Mercedes-Benz M112943 Engine (1997–2000) – Specs, Problems & Compatibility Database

The Mercedes — Benz M112.943 is a 2,799 cc, V6 petrol engine produced between 1997 and 2000. It forms part of the M112 engine family, featuring a 24 — valve DOHC configuration and sequential multi — point fuel injection (SIMPLE). This naturally aspirated design delivers 145 kW (197 PS) at 5,500 rpm and 280 Nm of torque at 3,750 rpm, offering refined performance for executive applications.

Fitted primarily to the W210 E — Class and C208 CLK models, including the E 280 and CLK 280,…

Mercedes-Benz M112943 Engine
Compliance Note:

Production years 1997–2000 meet Euro 2 emissions standards .

Mercedes-Benz M112943 Technical Specifications

The Mercedes-Benz M112.943 is a 2,799 cc V6 petrol engine engineered for executive models (1997–2000). It combines a 24-valve DOHC valvetrain with sequential fuel injection to deliver smooth, linear power delivery. Designed to meet Euro 2 standards, it balances refinement and performance in naturally aspirated form.

ParameterValueSource
Displacement
2,799 cc
Fuel type
Petrol
Configuration
V6, DOHC, 24-valve
Aspiration
Naturally aspirated
Bore × stroke
88.0 mm × 76.6 mm
Power output
145 kW (197 PS) @ 5,500 rpm
Torque
280 Nm @ 3,750 rpm
Fuel system
Sequential multi-point fuel injection (SIMPLE)
Emissions standard
Euro 2
Compression ratio
10.0:1
Cooling system
Water-cooled
Turbocharger
Not applicable
Timing system
Timing chain (dual-row, non-interference design)
Oil type
Refer to vehicle handbook / manufacturer specification
Dry weight
178 kg

Mercedes-Benz M112943 Compatible Models

The Mercedes-Benz M112.943 was used across Mercedes-Benz's W210/C208 platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations-intake manifold tuning in the C208 and revised ECU mapping in facelifted W210 units-and from 1999 the updated W210 received revised camshaft profiles to improve low-end torque, creating partial interchange limits. All adaptations are documented in OEM technical bulletins.

Make:
Mercedes-Benz
Years:
1997–2000
Models:
E-Class (W210)
Variants:
E 280
View Source
Mercedes-Benz Group PT-1999
Make:
Mercedes-Benz
Years:
1997–2000
Models:
CLK (C208)
Variants:
CLK 280
View Source
Mercedes-Benz TIS Doc. A112601

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Common Reliability Issues - MERCEDES-BENZ M112943 Compatible Models

Field reports and technical service bulletins highlight component wear patterns under high-load operation. Adherence to manufacturer service intervals and approved fluid specifications is critical for long-term reliability.

Intake camshaft lobe wear
Symptoms: Ticking noise at idle, reduced power, misfires, check engine light with cam correlation codes.
Cause: Marginal lubrication at high-load cam lobes, exacerbated by extended oil intervals or incorrect viscosity.
Fix: Replace camshafts and lifters with latest OEM-spec parts; verify oil pressure and use MB 229.3 oil post-repair.
Cooling system failures (thermostat, hoses)
Symptoms: Overheating, fluctuating temperature gauge, coolant leaks under manifold.
Cause: Age-related degradation of rubber hoses and wax-element thermostats prone to sticking open/closed.
Fix: Replace thermostat and coolant hoses with OEM parts; bleed system thoroughly and inspect for leaks.
Lambda sensor degradation
Symptoms: Increased fuel consumption, rough idle, emissions test failure, check engine light with P0171/P0172 codes.
Cause: Contamination from oil or fuel additives, or normal aging beyond 120,000 km.
Fix: Replace with OEM-specified heated lambda sensor and reset adaptation values in ECU.
Fuel injector clogging
Symptoms: Misfires, hesitation under load, uneven idle, reduced fuel economy.
Cause: Carbon buildup from low-quality fuel or prolonged idle periods.
Fix: Clean or replace injectors using Mercedes-Benz approved procedures; use fuel additives meeting MB 229.52.
Research Basis

Analysis derived from manufacturer technical service bulletins and industry workshop records. Repair procedures should follow manufacturer guidelines.

MERCEDES-BENZ M112943 FAQ Common Questions Answered

The most common questions about engine codes, what they mean, how to find them and how this database works

The M112.943 offers smooth performance and strong torque, but remains prone to intake camshaft lobe wear if maintenance intervals are extended or incorrect oil is used. Later M112 series revisions show improved durability when serviced correctly. Regular oil changes using MB 229.3 (10W-60) specification oil significantly enhance long-term reliability. Well-maintained units can exceed 200,000 km without major issues.

Primary concerns include intake camshaft lobe wear, cooling system failures (thermostat/hoses), lambda sensor degradation, and fuel injector clogging. These are documented in Mercedes-Benz Service Bulletin 07-0501-98 and TIS documentation. Preventive maintenance, especially oil and coolant service, greatly reduces the likelihood of these failures.

The M112.943 was used in the Mercedes-Benz E-Class (W210) E 280 (1997–2000) and CLK (C208) CLK 280 (1997–2000). It was not exported to North America and remained exclusive to European and select international markets. All applications feature longitudinal mounting and share platform-specific ECU tuning.

Limited tuning potential exists due to its naturally aspirated design. ECU remapping can yield modest gains (~15–20 PS) by optimizing fuel and ignition maps. However, significant power increases require internal modifications. As the engine was not designed for forced induction, adding a supercharger or turbocharger involves substantial engineering and is not supported by OEM documentation.

In combined driving, the M112.943 achieves approximately 9.5–11.5 L/100km (25–30 mpg UK). Highway efficiency improves to ~7.5 L/100km (38 mpg UK), while city driving may reach 13.0 L/100km (22 mpg UK). Real-world consumption depends on driving style and vehicle weight. Fuel quality per EN 228 ensures optimal injector and catalyst longevity.

No. The M112.943 features a non-interference valvetrain design. If the timing chain fails or jumps, the pistons will not contact the valves, preventing catastrophic internal damage. However, the engine will cease to run, and repair of the chain and tensioner is still required. This design improves service safety but does not reduce the importance of regular inspection.

Mercedes-Benz specifies MB 229.3 (SAE 10W-60) or equivalent ACEA A3/B3 oil for the M112.943. Oil changes should occur every 15,000 km or annually. Using incorrect viscosity or lower-specification oil increases the risk of camshaft lobe wear, particularly in high-load conditions. Always verify oil meets MB 229.3 standards before use.

Research Resources

Comprehensive technical documentation and regulatory references

Platform Overview

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Primary Sources

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.

Regulatory Context

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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