Naturally Aspirated (OM422) / Turbocharged (OM422A) / Intercooled (OM422LA) Liquid-Cooled Firing Order 1-5-7-2-6-3-4-8 2. Tightening Torques & Fastener Specs
A belt-driven centrifugal water pump circulates coolant through the cylinder block and heads. Dual wax-element thermostats regulate operating temperatures.
Bleed the fuel system thoroughly using the hand primer pump before attempting to start the engine. 5. Cylinder Head and Wet Sleeve Liners
| Component | Torque (Nm) | Angle (if any) | | --- | --- | --- | | Cylinder head bolts (M16) | 100 Nm + 90° + 90° + 90° | Final 90° in sequence | | Connecting rod bolts | 60 Nm + 90° | Single use | | Main bearing cap bolts | 120 Nm + 90° | Replace bolts | | Flywheel to crankshaft | 200 Nm + 180° | Use thread locker | | Injection pump drive gear | 100 Nm | – |
Defective glow plugs; incorrect injection pump timing; low compression. om422 engine workshop manual
It was designed for "low-end grunt," producing massive pulling power at low RPMs (e.g., peak torque at just 1,200 RPM). Naturally aspirated (approx. 280 hp). Turbocharged. Turbocharged and Intercooled (reaching up to 435 hp). Why the Manual Matters Today The "story" continues today in the world of expedition vehicles
Pressure test the cooling system, check individual head gaskets, examine liner seals.
Align the pointer with the required degree mark on the compression stroke of Cylinder 1.
The manual details the following critical specifications for the OM422: Bleed the fuel system thoroughly using the hand
Up to 1400 Nm depending on the turbocharger configuration Idle Speed: 550 – 600 RPM Maximum Rated Speed: 2300 RPM 2. Tightening Torques & Fastener Specifications
Without an ECU (Engine Control Unit) to fail, it can be fixed with basic tools and a good manual in the middle of a desert. Agricultural Legacy: Beyond trucks, these engines powered the CLAAS Commandor
The OM422 manual is often grouped with its siblings, the V10 OM423 and V12 OM424, as they share a modular design philosophy that dominated the heavy transport and industrial sectors for years. These manuals are preserved by dedicated groups like the Barrington Diesel Club and found through specialty retailers like Agrimanuals or VintageManuals .
This section covers the removal, inspection, and installation of the cylinder heads. It was designed for "low-end grunt," producing massive
: Offers a 256-page OM421/422/423 Workshop Manual in PDF format.
: Guidelines for oil changes, fuel filter renewals, and V-belt tensioning. Critical Torque Specifications
The following sections are crucial for overhaul and routine maintenance, which you can find in specialized Mercedes Benz OM421/422/423 Manuals : A. Cylinder Head and Valve Train