the Mercedes-Benz GL 320 fails more often than average on several items. The biggest outlier is reflector defective or damaged by up to 50% of ... at 13x the fleet average, followed by cable damaged or knotted (12x).
When viewing a specific car, check its MOT history for recurring advisories in these categories. See the full Mercedes-Benz GL 320 MOT failure breakdown for data at every mileage point.
Routine servicing (oil and filter change every 15k miles) typically costs £180–£250 at an independent garage.
The bigger-ticket items to budget for include automatic transmission fluid (£300–£400).
See the full Mercedes-Benz GL 320 service schedule for every interval and cost breakdown.
The Mercedes-Benz GL 320 has some well-documented weak points, including 2 safety-critical issues that demand careful checking. The right example, properly maintained, can still be a sound purchase — but cutting corners on the pre-purchase inspection is not advisable.
Before committing, check the car's full MOT history, verify the service record is complete, and if possible arrange a specialist inspection. Enter any registration into our free report to see the complete picture.
Get Car Wise maintains a database of known mechanical issues for every popular car on UK roads, tracking the faults that owners, specialists and DVSA data reveal.
When you run a report on a specific Mercedes-Benz GL 320, we cross-reference the exact variant, engine and age against our database of 5 known issues. Combined with full MOT history analysis, mileage verification and DVLA data, you get a complete picture before viewing.
Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Get Car Wise Score.
This guide was compiled from independent expert reviews, DVSA MOT data, specialist workshops and our own database of 5 known Mercedes-Benz GL 320 issues. We are not affiliated with any source listed.