OM642 engine reliability: strengths, watch-outs, and known issues

OM642, OM642.820, OM642.826, OM642.832, OM642.835, OM642.838, OM642.852, OM642.854, OM642.858, OM642.861, OM642.910, OM642.920, OM642.930, OM642.940, OM642.961, OM642DE30LA, OM642LSDE30LA/642.826, OM642LSDE30LA/642.873 · 2005–2018 · 33 models
"Is the OM642 reliable, and what should you check?"

Strength: High service life with proper maintenance. Common watch-out: Intake swirl flaps jam. OEM life note: not limited; often cited in practice: 400,000 km. This family appears across roughly 33 fitment bands in 2005–2018; service history, oil/cooling records, and engine-code verification matter.

Family

OM642

Variants

OM642, OM642.820, OM642.826, OM642.832, OM642.835, OM642.838, OM642.852, OM642.854, OM642.858, OM642.861, OM642.910, OM642.920, OM642.930, OM642.940, OM642.961, OM642DE30LA, OM642LSDE30LA/642.826, OM642LSDE30LA/642.873

Fuel / induction

Verify on the car report

Production band

2005–2018

Known issues

Most frequent / serious themes first; amber labels mark year gates.

Oil cooler leaks

Heavier after 2010

The most known problem of this diesel is oil cooler gasket leaks. Since the cooler is located in the V of the engine, replacing the cheap gaskets is expensive. Around 2010 the design was revised and such leaks no longer occur.

Fuel system issues

Often reported

The engine uses a reliable Bosch Common Rail fuel system, but its piezo injectors are very sensitive to fuel quality and expensive. Also, regular failures of the fuel quantity control valve in the high-pressure pump are noted.

Swirl flap problems

Often reported

The intake manifold has steel swirl flaps, but they are actuated by a servo with plastic rods that often break. The problem is worsened by intake clogging due to a weak crankcase ventilation membrane.

Turbocharger issues

Often reported

The Garrett turbo itself is durable and easily lasts 300,000 km, but its variable geometry system often sticks due to heavy soiling. Most often the turbo is damaged by debris from cracked welds in the exhaust manifold.

Other problems

Often reported

This engine is known for frequent oil leaks and a not very durable oil pump. Since it is sensitive to oil pressure, spun bearings are not uncommon.

Service & life

Rated life (OEM)not limited
Life in practice400,000 km
Timing drivechain
Timing failure effectbends valves
Oil change intervalevery 10,000 km
Oil capacity (engine)8.8/ 10.8/ 12.8 L *
Oil capacity (change)8.0/ 10.0/ 12.0 L *
Oil specification5W-30, MB 228.51/229.51
Valve adjustmentnot required
Valve adjustment methodhydraulic lifters
Oil filter10,000 km
Air filter10,000 km
Fuel filter30,000 km
Accessory belt90,000 km
Coolant5 лет or 90,000 km

Watch-outs

Cons

  • Intake swirl flaps jam
  • Oil leaks quite common
  • Short-lived membrane of crankcase ventilation valve
  • Non-repairable piezo injectors

Strengths

Pros

  • High service life with proper maintenance
  • Provides excellent vehicle dynamics
  • Very reliable dual-row timing chain
  • Hydraulic lifters in cylinder head

Which cars used it?

Verified fitments; each row links to the related car report.

+29 more models

OM642 motoru: yorum, güvenilir mi, nasıl bir motor?

OM642, kaynaklarda öne çıkan High service life with proper maintenance ile anılan bir motor ailesidir; Intake swirl flaps jam dikkat edilmesi gereken nokta.

FAQ

OM642 güvenilir mi?+
Kaynaklarda öne çıkan artı: High service life with proper maintenance. Dikkat noktası: Intake swirl flaps jam. Tek bir hüküm yerine bakım geçmişi ve araç uygulamasıyla birlikte okumak daha güvenli.
OM642 nasıl bir motor?+
OM642 için kaynaklarda sık geçen çerçeve: High service life with proper maintenance; diğer yandan Intake swirl flaps jam. Ayrıntılar aşağıdaki artı/eksi ve sorun bölümlerinde.
OM642'da bilinen sorunlar neler?+
Bilinen sorun başlıklarından örnekler: Oil cooler leaks; Fuel system issues; Swirl flap problems.
How long does the OM642 engine last?+
OEM life note: not limited. Often cited in practice: 400,000 km. Treat mileage claims alongside service history and known issue themes.
Is the OM642 chain- or belt-driven?+
Timing type: chain. Tensioners, vanos/phasers, and oil quality matter.
Which cars used the OM642?+
Example fitments: Chrysler 300 3.0 24V CRD (2006–2010); Mercedes-Benz C Serisi C300 (2012–2014); Mercedes-Benz C Serisi C320 (2006–2007); Mercedes-Benz Clk CLK 320 CDI (2005–2009). Full list is in the applications section below.
How does Carbeak gather engine data?+
Pros, cons, and issue notes are compiled from OEM service notes and independent expert assessments. Fitments come from verified application records; thin families are not published.

Engine pros, cons, and issue notes are compiled from OEM service notes and independent expert assessments. Fitments come from verified application records; thin families are not published.

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