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Mercedes-Benz S-Class S 450 d 4MATIC common faults.

2020–2026, saloon, diesel, 367 HP.

The fault list covers: OM656EVO, OM656M engine, MB7250 transmission.

What you save stays on this device only. My saves

2 fault write-ups. Both are important. 6 recalls.

If you know the year, pick it. Faults for other years drop out of the list.

Before you buy

Known faults

2 important faults

critical1

OM654 / OM656: vacuum controlled coolant pump leak, fire risk

critical

On the OM654 and OM656 diesels the maker started a recall over the vacuum controlled coolant pump (maker action code: 2090008). The fault: a leak can develop between the coolant and the vacuum circuit; if coolant reaches the electric switching valves, an electrochemical reaction can raise the temperature of the part, and a fire risk cannot be ruled out.

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The fix: replacing the electric switching valve and a software update. The campaign started at the end of 2021; the affected group is the C-Class, E-Class and other OM654/OM656 models.

A recall on the model does not mean it was carried out on this car. Only the franchised dealer can tell you, by VIN.

What to check

  • Ask the franchised dealer by VIN: is action 2090008 OPEN or CLOSED
  • Check the coolant level and look around the vacuum system for leaks
  • Ask for the service sheet: a switching valve replacement plus a software update is part of the campaign
1 more steps in the write-up

expensive1

OM654 / OM656 diesel: roller finger follower wear and DPF driven oil dilution

expensive

The modern OM654 four cylinder diesel (and the modular OM656 six cylinder) carries two weaknesses on the used market that reinforce each other.

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1) Roller finger followers (Rollenschlepphebel). According to the German technical press, on some cars the followers wear early at around 100,000 to 120,000 km. On 10 July 2018 the maker introduced a strengthened follower from engine number 80278367 (new part number A6540505701 in place of the old A6540501100). On early built cars the risk is higher. A faulty follower develops so much heat that the removed metal shows blue discolouration (Anlaufspur).

2) Oil dilution. The post injection needed to regenerate the particulate filter puts diesel fuel into the engine oil. With short urban use the engine does not get warm enough, the fuel does not evaporate, the oil thins out, and the follower and valvetrain are exactly what suffers most from poor lubrication.

The timing chain sits on the gearbox side: if it stretches, the replacement is labour intensive. There are few complaints of a broken chain, but on the early series about 5,000 cars were recalled for a weak chain, and the Tritan 15 coating was changed to Tritan 18.

between 80,000 and 160,000 km

What to check

  • Listen to the engine on a cold start: metallic ticking or rattling from the follower or the chain is suspect
  • Ask for the engine number: cars below 80278367 (before July 2018) are the old follower group
  • Check the service book: how often and with what oil (MB 229.52 is recommended) it was changed. Long intervals plus urban use is the worst pairing
2 more steps in the write-up

Checklist

Mercedes-Benz S-Class S 450 d 4MATIC

First what you would check on any car. Then the faults of this model.

Before you buy

Checklist

The printed sheet starts with what you would check on any car. What you tick stays on this device only.

On every car

Ask the owner

Faults of this model

vinkodex.com · Before you buy it, see what can go wrong.

Official recall6 recallsShow

The manufacturer fixes these for free at a franchised dealer. Ask with the VIN whether it was done.

Most recent: 18 March 2023

A12/00856/23Safety recallInjuries18 March 2023 · EU Safety Gate

The instrument panel may detach, thereby affecting the deployment performance of the passenger airbag in the event of an accident, increasing the risk of injury. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: 18/03/2023

The authority's notice

A12/00485/24Safety recallInjuriesno date · EU Safety Gate

The catch fixing the wheel hubcaps may not withstand the pressures encountered during driving. In such cases, the hubcaps could detach from the vehicle, increasing the risk of accident and injury to other road users. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/00610/22Safety recallInjuriesno date · EU Safety Gate

Improper welding on the rear axle can cause the thrust rod to come loose from the rear axle bracket. This may cause the vehicle to swerve in response to the road surface or the vehicle may skid sideways during emergency braking. This leads to loss of control over the vehicle, increasing the risk of an accident. The product does not comply with the Regulation on the approval and market surveillance of Motor Vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/02133/23Safety recallFire, Injuriesno date · EU Safety Gate

The fuse box of the engine compartment may be defective. High electrical currents could increase the temperature, creating a risk of fire. This is turn can lead to an electricity interruption and the vehicle may lose propulsion power, increasing the risk of an accident. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/02416/23Safety recallFire, Injuriesno date · EU Safety Gate

The 12 volt ground wire screw in the trunk may be defective, which can lead to that certain electronic stability program (ESP) functions can be disabled or strong electrical currents may lead to a local increase in temperature, increasing the risk of an accident or fire. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/03598/24Safety recallEnvironment, Fire, Injuriesno date · EU Safety Gate

In the event of an independent hardware failure, the lambda control in the Engine Control Unit (ECU) software can erroneously increase the amount of injected fuel during cylinder deactivation. As a result, exhaust temperatures can increase and this can damage surrounding components (e.g. engine wiring harness, catalytic converter). This can create an unexpected loss of propulsion, increasing the risk of accidents and injuries. Moreover, this can increase the risk of fire. In addition, local statutory exhaust emission limits could be exceeded. The product does not comply with the Regulation on the approval and market surveillance of motor vehicles and their trailers, and of systems, components and separate technical units intended for such vehicles.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

Engine and transmission

2 engines · 1 transmissions

OM656EVO

17–270 kW (23–367 HP) · diesel

MB7250 · 9G-Tronic, longitudinal (Mercedes 725.0 / NAG3)

automatic · 9 speed

Torque limit700 Nm
MakerMercedes-Benz

We built the code from the model and the gear count. The factory sheet does not state it. More than one engine code is possible. The fault list shows the faults of each.

Variant data

What is in this version

Factory data

Trim
S 450 d 4MATIC
Body
saloon
Fuel
diesel
Transmission
automatic
Engine size
2989 cc
Power
270 kW (367 HP)
Drive
AWD
Production
2020–2026

Factory service interval

The manufacturer specifies this for this version. Of the mileage and the time, the one that comes first is the one that counts.

  • Air filter

    • 60,000 km or 4 years

  • Cabin (pollen) filter

    • 30,000 km or 2 years

  • Brake fluid change

    • first: 3 years, then 2 years(first change at 3 years, then every two years)

  • Fuel filter, diesel

    • 60,000 km or 2 years
All W223 versions

Information, not an expert opinion

We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.

  • A fault on the list does not mean the car you are looking at has it.
  • A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
  • You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.
Details in the terms