What goes wrong, what it costs, and what to check before you buy a used Mercedes-Benz X Class.
The Mercedes-Benz X Class occupies a niche position on the UK market.
We track 5 known issues across the Mercedes-Benz X Class range, with 2 classified as significant. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.
Found a Mercedes-Benz X Class? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
W470 (2017–2021) — Engine options included the 2.3 dCi, 3.0 V6 dCi. We track 5 known issues on this generation, with 2 classified as significant. The most significant concern is Electronic parking brake failure (£400–£650 to address).
The X-Class uses an electronic parking brake system that can fail on one side, creating an uneven braking force that affects parking brake efficiency. MOT data shows this model fails parking brake tests at over 24 times the national average, with both inoperative single-side failures and insufficient overall efficiency. The system relies on electric actuators at each rear brake caliper that can seize or lose power, requiring replacement of the actuator unit.
A failed parking brake actuator creates uneven braking forces and can cause the vehicle to roll on slopes. The affected side may not engage properly, leading to MOT failure and potential safety risk when parking on inclines. Replacement typically requires both actuators to be changed as a pair.
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.
This typically indicates emissions system faults including EGR valve problems, DPF sensor failures, or NOx sensor malfunctions. The shared Nissan/Renault diesel technology has known issues with carbon build-up in the intake system and DPF regeneration problems in urban driving conditions.
Emissions system faults typically require diagnostic work to identify the specific failed component, which may include EGR valve replacement, DPF regeneration or replacement, or NOx sensor replacement. Costs vary significantly depending on the root cause, from £300 for sensor replacement to £2,500 for DPF replacement.
Check for any engine warning lights on the dashboard. Ask about the car's MOT emissions history — repeated failures suggest underlying issues. A pre-purchase diagnostic scan is especially worthwhile to check for stored emissions fault codes.
3L diesel variants. This is likely related to the vehicle's pickup truck architecture and higher unsprung weight compared to conventional passenger cars.
Worn suspension components affect handling and may cause uneven tyre wear. While not immediately dangerous, deteriorated bushes and worn joints will eventually cause MOT failure and should be addressed to maintain safe handling characteristics. Multiple components may need replacement simultaneously.
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 X-Class shows higher than average brake disc wear rates, failing MOT tests for significantly worn brake discs at 2.9 times the fleet average. This is likely related to the vehicle's higher kerb weight compared to conventional passenger cars and the demands placed on the braking system in commercial use. Both front and rear discs can be affected, with the 3.0L V6 variants showing higher failure rates, possibly due to increased vehicle weight.
Worn brake discs will eventually fail the MOT test and affect braking performance. While not immediately dangerous at the point of MOT advisory, discs that are significantly worn should be replaced promptly. Replacement often involves both discs and pads simultaneously.
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.
MOT data shows the X-Class experiences fluid leaks at 4.3 times the national average, primarily affecting the 2.3L diesel variants between 40,000-60,000 miles. These leaks are significant enough to be considered environmentally hazardous or safety risks by MOT testers. Common sources include engine oil seals, gearbox seals, or differential oil leaks, with the shared Nissan Navara platform having known issues with timing cover oil seeps and rear axle seal failures.
Excessive fluid leaks will cause MOT failure and environmental concerns. While minor seepage may be manageable in the short term, significant leaks indicate seal failures that require attention. Oil loss can lead to engine damage if levels drop too low, and leaking fluids create safety hazards for other road users.
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 X Class common problems page.
Routine servicing (oil and filter change every 16k miles) typically costs £120–£180 at an independent garage.
See the full Mercedes-Benz X Class service schedule for every interval and cost breakdown.
The Mercedes-Benz X Class is a reasonable used buy provided you check for the issues outlined above. None of the problems we track are insurmountable, but they do reward buyers who inspect thoroughly and verify the service history before committing.
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 X Class, 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 X Class issues. We are not affiliated with any source listed.