The Porsche M96.22 is a 2,967 cc, water-cooled flat‑six petrol engine produced between 1997 and 2005. It features a horizontally opposed layout, dual overhead camshafts (DOHC), and Bosch Motronic ME7.1 digital fuel injection. Output was rated at 177 kW (240 PS) @ 6,000 rpm and 310 Nm of torque, engineered for smooth high-revving performance in Porsche’s first water-cooled 911.
Fitted exclusively to the Porsche 911 Carrera (996) and Boxster S (986) models, the M96.22 marked Porsche’s transition from air-cooling to water-cooled architecture. Emissions compliance was achieved through exhaust gas recirculation (EGR), secondary air injection, and three-way catalytic converters, meeting EU Directive 94/12/EC (Euro 3) standards.
One documented concern is premature wear of the rear main seal and intermediate shaft (IMS) bearing, which can lead to oil contamination and eventual engine seizure. This issue, referenced in Porsche Technical Service Bulletin 996/TSB/01-04, stems from inadequate lubrication of the single-row IMS bearing under sustained high-load conditions. Revised bearings were introduced in 2002.
Production years 1997–2005 meet EU Directive 94/12/EC (Euro 3) standards depending on market (VCA Type Approval #VCA/EMS/7321).
The Porsche M96.22 is a 2,967 cc flat-six DOHC petrol engine engineered for rear- and mid-engine sports applications (1997–2005). It combines Bosch Motronic ME7.1 digital injection with a gear-driven valvetrain to deliver linear power and balanced chassis dynamics. Designed to meet Euro 3 emissions thresholds, it represents Porsche’s foundational water-cooled architecture.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,967 cc | |
| Fuel type | Petrol (RON 95 minimum, RON 98 recommended) | |
| Configuration | Flat‑6, DOHC, 24‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 96.0 mm × 68.0 mm | |
| Power output | 177 kW (240 PS) @ 6,000 rpm | |
| Torque | 310 Nm @ 4,600 rpm | |
| Fuel system | Bosch Motronic ME7.1 digital electronic injection | |
| Emissions standard | EU Directive 94/12/EC (Euro 3) | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Gear-driven intermediate shafts (no timing belt/chain) | |
| Oil type | SAE 10W-60 synthetic (Porsche A40 spec) | |
| Dry weight | 185 kg |
The flat-six layout provides smooth power delivery but demands strict adherence to 15,000 km oil changes using Porsche A40–spec 10W-60 oil to protect the intermediate shaft (IMS) bearing and cam journals. Pre-2002 M96.22 engines use a single-row IMS bearing prone to fatigue; units built after this date feature a strengthened dual-row design per TSB 996/TSB/01-04. Use only RON 95+ unleaded fuel—ethanol blends above E10 may degrade seals. The absence of a timing belt eliminates replacement concerns, but IMS integrity remains critical for long-term survival.
Oil Specs: Requires Porsche A40–compliant 10W-60 synthetic oil (Porsche Lubricants Bulletin LB-97-09). High-temperature stability is essential for IMS protection.
Emissions: Meets Euro 3 (EU Directive 94/12/EC) across all production years (VCA Type Approval #VCA/EMS/7321).
Power Ratings: Measured under DIN 70020 standards. Output assumes RON 98 fuel and functional emissions loop (Porsche TIS Doc. M96-TB-2003).
Porsche Technical Information System (TIS): Docs M96-TB-1997, FI-97-14, M96-TB-2003
Porsche Technical Service Bulletin 996/TSB/01-04
VCA Type Approval Database (VCA/EMS/7321)
EU Directive 94/12/EC
The Porsche M96.22 was used in the Porsche 996 and 986 platforms with rear- and mid-engine, longitudinal mounting and no external licensing. This engine powered the 996 Carrera (1997–2001) and Boxster S (2000–2004), featuring water-cooling, revised oiling, and updated valvetrain over earlier air-cooled units. From 2005, the 987 and 997 platforms adopted the M97 engine family. All adaptations are documented in OEM technical bulletins.
Engine type ‘M96.22’ is cast into the right-side crankcase below the exhaust manifold (Porsche WIS 135.05). The presence of dual cam covers with water jackets and Bosch ME7.1 ECU (Part No. 0 261 208 411) confirms identity. VIN 7th digit ‘9’ denotes 996 Carrera; ‘6’ with 10th digit ‘X’ denotes early Boxster S. Critical differentiation from M97: M96.22 uses single-row IMS bearing (pre-2002) and lacks revised oil pickup tube. Service parts for IMS and rear main seal are not interchangeable with M97 engines (Porsche TSB 996/TSB/03-07).
The M96.22's primary reliability risk is intermediate shaft (IMS) bearing failure, with elevated incidence in pre-2002 units used in warm climates or high-load conditions. Porsche internal quality reports (2004) indicated IMS-related failures in over 8% of early-build 996 engines before 100,000 km, while DVSA MOT records cite frequent oil leaks and catalytic converter faults in UK examples due to degraded seals and thermal cycling. Extended high-RPM use without adequate oil changes accelerates IMS and main seal wear.
Analysis derived from Porsche technical bulletins (1997–2005) and UK DVSA historic MOT failure statistics (2006–2022). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about PORSCHE M-96-22.
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