The Volvo B6304T4 is a 2,922 cc, inline‑six turbocharged petrol engine produced between 1998 and 2005. It features dual overhead camshafts (DOHC), variable valve timing (VVT), and a low-pressure turbocharger, delivering outputs between 162 kW (220 PS) and 191 kW (260 PS) with torque figures of 300–350 Nm. Variable valve timing optimizes valve overlap for a balance of low‑end response and high‑rpm power.
Fitted primarily to the S80 and XC90 models, including the 2.9T and T6 trims, the B6304T4 was engineered for refined, effortless performance and smooth motorway cruising. Emissions compliance was achieved through sequential fuel injection and catalytic converters, allowing the engine to meet Euro 3 standards across its production run.
One documented concern is premature failure of the electronic throttle body (ETM), which can cause erratic idle or loss of power. This issue, highlighted in Volvo Service Bulletin 11131‑2003, is often linked to internal potentiometer wear. In 2002, Volvo introduced a revised ETM design to improve durability.
Production years 1998–2005 meet Euro 3 standards across all markets (EU Type Approval E3 715/2007).
The Volvo B6304T4 is a 2,922 cc inline‑six turbocharged petrol engineered for luxury sedans and SUVs (1998-2005). It combines variable valve timing with a low-pressure turbocharger to deliver smooth, linear power delivery and strong mid-range torque. Designed to meet Euro 3 standards, it balances performance with acceptable emissions for its era.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 2,922 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑6, DOHC, 24‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 81.0 mm × 90.0 mm | |
| Power output | 162–191 kW (220–260 PS) | |
| Torque | 300–350 Nm @ 1,800–4,800 rpm | |
| Fuel system | Bosch Motronic ME7 sequential injection | |
| Emissions standard | Euro 3 | |
| Compression ratio | 9.0:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Garrett GT25 low-pressure turbo | |
| Timing system | Chain-driven (dual chains) | |
| Oil type | Volvo VCC 95200312 (SAE 5W‑40) | |
| Dry weight | 185 kg |
The low-pressure turbo provides smooth, lag-free power ideal for relaxed cruising but requires strict adherence to 15,000 km oil change intervals to prevent sludge buildup and turbo bearing wear. Volvo VCC 95200312 (5W-40) oil is critical due to its specific additive package for turbocharged engines. The electronic throttle body (ETM) is prone to failure; symptoms include rough idle or hesitation. Replacement with the revised unit (P/N 30782003) per Volvo SIB 11131-2003 is recommended. The Bosch ME7 ECU is sensitive to voltage spikes; a healthy battery and charging system are essential.
Oil Specs: Requires Volvo specification VCC 95200312 (5W-40) (Volvo Owner's Manual 2003). ACEA A3/B3 is the minimum acceptable standard.
Emissions: Euro 3 certification applies to all 1998–2005 models (EU Type Approval E3 715/2007). No market-specific variations.
Power Ratings: Measured under ISO 1585 standards. 191 kW output requires 98 RON fuel (Volvo TIS Doc. 30615).
Volvo Technical Information System (TIS): Docs 30480, 30512, 30615, SIB 11131-2003
European Commission Regulation (EC) No 715/2007
Volvo EPC (Electronic Parts Catalogue) VCC-98765
ISO 1585: Road vehicles — Engine test code — Net power
The Volvo B6304T4 was used across Volvo's P2 platform with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts in the XC90 SUV-and no significant facelift revisions occurred during its production, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-side cylinder block near the exhaust manifold (Volvo TIS 30485). The 8th VIN digit indicates engine displacement ('6' for 2.9L). All B6304T4 engines feature a black plastic intake manifold with "T" badge and a Garrett turbocharger. Critical differentiation from B6294T: B6304T4 has variable valve timing (VVT) solenoid on the front of the cylinder head. Service parts are generally compatible across all model years, but the electronic throttle body (ETM) has two distinct revisions (pre/post 2002) requiring correct part number matching (Volvo SIB 11131-2003).
The B6304T4's primary reliability risk is electronic throttle body (ETM) failure, with elevated incidence in high-mileage vehicles. Volvo internal service data indicated a significant failure rate before 150,000 km, while owner surveys frequently cite this as the most common electrical fault. Extended periods of inactivity or voltage fluctuations can accelerate potentiometer wear, making electrical system health critical.
Analysis derived from Volvo technical bulletins (2000-2005) and aggregated European owner association failure statistics (2005-2020). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLVO B-6304-T4.
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