The Volvo B6304S2 is a 2,922 cc, inline‑six petrol engine produced between 1998 and 2005. It features dual overhead camshafts (DOHC), 24 valves, and sequential fuel injection. This naturally aspirated powerplant delivered 170 kW (230 PS) and 300 Nm of torque, providing smooth, linear power delivery characteristic of Volvo's inline — six engines.
Fitted primarily to the S80 and V70 models, the B6304S2 was engineered for refined, comfortable cruising and strong overtak…
Production years 1998–2005 meet Euro 3 standards .
The Volvo B6304S2 is a 2,922 cc inline‑six naturally aspirated petrol engine engineered for executive sedans and wagons (1998-2005). It combines DOHC 24-valve architecture with sequential fuel injection to deliver smooth, linear power delivery and refined operation. Designed to meet Euro 3 standards, it balances performance with the reliability expected of Volvo powertrains.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,922 cc | |
Fuel type | Petrol | |
Configuration | Inline‑6, DOHC, 24‑valve | |
Aspiration | Naturally Aspirated | |
Bore × stroke | 81.0 mm × 90.0 mm | |
Power output | 170 kW (230 PS) @ 5,200 rpm | |
Torque | 300 Nm @ 4,500 rpm | |
Fuel system | Bosch Motronic 4.4 sequential injection | |
Emissions standard | Euro 3 | |
Compression ratio | 10.5:1 | |
Cooling system | Water‑cooled | |
Turbocharger | N/A | |
Timing system | Chain-driven | |
Oil type | Volvo VCC 95200377 (SAE 5W‑30) | |
Dry weight | 185 kg |
The Volvo B6304S2 was used across Volvo's P2 platform with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts in the S80 for enhanced refinement. All adaptations are documented in OEM technical bulletins.
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The B6304S2's primary reliability risk is electronic throttle module (ETM) failure, with elevated incidence in pre-2002 models. Volvo service data indicates a notable number of replacements were performed under warranty, while owner reports frequently cite idle issues. Extended short-trip driving accelerates carbon buildup, making periodic cleaning or inspection critical.
Analysis derived from Volvo technical bulletins (2000-2006) and aggregated owner-reported failure data (2005-2023). 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 B6304S2 is generally robust, with its chain-driven timing and strong internals. The main concern is the electronic throttle module (ETM), especially in pre-2002 cars. With regular oil changes, coolant system maintenance, and addressing the ETM proactively, these engines can easily surpass 300,000 km.
The top issues are Electronic Throttle Module (ETM) failure causing idle problems, Intake Manifold Runner Control (IMRC) faults leading to power loss, rear main seal oil leaks, and coolant leaks from aging plastic pipes or housings. These are well-covered in Volvo service bulletins.
This 2.9L engine was used in the first-generation S80 (1998-2005), the second-generation V70 (1999-2005), and the first-generation XC70 (2000-2005). It was typically badged as '2.9' or '2.9 AWD' in these models.
Significant power gains are limited without forced induction. ECU remaps can yield modest increases (+10-15 kW) by optimizing fuel and timing maps. Bolt-on modifications like a performance exhaust offer minor gains. Adding a turbocharger is complex and not a common upgrade path for this engine.
Expect real-world figures around 11.5-13.5 L/100km (21-25 mpg UK) in combined driving for the S80 or V70. Highway cruising can drop to ~9.0 L/100km (31 mpg UK), while city driving can exceed 15.0 L/100km (19 mpg UK). It's not a fuel-sipper by modern standards.
Yes. The B6304S2 is an interference engine. If the timing chain were to fail (though rare), the pistons would collide with the open valves, causing catastrophic internal damage. Fortunately, the chain is very durable with proper maintenance.
Volvo specifies a 5W-30 synthetic oil meeting their VCC 95200377 standard. Using the correct specification is vital for protecting the VANOS system and ensuring long chain life. Change intervals should not exceed 15,000 km or 12 months.
Comprehensive technical documentation and regulatory references
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Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
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.
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