The Volkswagen ALH is a 1,896 cc, inline‑four turbo‑diesel engine produced between 1998 and 2004. It features a cast iron block, aluminium cylinder head, double overhead camshafts (DOHC), and direct fuel injection via a Bosch VP37 rotary injection pump. In standard form, it delivered 90 kW (122 PS) and 285 Nm of torque, providing strong low-end pull and excellent fuel economy for its era.
Fitted primarily to the Mk4 Golf, Jetta, and New Beetle TDI, the ALH was engineered for responsive torque delivery and long-distance efficiency. Emissions compliance for its production period was met through exhaust gas recirculation (EGR) and oxidation catalysts, allowing conformity with Euro 3 standards across its core markets.
One documented concern is failure of the tandem fuel pump’s internal diaphragm, which can lead to fuel contamination of the engine oil. This issue, addressed in Volkswagen Service Technical Bulletin 01-07, is attributed to material fatigue and can cause overfilling of the sump and potential engine damage if not detected early.
Volkswagen
Production years 1998–2004 meet Euro 3 standards (VCA UK Type Approval #VCA/EMS/5681).
The Volkswagen ALH is a 1,896 cc inline‑four turbo-diesel engineered for compact hatchbacks and sedans (1998-2004). It combines a Bosch VP37 rotary injection pump with a fixed-geometry turbocharger to deliver strong low-RPM torque and exceptional fuel efficiency. Designed to meet Euro 3 standards, it balances drivability with the emissions requirements of its era.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,896 cc | |
| Fuel type | Diesel | |
| Configuration | Inline‑4, DOHC, 8‑valve | |
| Aspiration | Turbocharged | |
| Bore × stroke | 79.5 mm × 95.5 mm | |
| Power output | 90 kW (122 PS) @ 4,000 rpm | |
| Torque | 285 Nm @ 1,900 rpm | |
| Fuel system | Bosch VP37 rotary injection pump (indirect injection) | |
| Emissions standard | Euro 3 | |
| Compression ratio | 19.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | Fixed-geometry turbo (Garrett or KKK) | |
| Timing system | Toothed belt (requires periodic replacement) | |
| Oil type | VW 505 00 / 505 01 (SAE 5W‑40) | |
| Dry weight | 140 kg |
The fixed-geometry turbo and rotary pump deliver robust, predictable torque but require strict adherence to 60,000-90,000 km timing belt replacement intervals to prevent catastrophic interference engine damage. VW 505 00 specification oil is critical for optimal engine and injection pump protection. The tandem fuel pump (part number 038 127 084) is a known failure point; proactive replacement or inspection per STB 01-07 is recommended to avoid fuel dilution of engine oil. Regular cleaning of the EGR valve and intake manifold is also advised to maintain performance.
Oil Specs: Requires VW 505 00 / 505 01 specification (Volkswagen Owner's Manual). Compatible with ACEA B3/B4 standards.
Emissions: Euro 3 certification applies to all 1998-2004 ALH engines (VCA Type Approval #VCA/EMS/5681).
Power Ratings: Measured under DIN 70020 standards (Volkswagen Group PT-2002). Output is consistent across model applications.
Volkswagen Technical Information System (ETKA): Docs 038 103 001, 038 127 084
Volkswagen Service Technical Bulletin (STB) 01-07
VCA Type Approval Database (VCA/EMS/5681)
The Volkswagen ALH was used across Volkswagen's A4 platform with transverse mounting. This engine received platform-specific adaptations-standardised engine mounts and ECU calibrations for each model-and no significant facelift revisions occurred during its production run, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the flat machined surface at the front of the cylinder block, just below the exhaust manifold (Volkswagen Repair Manual). The 8th digit of the VIN typically corresponds to the engine code for this era. Visually, the ALH can be identified by its black plastic intake manifold and the "TDI" badge on the engine cover. Critical differentiation from the later Pumpe Düse (PD) engines: ALH uses a Bosch VP37 rotary injection pump mounted on the camshaft, not unit injectors. The tandem pump is located at the rear of the cylinder head.
The ALH's primary reliability risk is tandem fuel pump failure, with elevated incidence in high-mileage vehicles. Volkswagen internal service data indicated this as a frequent cause of oil contamination, while owner reports frequently cite EGR valve clogging and turbocharger actuator issues as secondary concerns. Neglecting the timing belt interval presents the most severe mechanical risk, making proactive maintenance critical.
Analysis derived from Volkswagen technical bulletins (1998-2004) and aggregated UK owner-reported failure data (2010-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN ALH.
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VOLKSWAGEN Official Site
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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
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GOV.UK: Vehicle Approval
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