Commanding luxury SUV with three generations of evolution
The Mercedes-Benz ML (1998-2015, renamed GLE from 2015) established Mercedes in the UK luxury SUV market. The W163 (1998-2005), W164 (2006-2011) and W166 (2012-2015) generations are all available used. W164 ML350 examples average around £7,900. The ML competes with the BMW X5, Audi Q7 and Range Rover Sport. Early models suffered poor reliability but the W166 generation significantly improved. All generations are now affordable but maintenance costs remain Mercedes-level.
We track 5 known issues across the Mercedes-Benz ML 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 ML? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
W163 (1998–2005) — Petrol options included the 3.2 V6, 3.7 V6, 4.3 V8, 5.0 V8, 5.4 AMG, with 2.7 CDI, 3.2 CDI on the diesel side. Our database flags 2 known issues on this generation, 1 of which are rated as safety-critical. The most significant concern is Suspension component failure (£200–£800 to address).
W164 (2005–2011) — Petrol options included the 3.5 V6, 6.2 AMG, with 3.0 CDI, 3.5 CDI, 3.7 CDI, 4.0 CDI on the diesel side. Our database flags 5 known issues on this generation, 2 of which are rated as safety-critical. The most significant concern is Suspension component failure (£200–£800 to address).
W166 (2011–2019) — Petrol options included the 5.5 AMG, with 2.1 CDI, 3.0 CDI on the diesel side. Our database flags 3 known issues on this generation, 1 of which are rated as safety-critical. The most significant concern is Brake hose deterioration and failure (£150–£300 to address).
The ML suffers from premature suspension component failure, particularly control arm bushes, ball joints, and anti-roll bar links. MOT data shows this model fails suspension inspections at up to 107 times the national average rate, with 2.7 CDI variants worst affected. The combination of vehicle weight, suspension design, and UK road conditions causes accelerated wear. Later W166 generation addressed some of these issues with redesigned components.
Failed suspension components compromise vehicle stability and braking performance, creating a serious safety risk. Worn ball joints can separate completely, causing loss of steering control. Repair costs vary widely depending on which components have failed, but comprehensive suspension rebuilds can exceed £2,000-£3,000 due to the complexity of the ML's multi-link system.
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 ML suffers from premature brake hose deterioration, with MOT data showing brake hose failures at up to 17 times the national average on 3.0 CDI models. The flexible brake hoses, particularly those connecting to the front calipers, are prone to cracking and bulging due to the high brake pressures required by the vehicle's weight and the heat generated during braking. Age and exposure to road salt accelerate deterioration.
Brake hose failure creates an immediate and extreme safety risk through sudden loss of braking ability. A burst hose will result in complete brake failure on the affected circuit, relying on the remaining circuit and handbrake for stopping power. The vehicle should not be driven if brake hose deterioration is suspected. Replacement of all brake hoses is typically recommended once one fails.
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 ML experiences frequent handbrake cable failures and adjustment problems, with MOT data showing cable damage at up to 53 times the national average. The cables are prone to stretching, fraying, and seizing in their guides, particularly on 3.5 CDI and 3.0 CDI variants. The handbrake mechanism operates rear disc brakes through a cable and lever system that is vulnerable to corrosion and mechanical wear in UK conditions.
A failing handbrake creates a serious safety risk, particularly on slopes, and will result in an MOT failure. Cable failures can cause the handbrake to become completely inoperative or to drag continuously, leading to brake disc overheating and premature pad wear. Complete cable replacement typically costs £300-£600 depending on which cables have failed.
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.
CDI diesel ML models experience frequent emissions system failures, with MOT data showing smoke opacity failures at up to 38 times the national average rate. Common issues include EGR valve clogging, diesel particulate filter (DPF) blockage on later models, and turbocharger problems leading to excessive smoke production. The 2.7 CDI and 3.0 CDI engines are particularly affected due to their sensitivity to fuel quality and driving patterns.
Emissions system failures result in automatic MOT failure and increasingly expensive repair costs. DPF replacement can cost £2,000-£3,000, while EGR valve cleaning or replacement typically costs £400-£800. Driving with a blocked DPF risks engine damage from back-pressure, and continued use may lead to complete DPF destruction requiring 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.
ML models equipped with AIRMATIC air suspension experience frequent component failures, particularly air springs, compressor pumps, and height sensors. The system is complex and expensive to repair, with individual air spring failures often leading to complete system replacement. The compressor pump works excessively hard when air springs leak, leading to premature pump failure. UK road conditions and age cause rubber air springs to crack and leak.
Air suspension failures result in poor ride quality, potential damage to other suspension components, and expensive repair bills. Individual air springs cost £400-£800 each, while compressor replacement costs £800-£1,200. Many owners convert to conventional coil springs to avoid ongoing air suspension costs, though this affects ride quality and vehicle dynamics.
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.
For the full breakdown of all 5 tracked issues with repair costs, see the Mercedes-Benz ML common problems page.
Based on 206k real DVSA MOT tests, the Mercedes-Benz ML fails more often than average on several items. The biggest outlier is anti-roll bar links worn at 190x the fleet average, followed by stop lamp position or intensity not in accordan... (108x).
When viewing a specific car, check its MOT history for recurring advisories in these categories. See the full Mercedes-Benz ML MOT failure breakdown for data at every mileage point.
Routine servicing (oil and filter change every 12k miles) typically costs £120–£180 at an independent garage.
The bigger-ticket items to budget for include automatic transmission fluid (£250–£350).
See the full Mercedes-Benz ML service schedule for every interval and cost breakdown.
The Mercedes-Benz ML 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. 2012-2015 W166 generation ML350 BlueTEC is the best buy, offering dramatically improved reliability, modern safety equipment and refined driving dynamics. For budget buyers, 2009-2011 W164 ML350 CDI models are generally sound if serviced by specialists. Avoid 2006-2008 W164s due to balance shaft and differential problems. The 2005 and 2010 model years are singled out as particularly reliable. Always demand full Mercedes dealer or specialist service history.
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 ML, 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 ML issues. We are not affiliated with any source listed.