The Porsche M 96.04 is a 2,967 cc, water‑cooled flat‑six petrol engine produced between 1997 and 2001. It featured Bosch Motronic 5.2 electronic fuel injection, dual overhead camshafts (DOHC), and a 24‑valve layout. In the 996 Carrera it delivered 221 kW (300 PS) and 350 Nm of torque, with a redline of 6,800 rpm.
Fitted exclusively to the 996 — generation 911 Carrera and Carrera 4, the M 96.04 marked Porsche’s transition from air‑ to water‑cooling. Emissions compliance was a…
Production years 1997–2001 meet Euro 3 emissions standards under EU Directive 98/69/EC .
The Porsche M 96.04 is a 2,967 cc flat‑six petrol engine engineered for the 996-generation 911 (1997–2001). It combines Bosch Motronic 5.2 engine management with DOHC architecture and full water-cooling to deliver smooth power delivery and compliance with Euro 3 emissions. Designed as Porsche’s first water-cooled flat-six, it balances modern drivability with traditional 911 character.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,967 cc | |
Fuel type | Petrol (Unleaded) | |
Configuration | Flat‑6, DOHC, 24‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 96.0 mm × 68.0 mm | |
Power output | 221 kW (300 PS) | |
Torque | 350 Nm @ 4,600 rpm | |
Fuel system | Bosch Motronic 5.2 sequential electronic injection | |
Emissions standard | Euro 3 | |
Compression ratio | 11.3:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Chain-driven DOHC with hydraulic tensioners | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 175 kg |
The Porsche M 96.04 was used exclusively in Porsche's 996 platform with rear-engine, longitudinal mounting and no external licensing. This engine powered base Carrera and Carrera 4 models, differing only in AWD drivetrain integration. From mid-1999, revised cylinder head castings were introduced to address porosity issues, creating minor service distinctions. All adaptations are documented in OEM technical bulletins.
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The M 96.04's primary reliability risk is cylinder head porosity or cracking near exhaust ports, with elevated incidence in early-build (1997–1999) examples exposed to repeated thermal cycling. Porsche internal analysis from 2000 indicated less than 3 % field incidence, but UK specialist data shows higher rates in vehicles subjected to track use or coolant neglect. Extended coolant service intervals accelerate corrosion, making fluid quality and replacement adherence critical.
Analysis derived from Porsche technical bulletins (1997–2001) and UK specialist workshop data (2001–2023). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M 96.04 is generally robust but requires attentive maintenance. Early engines (1997–1999) have a higher risk of cylinder head porosity—proactive pressure testing is recommended. Using correct 10W-60 synthetic oil and replacing coolant every 4 years ensures longevity. Well-maintained examples can exceed 180,000 km.
Top issues include cylinder head porosity (early builds), rear main seal leaks, IMS bearing wear, and coolant hose degradation. All are manageable with proper service. Porsche documented the head issue in SIB 996/02/99, and IMS concerns are widely recognized in the enthusiast community.
Exclusively the 996-generation 911 Carrera and Carrera 4 (1997–2001). It was Porsche’s first water-cooled flat-six, replacing the air-cooled 993. No Turbo, GT3, or Boxster models used this exact code. All are rear-engine, rear- or all-wheel-drive coupés or cabriolets.
Aftermarket ECU tuning is common on the M-96-04 platform, but increasing boost or altering engine parameters accelerates component wear, impacts emissions compliance, and may void vehicle warranties. Any modifications should be evaluated carefully by a qualified specialist.
Approximately 14.2 L/100km (city) and 9.0 L/100km (highway), or ~26 mpg UK combined. Aggressive driving can exceed 17 L/100km. The Bosch Motronic 5.2 system is efficient for a 3.0L flat-six of its era.
Yes. The M 96.04 is an interference engine—pistons and valves occupy the same space if timing fails. Chain-driven DOHC with hydraulic tensioners is generally robust, but timing failure can cause severe internal damage.
Porsche specifies 10W‑60 synthetic oil meeting ACEA A3/B3 standards (e.g., Porsche Longlife). Change oil every 10,000 km or annually to protect the valvetrain and IMS bearing.
Comprehensive technical documentation and regulatory references
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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
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VCA Certification Portal
Type-approval guidance and documentation.
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