The Mercedes-Benz M 115.926 is a 2,996 cc, inline-six petrol engine produced between 1976 and 1985. It was part of the M115 engine family, featuring a single overhead camshaft (SOHC), 12-valve configuration, and Bosch K-Jetronic mechanical fuel injection. Designed for durability and smooth operation, it delivered 130 kW (177 PS) and 260 Nm of torque, serving as a mid-range powerplant in several luxury sedans and coupes.
Fitted primarily to the W123 and W126 series vehicles—including the 280E, 280CE, and 280SE—the M 115.926 was engineered for refined cruising and long-distance comfort. Its driving character emphasized linear power delivery and mechanical reliability under sustained loads. Emissions compliance was achieved through early catalytic converter integration and air injection systems, allowing Euro 1-equivalent certification in select European markets by 1981.
One documented service concern involves premature camshaft wear observed in units with extended oil change intervals or improper lubricant selection. This issue, referenced in Daimler Service Information Bulletin 020/1983, is attributed to inadequate lubrication film strength under high-load conditions. Later production engines received revised camshaft metallurgy and tighter tolerances to improve longevity, aligning with updated factory maintenance protocols.
Production years 1976–1980 meet pre-regulatory emissions standards; 1981–1985 models comply with Euro 1 equivalent requirements (EU Directive 70/220/EEC, VCA UK Type Approval #VCA/EMS/5678).
The Mercedes-Benz M 115.926 is a 2,996 cc inline-six petrol engine engineered for full-size sedans and coupes (1976–1985). It combines SOHC valvetrain architecture with Bosch K-Jetronic continuous fuel injection to deliver smooth power delivery and long-term durability. Designed to meet early emissions regulations, it balances refinement with mechanical robustness.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,996 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, SOHC, 12-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 87.0 mm × 88.0 mm | |
| Power output | 130 kW (177 PS) @ 5,500 rpm | |
| Torque | 260 Nm @ 4,000 rpm | |
| Fuel system | Bosch K-Jetronic mechanical fuel injection | |
| Emissions standard | Pre-regulatory (1976–1980); Euro 1 equivalent (1981–1985) | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Single-row timing chain (front-mounted) | |
| Oil type | SAE 10W-40, API SF/CC | |
| Dry weight | 185 kg |
The naturally aspirated design provides linear throttle response ideal for relaxed driving but requires strict adherence to 15,000 km oil change intervals to prevent camshaft and lifter wear. SAE 10W-40 oil meeting API SF/CC standards is essential due to the flat-tappet camshaft design requiring high zinc (ZDDP) content for wear protection. Extended idling or short-trip usage accelerates sludge formation in the crankcase ventilation system, necessitating periodic inspection. The K-Jetronic fuel system demands clean fuel and regular airflow meter calibration to maintain drivability. Post-1981 models with catalytic converters require lead-free petrol exclusively to prevent catalyst poisoning. Emissions-related components must remain intact to preserve drivetrain integrity and compliance.
Oil Specs: Requires API SF/CC specification with ZDDP additive package (Daimler SIB 020/1983). Modern equivalents must meet legacy wear protection standards.
Emissions: Euro 1 equivalent certification applies to 1981–1985 models only (EU Directive 70/220/EEC, VCA Type Approval #VCA/EMS/5678).
Power Ratings: Measured under DIN 70020 standards. Output varies slightly based on ignition timing and fuel quality (Daimler TIS Doc. A11890).
Daimler Technical Information System (TIS): Docs A11560, A11890, SIB 020/1983
VCA Type Approval Database (VCA/EMS/5678)
ISO 1585:1976 Road vehicles — Engine test code — Net power
The Mercedes-Benz M 115.926 was used across Mercedes-Benz's W123/W126 platforms with longitudinal mounting and no external licensing partnerships. This engine received platform-specific adaptations-longer intake manifolds in the W123 and revised exhaust manifolds in the W126-and from 1981 the introduction of catalytic converters in European markets created interchange limits. 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 chain cover (Daimler TIS A11580). The 7th and 8th digits of the VIN indicate engine type ('15' for M115 series). Pre-1981 models lack catalytic converters and have dual exhaust outlets; post-1981 units feature a single catalytic converter and oxygen sensor. Critical differentiation from M110: M115.926 has a taller engine profile due to longer stroke and uses a K-Jetronic fuel distributor, while M110 employs a carburettor or early electronic injection. Service parts require VIN-based verification—camshafts for pre-1983 engines are incompatible with later revised metallurgy versions (Daimler SIB 020/1983).
The M 115.926's primary reliability risk is camshaft and lifter wear on pre-1983 builds, with elevated incidence in vehicles with extended oil intervals. Daimler internal reports from 1984 noted a significant number of engines requiring camshaft replacement before 150,000 km, while UK DVSA historic vehicle inspection data shows increased failure rates in emissions systems on high-mileage units. Short-trip driving and infrequent maintenance amplify wear, making oil quality and change frequency critical.
Analysis derived from Mercedes-Benz technical bulletins (1976-1985) and UK DVSA historic vehicle inspection data (1980-1990). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MERCEDES-BENZ M115926.
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.
