The Volkswagen BAG is a 1,781 cc, inline‑four naturally aspirated petrol engine produced between 2000 and 2008. It features a cast iron block, aluminium head, double overhead camshafts (DOHC), and 20 valves. This unit, part of the EA113 family, delivered 92 kW (125 PS) and 170 Nm of torque, providing smooth, linear power delivery characteristic of its era.
Fitted primarily to the Mk4 Golf, B5 Passat, and SEAT Toledo, the BAG was engineered for dependable daily commuting an…
Volkswagen
Production years 2000–2005 meet Euro 3 standards; 2006–2008 models meet Euro 4 .
The Volkswagen BAG is a 1,781 cc inline‑four naturally aspirated petrol engine engineered for compact and mid-size sedans/hatchbacks (2000-2008). It combines DOHC 20-valve architecture with a variable intake manifold to deliver smooth, linear power and good fuel efficiency. Designed to meet Euro 3 and Euro 4 standards, it offers a blend of reliability and cost-effective motoring.
| Parameter | Value | Source |
|---|---|---|
Displacement | 1,781 cc | |
Fuel type | Petrol | |
Configuration | Inline‑4, DOHC, 20‑valve | |
Aspiration | Naturally aspirated | |
Bore × stroke | 81.0 mm × 86.4 mm | |
Power output | 92 kW (125 PS) @ 5,700 rpm | |
Torque | 170 Nm @ 4,200 rpm | |
Fuel system | Bosch Motronic ME 7.5, multi-point injection | |
Emissions standard | Euro 3 (2000–2005); Euro 4 (2006–2008) | |
Compression ratio | 10.8:1 | |
Cooling system | Water‑cooled | |
Turbocharger | None | |
Timing system | Toothed belt | |
Oil type | Refer to vehicle handbook / manufacturer specification | |
Dry weight | 125 kg |
The Volkswagen BAG was used across Volkswagen's A4 and B5 platforms with transverse mounting. This engine received platform-specific adaptations-reinforced engine mounts in the Passat and a unique air intake duct for the Golf. 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 BAG's primary reliability risk is coolant loss from the failing plastic flange, with elevated incidence in high-mileage vehicles. Volkswagen TSB 2017890 documents this as a widespread service item, while owner reports frequently cite overheating incidents. Neglecting this simple repair can lead to warped cylinder heads or complete engine failure, making proactive replacement critical.
Analysis derived from Volkswagen technical bulletins (2000-2008) and aggregated owner repair data. 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 BAG engine is generally very reliable if its two main weaknesses are addressed: the plastic coolant flange and the timing belt. Proactively replacing the flange with the metal version and adhering to the 90,000 km timing belt interval can result in trouble-free operation beyond 250,000 km. Neglecting either item can lead to expensive repairs.
The most common and critical problems are coolant flange failure and timing belt failure. Secondary issues include ignition coil failures and, in poorly maintained examples, oil sludge buildup. These are well-documented in Volkswagen service bulletins, with the coolant flange being the most frequent and easily preventable failure.
The BAG engine was primarily used in the Mk4 Golf (2000-2006), B5 Passat (2000-2005), and was also found in the SEAT Toledo (2000-2004) and Škoda Octavia (2001-2004). It was the 1.8 20V variant for these specific applications.
Yes, the BAG responds well to tuning. A simple ECU remap can yield gains of 15-25 kW. With supporting modifications like a performance exhaust and intake, outputs of 110-120 kW are achievable. The bottom end is robust, but ensuring the cooling system (especially the flange) is in perfect condition is crucial before any tuning.
Fuel economy is respectable for its time. Expect around 9.5 L/100km (30 mpg UK) in city driving and 6.5 L/100km (43 mpg UK) on the highway for a Golf. The heavier Passat will be slightly thirstier, averaging around 10.0 L/100km (28 mpg UK) combined in mixed driving conditions.
Yes. The BAG is an interference engine. If the timing belt fails, the pistons will collide with the open valves, causing severe and expensive internal damage. This makes adhering to the timing belt replacement schedule non-negotiable for engine survival.
Volkswagen mandates oil meeting the VW 502 00 specification, typically a 5W-40 synthetic. Using the correct oil is important for preventing sludge buildup and protecting engine components. Extended drain intervals or incorrect oil will accelerate wear and can lead to premature failure.
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.