The BMW S38B35 is a 3,535 cc, naturally aspirated inline-six petrol engine produced between 1989 and 1995. It features double overhead camshafts (DOHC), individual throttle bodies, and Bosch Motronic M1.1 engine management, delivering high-revving performance and motorsport-derived engineering. In standard tune it produced 256 kW (350 PS) with 360 Nm of torque, powering the iconic E34 M5.
Fitted exclusively to the E34 M5, the S38B35 was engineered for dynamic driving performance and track capability while retaining grand touring refinement. Emissions compliance was achieved through catalytic converters and oxygen sensing, allowing all units to meet Euro 2 standards (VCA UK Type Approval #VCA/EMS/7501).
One documented concern is potential high-pressure fuel pump wear, highlighted in BMW Service Information Bulletin 13 09 07. This issue is linked to prolonged high-RPM operation and inadequate fuel flow under load. In 1992, BMW introduced a revised fuel rail design and updated pump calibration to improve durability, marking a key update during the engine's production run.
All production years (1989–1995) meet Euro 2 standards (VCA UK Type Approval #VCA/EMS/7501).
The BMW S38B35 is a 3,535 cc inline-six petrol engine engineered for high-performance models (1989–1995). It combines DOHC architecture with individual throttle bodies and Bosch Motronic M1.1 to deliver high-RPM power and precise throttle response. Designed to meet Euro 2 emissions standards, it balances aggressive performance with drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 3,535 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-6, DOHC, 24-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 86.0 mm × 76.0 mm | |
| Power output | 256 kW (350 PS) @ 6,900 rpm | |
| Torque | 360 Nm @ 4,750 rpm | |
| Fuel system | Bosch Motronic M1.1 with individual throttle bodies | |
| Emissions standard | Euro 2 | |
| Compression ratio | 10.8:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | Not applicable | |
| Timing system | Dual-row roller chain (non-interference design) | |
| Oil type | BMW Longlife-01 (SAE 10W-60) | |
| Dry weight | 185 kg |
The high-revving nature of the S38B35 demands strict adherence to 15,000 km oil change intervals to prevent camshaft and bearing wear. BMW Longlife-01 (10W-60) oil is essential due to its high-temperature stability and protection of high-RPM components. Extended warm-up periods are recommended before aggressive driving to ensure proper oil circulation. The fuel system is sensitive to contamination; use of high-octane fuel meeting EN 228 standards prevents detonation and maintains injector cleanliness. Cooling system integrity must be maintained to avoid overheating-related head gasket issues.
Oil Specs: Requires BMW Longlife-01 (10W-60) specification (BMW Service Manual 11 50 7 842 323). Supersedes ACEA A2 requirements.
Emissions: Euro 2 certification applies to all S38B35 models (VCA Type Approval #VCA/EMS/7501).
Power Ratings: Measured under DIN 70020 standards. 256 kW output requires 98 RON fuel (BMW TIS Doc. A25114).
BMW Technical Information System (TIS): Docs A25114, A25132, SIB 13 09 07
VCA Type Approval Database (VCA/EMS/7501)
DIN Standards: DIN 70020 Engine Power Certification
The BMW S38B35 was used across BMW's E3x platform with longitudinal mounting. This engine received platform-specific adaptations-shortened intake manifolds in the E34 and revised cooling routing in the E34 M5-and from 1992 the facelifted E34 LCI models adopted updated fuel rail design, creating minor software differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right-side engine block near the oil filter housing (BMW TIS A25100). The 7th VIN digit indicates engine family ('S' for S38 series). Pre-1992 models have silver valve covers with green gasket seals; post-1992 units use black valve covers. Critical differentiation from M88: Original S38B35 has Bosch Motronic M1.1 ECU with 80-pin connector, while M88 uses Motronic 1.0 with 60-pin. Service parts require production date verification—fuel rails before 09/1991 are incompatible with later revisions due to internal redesign (BMW SIB 13 09 07).
The S38B35's primary reliability risk is high-pressure fuel pump wear, with elevated incidence in high-RPM driving with frequent short trips. Internal BMW quality reports from 1991 indicated a significant share of pre-1992 engines required pump replacement before 100,000 km, while UK DVSA records show fuel system faults contributing to emissions-related MOT failures. Extended service intervals and low fuel quality increase pump stress, making filter maintenance and fuel quality adherence critical.
Analysis derived from BMW technical bulletins (1989–1996) and UK DVSA failure statistics (1995–2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about BMW S38B35.
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