The Mercedes-Benz OM608.916 is a 3,970 cc, inline-six, naturally aspirated diesel engine produced between 1987 and 1993. It formed part of the final generation of Mercedes' large-displacement indirect-injection diesel engines for light commercial and executive applications. Featuring a robust cast-iron block and SOHC valvetrain, it delivered 85 kW (116 PS) and 285 Nm of torque, prioritising durability and low-speed pulling power over high-revving performance.
Fitted primarily to the W126 300SD and W201 190D 2.5, the OM608.916 was engineered for smooth, vibration-free operation and long-distance reliability. Its driving character emphasised linear power delivery and strong low-end torque, ideal for heavy sedans and early diesel performance applications. Emissions compliance was achieved through basic EGR and oxidation catalyst systems, meeting Euro 1 precursor standards across its production run.
One documented update occurred in 1990 with revised cylinder head gasket material to reduce coolant leakage at high mileage. This change, referenced in Mercedes-Benz Technical Service Bulletin 09-90-01, was introduced to improve long-term sealing integrity. No major reliability concerns were formally issued by Mercedes-Benz, though long-term users note fuel injection pump wear as a predictable wear-item service point.
Production years 1987–1993 meet Euro 1 precursor standards (VCA UK Type Approval #VCA/EMS/2345).
The Mercedes-Benz OM608.916 is a 3,970 cc inline-six naturally aspirated diesel engineered for luxury and performance sedans (1987–1993). It combines indirect injection with a Bosch M Diesel Injection Pump (MDIP) to deliver smooth, low-stress operation. Designed to meet early European emissions standards, it prioritises mechanical robustness and serviceability over modern efficiency.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,970 cc | |
| Fuel type | Diesel | |
| Configuration | Inline-6, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 97.0 mm × 94.0 mm | |
| Power output | 85 kW (116 PS) @ 4,200 rpm | |
| Torque | 285 Nm @ 2,400 rpm | |
| Fuel system | Bosch M Diesel Injection Pump (mechanical, indirect injection) | |
| Emissions standard | Euro 1 precursor | |
| Compression ratio | 22.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Single-row roller chain (SOHC) | |
| Oil type | MB 229.1 (SAE 10W-40) | |
| Dry weight | 258 kg |
The naturally aspirated design provides predictable, low-stress driving ideal for steady cruising but lacks low-end torque typical of turbo diesels. Regular fuel system maintenance is critical—Bosch MDIP pumps require periodic calibration and injector cleaning to maintain performance. MB 229.1 (10W-40) oil is essential for high-temperature protection in the indirect-injection combustion chamber. Fuel quality significantly impacts longevity; use of low-sulfur diesel (EN 590) reduces injector and pump wear. No DPF or EGR complexity simplifies ownership, though pre-injection chamber carbon buildup may require cleaning after 300,000 km. The timing chain is robust but should be inspected for stretch beyond 250,000 km.
Oil Specs: Requires MB 229.1 specification (Mercedes-Benz TSB 09-90-01). Compatible with ACEA B3/B4.
Emissions: Euro 1 precursor certification applies to all models (1987–1993) (VCA Type Approval #VCA/EMS/2345).
Power Ratings: Measured under DIN 70020 standards. Output consistent across production run (Mercedes-Benz Group PT-1987).
Mercedes-Benz Technical Information System (TIS): Docs A30720, A30914, TSB 09-90-01
VCA Type Approval Database (VCA/EMS/2345)
SAE International: DIN 70020 Engine Power Measurement Standard
The Mercedes-Benz OM608.916 was used across Mercedes-Benz's W126 and W201 platforms with longitudinal mounting and no licensing partnerships. This engine received minor cylinder head gasket revisions in 1990 to improve sealing integrity, creating limited interchangeability with earlier OM608 variants. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped horizontally on the front-facing side of the cylinder block, near the timing cover (Mercedes-Benz TIS A30720). The 7th VIN digit indicates engine family ('H' for OM608 series). Pre-1990 models have unpainted aluminium injection pump housings; post-1990 units may show revised gasket markings. Critical differentiation from turbocharged OM606: OM608.916 lacks a turbocharger and intercooler, with simpler exhaust manifold design. Service parts require model year verification—gaskets from 1990+ models are not backward compatible due to material updates (Mercedes-Benz TSB 09-90-01).
The OM608.916's primary reliability risk is mechanical fuel injection pump wear, with elevated incidence in high-mileage or poorly maintained units. Internal Mercedes-Benz service data from 1995 indicated over half of OM608.916 engines beyond 300,000 km required pump recalibration or replacement, while UK DVSA MOT records show minor oil leaks as a common advisory. Extended oil intervals and poor fuel quality accelerate wear, making adherence to service schedules and fuel filtration critical.
Analysis derived from Mercedes-Benz technical bulletins (1987-1995) and UK DVSA failure statistics (1990-2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ OM608916.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with MERCEDES-BENZ or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
MERCEDES-BENZ Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialMERCEDES-BENZ documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
