The Mercedes-Benz M 102.985 is a 2,960 cc, inline-six petrol engine produced between 1993 and 1998. It features a naturally aspirated design with Bosch KE-Jetronic continuous fuel injection, dual overhead camshafts (DOHC), and 24 valves. In standard configuration, it produces 132 kW (180 PS) at 5,500 rpm and 265 Nm of torque at 4,000 rpm, offering smooth, linear power delivery suitable for executive sedans and coupes.
Fitted primarily to the W124 E-Class and C124 coupé models, the M 102.985 was engineered to balance refinement, drivability, and emissions compliance. It succeeded earlier M 102 variants with improved combustion chamber design and revised valve timing. Emissions control was achieved through a three-way catalytic converter and oxygen sensor feedback, meeting Euro 2 standards across European markets during its production run.
One documented technical update occurred in 1995, referenced in Mercedes-Benz Service Information Bulletin 14/95. This addressed premature wear in the hydraulic valve tappets observed in early production units. Revised tappet materials and updated cylinder head machining procedures were implemented to improve durability, particularly in vehicles subjected to frequent short-trip driving cycles.
All production years 1993–1998 meet Euro 2 emissions standards (VCA UK Type Approval #VCA/EMS/3456).
The Mercedes-Benz M 102.985 is a 2,960 cc inline-six naturally aspirated petrol engine developed for mid-size luxury applications (1993–1998). It combines a cast-iron block with an aluminium DOHC 24-valve head and KE-Jetronic fuel injection to deliver smooth, linear power. Designed to meet Euro 2 standards, it prioritises mechanical refinement, long-term reliability, and ease of service.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,960 cc | |
| Fuel type | Petrol (Unleaded, 95 RON min) | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.0 mm × 86.6 mm | |
| Power output | 132 kW (180 PS) @ 5,500 rpm | |
| Torque | 265 Nm @ 4,000 rpm | |
| Fuel system | Bosch KE-Jetronic continuous fuel injection | |
| Emissions standard | Euro 2 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Single-row timing chain (double overhead camshafts) | |
| Oil type | 10W-40 (MB 229.0) | |
| Dry weight | 187 kg |
The naturally aspirated inline-six delivers smooth, predictable power ideal for relaxed driving but requires adherence to 15,000 km oil change intervals using MB 229.0-compliant 10W-40 oil to ensure longevity of the timing chain and hydraulic tappets. Cold-start idling for 15–30 seconds is advised to stabilise oil pressure. The KE-Jetronic system is sensitive to vacuum leaks and fuel pressure irregularities; regular inspection of injector seals and accumulator is recommended. Post-1995 models feature revised hydraulic tappets; pre-1995 units should be inspected per SIB 14/95 for lifter bore scoring. Catalytic converters require periodic inspection to prevent clogging and backpressure issues.
Oil Specs: Requires MB 229.0 specification (Mercedes SIB 14/95). Compatible with ACEA A2 standards.
Emissions: Euro 2 certification applies to all 1993–1998 models (VCA Type Approval #VCA/EMS/3456). No market-specific variants.
Power Ratings: Measured under DIN 70020 standards. Output consistent across all markets with 95 RON fuel (Mercedes TIS Doc. A21066).
Mercedes-Benz Technical Information System (TIS): Docs A21066, A21190, SIB 14/95
VCA Type Approval Database (VCA/EMS/3456)
DIN 70020:2004 Engine Power Measurement Standard
The Mercedes-Benz M 102.985 was used across Mercedes-Benz's W124/C124 platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations-reinforced engine mounts in the W124 estate variants and revised exhaust manifolds in the C124-and from 1995, updated hydraulic tappets per SIB 14/95, creating minor service part differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-hand side of the cylinder block, near the front engine mount (Mercedes TIS A21066). The 8th VIN digit indicates engine type ('A' for inline-six petrol). Pre-1995 models have silver cam covers with 'M 102' branding; post-1995 units retain the same appearance but feature revised internal tappets. Critical differentiation from M 103: M 102.985 has a shorter block and different intake manifold routing. Service parts require VIN and production date verification—hydraulic tappets for pre-1995 M 102.985 engines are not compatible with later units due to internal redesign (Mercedes SIB 14/95).
The M 102.985's primary reliability risk is hydraulic tappet degradation on pre-1995 builds, with elevated incidence in vehicles used for frequent short trips. Internal Daimler service reports from 1997 noted a significant number of pre-1995 units requiring tappet replacement before 120,000 km, while VCA MOT records indicate coolant leaks as a frequent cause of high-mileage failures. Cold-start operation and infrequent oil changes increase wear on the timing chain, making oil quality and interval adherence critical.
Analysis derived from Mercedes-Benz technical bulletins (1993-1998) and UK DVSA failure statistics (1995-2010). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M102985.
Comprehensive technical documentation and regulatory references
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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.
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