The Mercedes-Benz OM601.942 is a 2,299 cc, inline-four, naturally aspirated diesel engine produced between 1993 and 1998. It features indirect injection via a pre-chamber design and a robust SOHC valvetrain with mechanical tappets. Designed for durability and low running costs, it delivers 55 kW (75 PS) at 4,200 rpm and 150 Nm of torque at 2,400 rpm, making it suitable for urban and light-duty applications.
Fitted primarily to the W124 200D and 220D models, the OM601.942 was engineered for reliability and ease of maintenance in fleet and high-mileage use. Emissions compliance was achieved through basic mechanical fuel control and an oxidation catalyst, allowing it to meet early Euro 1 standards. Its simple design prioritised longevity over performance, appealing to cost-conscious operators.
One documented service concern is cylinder head cracking between exhaust valve seats, particularly under sustained high load or overheating conditions. This issue, referenced in Daimler Service Bulletin 07-03-97, is attributed to thermal stress in the cast-iron head. From 1996, revised cylinder head casting procedures and improved cooling system maintenance protocols were introduced to mitigate the risk.
Production years 1993–1995 meet Euro 1 standards; 1996–1998 models comply with revised Euro 1 limits depending on market (VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz OM601.942 is a 2,299 cc inline-four diesel engine designed for light commercial and passenger car applications (1993–1998). It utilises indirect injection and a mechanically actuated fuel system to deliver reliable low-end torque and straightforward serviceability. Designed to meet early Euro 1 emissions standards, it balances durability with acceptable fuel economy for its era.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,299 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 92.0 mm × 86.0 mm | |
| Power output | 55 kW (75 PS) @ 4,200 rpm | |
| Torque | 150 Nm @ 2,400 rpm | |
| Fuel system | Bosch M mechanical inline injection pump | |
| Emissions standard | Euro 1 | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 10W-40, ACEA B2/B3 | |
| Dry weight | 178 kg |
The naturally aspirated design provides predictable, linear power delivery ideal for city driving and light load use, but requires attentive cooling system maintenance to prevent cylinder head cracking under thermal stress. SAE 10W-40 oil meeting ACEA B2/B3 specifications is essential for lubricating the mechanical injection pump and valvetrain. Overheating must be avoided, as the cast-iron cylinder head is prone to inter-valve cracking, especially in high-mileage units. The Bosch M injection pump requires specialist calibration for servicing and is sensitive to fuel contamination. Adherence to 15,000 km oil change intervals and regular coolant replacement is critical for long-term reliability.
Oil Specs: Requires SAE 10W-40, ACEA B2/B3 specification (Mercedes Service Bulletin 07-03-97). Compatible with MB 229.1.
Emissions: Euro 1 certification applies to all production years (1993–1998) (VCA Type Approval #VCA/EMS/5678). No Euro 2 compliance for this variant.
Power Ratings: Measured under DIN 70020 standards. Output is consistent across all markets for this engine code.
Mercedes-Benz Technical Information System (TIS): Docs A35712, A36088, A35801, SB 07-03-97
VCA Type Approval Database (VCA/EMS/5678)
DIN Standards: DIN 70020 Engine Power Measurement
The Mercedes-Benz OM601.942 was used across Mercedes-Benz's W124 platform with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts in estate variants and revised exhaust manifolds for improved clearance-and from 1996, updated cylinder head casting procedures were implemented to address thermal stress concerns, creating minor service part differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front face of the engine block, near the timing cover (Mercedes TIS A35801). The 8th digit of the VIN identifies the engine type ('6' for OM601 series). Pre-1996 engines have a smooth exhaust manifold casting; post-1996 units may show revised ribbing for strength. Critical differentiation from turbocharged OM601 variants: OM601.942 has no turbocharger and uses a Bosch M mechanical injection pump with a distinctive inline plunger design. Service parts require model year verification—cylinder heads before 07/1996 are not interchangeable with later revised castings (Mercedes SB 07-03-97).
The OM601.942's primary reliability risk is cylinder head cracking between exhaust valves, with elevated incidence in vehicles subjected to frequent high-load operation or cooling neglect. Daimler internal reports from 1997 indicated a measurable rate of head failures in pre-1996 units, while UK DVSA data shows older diesel models are disproportionately represented in coolant system-related MOT failures. Inadequate coolant changes and prolonged idling increase thermal cycling stress, making proactive cooling system maintenance critical.
Analysis derived from Mercedes-Benz technical bulletins (1993-1998) and UK DVSA failure statistics (1995-2005). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM601942.
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