Mercedes-Benz S-Class: common faults & what to check

Which Mercedes-Benz S-Class are you looking at?

4 generation variants documented. Pick the shape you recognise: the faults, the servicing and the timeline below all narrow to it. Free, no account needed.

Petrol

2 variants documented

2000–nowW2202000–nowW2203.5 V6 petrolPetrolDocumented issues4 knownSee faults & what to checkPhoto: Dinkun Chen via Wikimedia Commons, CC BY-SA 4.0.

2000–nowW2202000–nowW2204.7 V8 petrolPetrolDocumented issues4 knownSee faults & what to checkPhoto: Dinkun Chen via Wikimedia Commons, CC BY-SA 4.0.

Diesel

1 variant documented

2000–nowW2202000–nowW2203.0 dieselDieselDocumented issues4 knownSee faults & what to checkPhoto: Dinkun Chen via Wikimedia Commons, CC BY-SA 4.0.

Hybrid

1 variant documented

2000–nowW2202000–nowW2203.0 mild-hybridHybridDocumented issues4 knownSee faults & what to checkPhoto: Dinkun Chen via Wikimedia Commons, CC BY-SA 4.0.

Now narrow it to the engine

A 1.8 and a 2.4 of the same car do not fail the same way, so the faults below narrow to the engine as well as the year. Free, no account needed.

Start your free check on this Mercedes-Benz S-Class

No plate needed. You get the risk score, the buyer's checklist and the guided inspection for the exact car you picked above — not the whole nameplate.

The checks worth doing on a Mercedes-Benz S-Class before you hand over any money. Every documented fault is listed below, each with its own page.

• Serious issue

  Ask directly whether the balance shaft and idler gear have been replaced with the revised steel-tooth components and request documentation.

  See why

  M272 / M273 Balance Shaft and Idler Gear Plastic Tooth Failure

  The M272 3.5 V6 and M273 5.5 V8 petrol engines in the W221 S-Class suffer from a well-documented and catastrophic failure of the balance shaft and idler gear assembly. The gears use a plastic composite tooth profile that degrades, strips, or cracks typically between 80,000 and 130,000 km. When the balance shaft gear fails the debris can cause sudden oil pump drive failure or engine seizure. Mercedes formally acknowledged the fault, extended the warranty period on affected vehicles, and produced a revised steel-tooth replacement gear. Any W221 with unconfirmed original gears above 80,000 km must be treated as high risk.

  What you would notice

  • Sudden increase in engine vibration or rough running
  • Knocking or rattling from lower engine block
  • Oil pressure warning light if oil pump drive is affected
  • Engine failure or seizure in advanced cases

  Typically $3,500–$9,000 to put right.

• Serious issue

  Confirm whether the vehicle has standard AIRMATIC or the higher-specification Magic Body Control (the window sticker or options list will confirm).

  See why

  Magic Body Control (ABC) Active Hydraulic Suspension Failure

  W222 S-Class models with the optional Magic Body Control active body control hydraulic suspension suffer from expensive hydraulic component failures. The ABC pump, accumulator, and hydraulic cylinders at each corner are all documented failure points. Any leak in the high-pressure hydraulic circuit triggers a suspension fault and causes immediate ride height drop or loss of active body control. The system uses proprietary hydraulic fluid and requires specialist tooling. Hydraulic pump replacement alone costs $5,000 to $9,000 NZD at a Mercedes dealer. Independent specialists with appropriate equipment can reduce costs. Buyers must treat any W222 with Magic Body Control as carrying a significant potential liability.

  What you would notice

  • Active Body Control or suspension fault warning on dashboard
  • Car sitting unevenly or very low on one or more corners
  • Hydraulic fluid leak visible under front subframe or engine bay
  • Harsh uncontrolled ride when system loses hydraulic pressure

  Typically $3,500–$18,000 to put right.

• Serious issue

  Have the engine scanned before purchase - cam timing correlation codes on an M272 are a walk-away or heavy-renegotiation finding.

