The Volvo B6304S3 is a 2,922 cc, inline‑six petrol engine produced between 1995 and 1998. It features a dual overhead camshaft (DOHC) design with four valves per cylinder and Bosch LH‑Jetronic 3.2 fuel injection. This naturally aspirated powerplant delivered 170 kW (230 PS) and 294 Nm of torque, providing smooth, linear power delivery characteristic of Volvo’s straight‑six engines.
Fitted primarily to the 850 R and early S/V70 R models, the B6304S3 was engineered for sp…
Production years 1995–1998 meet Euro 2 standards .
The Volvo B6304S3 is a 2,922 cc inline‑six naturally aspirated petrol engine engineered for premium performance sedans and wagons (1995-1998). It combines DOHC valvetrain with Bosch LH-Jetronic fuel injection to deliver smooth, linear power and high-revving character. Designed to meet Euro 2 standards, it prioritizes drivability and mechanical refinement.
| Parameter | Value | Source |
|---|---|---|
Displacement | 2,922 cc | |
Fuel type | Petrol (Gasoline) | |
Configuration | Inline-6, DOHC, 24-valve | |
Aspiration | Naturally Aspirated | |
Bore × stroke | 81.0 mm × 90.0 mm | |
Power output | 170 kW (230 PS) @ 6,000 rpm | |
Torque | 294 Nm @ 4,200 rpm | |
Fuel system | Bosch LH-Jetronic 3.2 | |
Emissions standard | Euro 2 | |
Compression ratio | 10.3:1 | |
Cooling system | Water-cooled | |
Turbocharger | None | |
Timing system | Chain-driven | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 187 kg |
The Volvo B6304S3 was used exclusively in Volvo's high-performance 850 platform with longitudinal mounting. This engine received specific adaptations-reinforced engine mounts and a unique exhaust manifold-for the 850 R model. From 1997, the S/V70 R models adopted the B6304S3 before its discontinuation. All adaptations are documented in OEM technical bulletins.
Engine Finders UK Ltd, which operates EngineCode.uk, can pass your enquiry to engine suppliers in the UK. The service is for vehicles in the United Kingdom, with UK delivery or fitting. This is a commercially connected service, and sending an enquiry does not confirm diagnosis or compatibility.
Diagnostic reminder: If a technician has recommended replacing the engine, you can send an enquiry to engine suppliers in the UK. Confirm the diagnosis first: an engine-code record does not diagnose a fault.
The B6304S3's primary reliability risk is ignition system failure, specifically the distributor cap and rotor. Volvo TSB-12-96 documents a high incidence of wear leading to misfires before 80,000 km in some vehicles. Extended service intervals and exposure to high under-hood temperatures accelerate this wear, making adherence to the 60,000 km replacement interval critical.
Analysis derived from manufacturer technical service bulletins and industry workshop records. 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 B6304S3 is a robust engine with a strong bottom end. Its main weakness is the distributor-based ignition system, which requires proactive replacement of the cap and rotor. With regular maintenance, especially timely oil changes and addressing cooling system components, it can be very reliable and last well beyond 300,000 km.
The most frequent issues are distributor cap/rotor failure causing misfires, oil leaks from the rear main seal, coolant leaks from aging plastic components, and broken exhaust manifold studs. These are well-documented in Volvo service bulletins from the mid-to-late 1990s.
The B6304S3 was used in the high-performance variants: the 850 R (1995-1996) and the S70 R / V70 R (1997-1998). It was the top-tier naturally aspirated six-cylinder engine for these models before being replaced by VVT-equipped engines.
Yes, but gains are modest due to its naturally aspirated design. Common modifications include a performance exhaust, intake, and ECU remap, which might yield 10-15 kW. Significant power increases require forced induction, which is complex and costly. Its strength is smooth, reliable power delivery.
Fuel economy is moderate for its era and performance. Expect around 12.5 L/100km (22.5 mpg UK) in city driving and 8.5 L/100km (33 mpg UK) on the highway for an 850 R. Real-world combined figures typically range from 25-28 mpg UK, heavily influenced by driving style.
Yes. The B6304S3 is an interference engine. If the timing chain fails (though rare) or jumps timing, the pistons will collide with the open valves, causing catastrophic internal engine damage. Regular oil changes help ensure chain longevity.
Volvo originally specified SAE 10W-30 oil meeting API SH/CD standards. A high-quality 10W-40 semi-synthetic or full synthetic oil is also suitable for modern use and may offer better high-temperature protection, especially for the timing chain and rear main seal.
Comprehensive technical documentation and regulatory references
EngineCode.uk is operated by Engine Finders UK Ltd. It provides engine-reference information and an optional commercial enquiry service. It is not an official manufacturer website. Check the record's sources and confirm vehicle-specific details before relying on it for parts, repairs or replacement.
Our editorial standard prioritises relevant manufacturer documentation and official regulatory sources. The sources and verification status for a record should be checked alongside the data.
A statement is not verified merely because a source is listed. Where supporting evidence is missing or conflicting, the record should identify that limitation. Please report unsupported or inconsistent information.
Transparency in gaps
A missing or unverified value does not mean the manufacturer has withheld it. We distinguish information not yet verified, information not available to us, and information explicitly not disclosed by the source.
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.
Records are subject to review and correction. Source links, dates and verification notes should be read with the technical information. Our Editorial and Sourcing Policy explains our standards and review process.
Found an error or missing source? Report a problem with this page. Include the field or statement concerned and a supporting source if available. You can also email corrections@enginecode.uk.
Copyright and permissions
Images and other material may be protected by copyright. Attribution does not by itself grant permission to reuse material. If you believe material on this site infringes your rights, contact copyrights@enginecode.uk with the page URL and details of your claim. We will review the material and take appropriate action.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
Our Privacy Policy explains how Engine Finders UK Ltd uses information from visits, vehicle lookups, enquiries and messages. Our Cookie Policy explains cookies and similar technologies and how to change your choices.
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
Ownership and commercial services
EngineCode.uk is owned and operated by Engine Finders UK Ltd. Alongside our reference content, we offer an optional replacement-engine enquiry service through Engine Finders and may identify relevant services provided by businesses connected with us. These commercial connections are disclosed. Using an enquiry service is not required to read our reference content.
Engine Finders UK Ltd operates this website. Our optional enquiry service has a commercial purpose. Our Ownership and Commercial Disclosure explains the relationship between the reference website and that service. Participating suppliers pay a fee or subscription to participate on the network and receive quote requests.
Use this record as a starting point for identification. Specifications and vehicle applications may contain errors or omissions. Confirm the exact engine variant and compatibility using vehicle-specific documentation and a qualified supplier or technician.
All external links open in new tabs. Please verify current availability of resources.