What goes wrong, what it costs, and what to check before you buy a used Mercedes-Benz S Class.
The Mercedes-Benz S Class occupies a niche position on the UK market.
We track 5 known issues across the Mercedes-Benz S Class range, including 1 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 S Class? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
W220 (1998–2005) — Petrol options included the S280, S320, S430, S500, with S320 CDI on the diesel side. Our database flags 5 known issues on this generation, 1 of which are rated as safety-critical. The most significant concern is Structural weakness near suspension mounting points (£2,000–£5,000 to address).
W221 (2005–2013) — Petrol options included the S300, S350, S450/S500, with S320 CDI, S420 CDI on the diesel side. We track 4 known issues on this generation, with 3 classified as significant. The most significant concern is Steering box oil leaks (£800–£1,200 to address).
W222 (2013–2020) — Petrol options included the S400, S500, with S350d on the diesel side. 1 known issues affect this generation, none rated as critical. The most significant concern is Suspension component wear and deterioration (£400–£800 to address).
The W220 generation suffers from documented structural corrosion within 30cm of suspension component mounting points, particularly affecting the rear subframe area. This is a catastrophic safety defect where the load-bearing structure becomes so weakened that suspension components can detach from the vehicle. MOT data shows this affects 2.3L diesel variants most severely, with failure rates 40.9 times the national average at high mileage.
Complete structural failure can cause suspension components to separate from the vehicle while driving, resulting in total loss of control and potentially fatal accidents. Repair requires extensive structural welding and may not be economically viable on high-mileage examples. The vehicle is dangerous to drive if this defect is present.
Inspect the wheel arches, sills, jacking points and door bottoms carefully. Press gently on sills to check for soft spots. Look underneath for corrosion on structural components. Check the MOT history for corrosion-related advisories or failures.
Mercedes S-Class models from W220 and early W221 generations suffer from steering box oil leaks at dramatically higher rates than other vehicles. MOT data shows failure rates up to 123.1 times the national average, particularly on 5.0L petrol variants. The steering box develops leaks from internal seals, leading to power steering fluid loss and potential steering failure.
Progressive loss of power steering assistance makes the car increasingly difficult to steer, particularly at low speeds. Complete failure can result in very heavy steering that may be dangerous in emergency manoeuvring situations. Steering box replacement is expensive and labour-intensive on these models.
During the test drive, check the steering for excessive play, vibration or pulling to one side. Listen for groaning or whining when turning the wheel at low speed. Power steering fluid level and condition should be checked on hydraulic systems.
S-Class models develop excessive free play in the steering system at rates up to 63.6 times the national average. This affects steering precision and can indicate worn steering linkages, track rod ends, or steering box internal wear. The problem is particularly prevalent on 3.0L petrol variants and becomes progressively worse with age and mileage.
Excessive steering play reduces driving precision and increases stopping distances due to delayed steering response. In emergency situations, the driver may overcompensate for the delayed response, potentially causing loss of control. The car will fail its MOT test if free play exceeds legal limits.
During the test drive, check the steering for excessive play, vibration or pulling to one side. Listen for groaning or whining when turning the wheel at low speed. Power steering fluid level and condition should be checked on hydraulic systems.
The flexible coupling (flex disc) in the driveline deteriorates at rates up to 49.5 times the national average on S-Class models. This rubber and metal component connects the transmission output to the driveshaft and absorbs vibrations. When it fails, it can cause severe vibration, noise, and potentially dangerous driveline separation. The problem is most documented on 3.2L diesel variants.
A failing flex disc causes progressive driveline vibration and noise. Complete failure can result in driveshaft separation, causing total loss of drive and potential damage to the underbody. In extreme cases, a separated driveshaft can lock the rear wheels or cause the car to become uncontrollable.
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.
S-Class models experience suspension component wear at rates up to 32.4 times the national average, with over 13,000 MOT failures recorded across all variants. The complex multi-link suspension system uses numerous rubber bushes, ball joints, and linkages that deteriorate with age and mileage. This particularly affects ride quality and handling precision that these luxury vehicles are known for.
Worn suspension components progressively degrade ride quality, handling precision, and tyre wear patterns. While not immediately dangerous, continued deterioration can affect vehicle stability and braking performance. Multiple worn components typically need replacement simultaneously, making repairs expensive.
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 S Class common problems page.
Routine servicing (oil and filter change every 16k miles) typically costs £120–£180 at an independent garage.
The bigger-ticket items to budget for include automatic transmission fluid (£300–£450), spark plugs (£150–£300).
See the full Mercedes-Benz S Class service schedule for every interval and cost breakdown.
The Mercedes-Benz S Class has some well-documented weak points, including 1 safety-critical issue 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 S 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 S Class issues. We are not affiliated with any source listed.