  See why

  Balance-shaft gear wear causing timing faults (3.5 M272 V6, S350 W221)

  Pre-facelift W221 S350s use the M272 V6, and engines built up to around 2008 can have a balance-shaft sprocket with inadequate surface hardening. The teeth wear, the timing chain loses tension on one bank, and the engine throws cam-timing codes (P0016 and related), runs rough and rattles - fixing it properly means engine removal to replace the balance shaft, a five-figure job done at a dealer and still a big bill at an independent. Mercedes faced a US class action over the issue and any goodwill programs are long expired, so on an affected car the cost is entirely the buyer's. A VIN/engine-number check can establish whether a particular engine falls in the at-risk build range.

  What you would notice

  • Check engine light with camshaft/crank correlation codes (e.g. P0016)
  • Rattle from the front of the engine, worst at cold start
  • Rough running or reduced power

  Typically $6,500–$13,000 to put right.

• Serious issue

  Ask for proof the front brake hose recall has been completed (dealer VIN check).

  See why

  Front brake hose deterioration causing fluid leak (W223, recall)

  Mercedes-Benz Australia recalled 423 W223 S-Classes built between 2020 and 2023 because the front axle brake hoses can deteriorate over time under high temperature and moisture, potentially leaking brake fluid and reducing braking performance. The fix is free replacement of the front brake hoses at a dealer. On any 2021-2023 car, confirm this recall work is done and check the brake fluid level and hose condition - a soft pedal or fluid loss on a car this heavy is an immediate safety issue.

  What you would notice

  • Brake fluid level warning
  • Soft or long brake pedal
  • Fluid weeping at the front brake hoses

  Typically $0–$800 to put right.

• Costly issue

  View the car cold, before the seller starts it: a W220 that has sat overnight should be sitting level.

  See why

  Airmatic air suspension failures - compressor, strut leaks and relay (W220)

  The W220's Airmatic system is its best-known money pit at this age: air leaks develop at the strut tops and pump pipework, compressors wear out (often killed by a stuck relay running them continuously), and level sensors fail. A failed side sags overnight or the car sits on its bump stops with an 'AIRMATIC - visit workshop' warning. Facelift cars got a more robust system but every W220 is now 20+ years old, so assume struts and compressor are consumables. Quality aftermarket struts have made per-corner repair far cheaper than the old dealer pricing.

  What you would notice

  • Car sagging at one corner or overall overnight
  • Compressor running long or loudly after start-up
  • 'AIRMATIC visit workshop' message
  • Floaty or crashy ride

  Typically $900–$4,000 to put right.

• Costly issue

  Inspect all four corners for even ride height after an overnight park.

  See why

  AIRMATIC Air Suspension Strut Failure

  The AIRMATIC air suspension fitted to W221 (2005 to 2013) and W222 (2013 to 2020) S-Class, and to W212 E-Class AIRMATIC variants, is prone to front air strut failure. The rubber air bag inside each strut perishes and develops slow air leaks, causing ride height drop typically overnight. Front struts fail most often and are more expensive to replace than rears. The air compressor in the boot runs harder and longer to compensate, eventually failing itself if not addressed. Many owners opt for conversion to passive coilovers to avoid ongoing air system costs, though this significantly changes the car's ride character.

  What you would notice

  • Car sitting low on one or more corners after overnight parking
  • AIRMATIC or suspension fault warning on dashboard
  • Air compressor running continuously or audibly at every start-up
  • Uneven ride height visible from front or rear of vehicle

  Typically $900–$3,500 to put right.

What these repairs cost on other cars

Some of the Mercedes-Benz S-Class’s documented faults are repairs other models share. Each page lists the documented NZ cost for every model it affects.

• Hybrid Battery Replacement Cost
• Timing Chain Replacement Cost
• DPF Repair and Replacement Cost

Other Mercedes-Benz models