CarValidator
BG·EN

ML280/320/350 CDI 3.0 V6 (OM642)

2005–2011 · diesel · 2987cc · 224hp

Engine codes: OM642

Maint. Sensitive

Reliability, common problems and owner reviews for the Mercedes Benz M-Class (ML) ML280/320/350 CDI 3.0 V6 (OM642). Check this before you buy used.

The 3.0 V6 CDI (OM642) is the volume ML engine and the one to buy — torquey, refined and well-matched to the big SUV, the same robust six used across C/E-Class, S-Class and the Jeep Grand Cherokee. Two signature niggles to budget for: the oil-cooler seals between the V harden and leak oil (common, labour-involved), and the intake swirl-flap/manifold assembly (the 'Drallklappen' actuator) fails. Plus EGR/DPF and high-mileage injection. With those addressed and good history it's a dependable long-hauler.

Same engine, other cars

This is the same physical engine (OM642) sold under different names across brands. Reliability is broadly shared — cross-check these:

Known Issues

Oil-cooler seal leakrecurring

Oil-cooler seals (in the V, under the intake) harden and leak oil — common OM642 job, labour-heavy.

Fix / Workaround: Replace oil-cooler seals (intake off).

Repair cost: €400–€1100

Typically appears after: 130,000 km

Intake swirl-flap / manifoldrecurring

Swirl-flap actuator/manifold ('Drallklappen') fails → limp/fault; can shed parts.

Fix / Workaround: Replace/repair intake manifold + actuator.

Repair cost: €300–€1000

Typically appears after: 140,000 km

EGR / DPF / injectorsrecurring

EGR, DPF and injectors at higher mileage.

Fix / Workaround: Service EGR; motorway regens; injector test.

Repair cost: €250–€1400

Mileage Thresholds

After 200,000 km: Oil-cooler + swirl-flap territory.

Pre-Purchase Checklist

  • ☐Oil-cooler seal leak history
  • ☐Swirl-flap/intake manifold history
  • ☐The engine to buy — shared robust V6

Frequently asked questions

Is the Mercedes Benz M-Class (ML) ML280/320/350 CDI 3.0 V6 (OM642) reliable?

Maint. Sensitive — The 3.0 V6 CDI (OM642) is the volume ML engine and the one to buy — torquey, refined and well-matched to the big SUV, the same robust six used across C/E-Class, S-Class and the Jeep Grand Cherokee. Two signature niggles to budget for: the oil-cooler seals between the V harden and leak oil (common, labour-involved), and the intake swirl-flap/manifold assembly (the 'Drallklappen' actuator) fails. Plus EGR/DPF and high-mileage injection. With those addressed and good history it's a dependable long-hauler.

What are the common problems and reviews for the Mercedes Benz M-Class (ML) ML280/320/350 CDI 3.0 V6 (OM642)?

The most commonly reported problems: Oil-cooler seal leak, Intake swirl-flap / manifold, EGR / DPF / injectors.

Is a used Mercedes Benz M-Class (ML) ML280/320/350 CDI 3.0 V6 (OM642) worth buying?

Fine if serviced correctly — but it punishes neglect hard. History and the right consumables matter.