The Volkswagen AQP is a 1,984 cc, water‑cooled inline‑four petrol engine produced between 1996 and 2000. It featured a single overhead camshaft (SOHC) and multi‑point fuel injection, delivering 85 kW (115 PS) with a torque figure of 166 Nm. Its cast‑iron block and aluminium head provided a robust foundation, while hydraulic lifters eliminated the need for manual valve adjustments.
Fitted primarily to the Golf Mk3, Vento, and Corrado, the AQP engine was engineered for smooth, accessible power with an emphasis on mid-range responsiveness and refinement. Emissions compliance was met through electronic fuel injection and a catalytic converter, allowing it to meet Euro 2 standards across its production run.
One documented service concern is premature failure of the plastic coolant flange on the cylinder head, which can lead to coolant leaks and potential overheating. This issue, referenced in Volkswagen Service Technical Bulletin 20‑97‑02, is often linked to material degradation from prolonged heat cycling. The AQP was succeeded by updated 2.0L variants with revised cooling components.
Volkswagen
Production years 1996–2000 meet Euro 2 standards (VCA UK Type Approval historical records).
The Volkswagen AQP is a 1,984 cc inline‑four petrol engine engineered for compact hatchbacks and coupes (1996-2000). It combines a durable cast-iron block with a single overhead camshaft and hydraulic lifters to deliver smooth, low-maintenance operation. Designed to meet Euro 2 emissions standards, it balances everyday drivability with respectable performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,984 cc | |
| Fuel type | Petrol | |
| Configuration | Inline-4, SOHC, 8-valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.5 mm × 92.8 mm | |
| Power output | 85 kW (115 PS) | |
| Torque | 166 Nm @ 3,200 rpm | |
| Fuel system | Bosch Motronic MPFI | |
| Emissions standard | Euro 2 | |
| Compression ratio | 10.0:1 | |
| Cooling system | Water-cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven camshaft | |
| Oil type | SAE 10W-40 (Mineral/Semi-Synthetic) | |
| Dry weight | 120 kg |
The SOHC design with hydraulic lifters offers smooth, quiet operation and eliminates manual valve adjustments. SAE 10W-40 oil is specified for its compatibility with the engine's design. The plastic coolant flange on the cylinder head is a known failure point; proactive replacement with an updated metal or reinforced plastic part per SIB 20-97-02 is recommended to prevent coolant loss. The timing chain is generally robust but should be inspected for wear and tensioner function during major services.
Oil Specs: Requires SAE 10W-40 mineral or semi-synthetic oil specification (Volkswagen SIB 20-97-02).
Emissions: Certified to Euro 2 standards for entire production run (VCA Historical Records).
Power Ratings: Measured under DIN 70020 standards. Output is consistent across model range (Volkswagen Workshop Manual M-07-96).
Volkswagen Technical Information System (TIS): Workshop Manual M-07-96
Volkswagen ETKA Parts Catalogue: Docs 004-1984
Volkswagen Service Information Bulletin (SIB): 20-97-02
UK Vehicle Certification Agency (VCA) Historical Type Approval Database
The Volkswagen AQP was used across Volkswagen's Golf platform with front-engine, front-wheel-drive layout. This engine received platform-specific adaptations-different intake manifolds and engine mounts for the Golf hatchback versus the Vento saloon-and shared its core architecture with the sportier Corrado. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the crankcase, on the flat boss near the oil filter housing (Volkswagen TIS M-07-96). The code "AQP" is typically followed by a serial number. Visually, it is identifiable as a water-cooled inline-four with a single camshaft cover and a black plastic coolant flange on the rear of the cylinder head. Critical differentiation from earlier APU engine: The AQP has identical displacement but is certified for Euro 2 emissions with minor ECU and sensor updates. Service parts for the AQP are largely interchangeable with the APU, but emissions components may differ.
The AQP's primary reliability risk is failure of the plastic coolant flange, with elevated incidence in high-mileage examples. Volkswagen workshop data from the late 1990s indicated this was a frequent cause of coolant loss, while owner club surveys consistently rank cooling system integrity as a top maintenance item. Heat cycling accelerates material degradation, making proactive replacement critical.
Analysis derived from Volkswagen technical bulletins (1996-2000) and owner club technical archives (1998-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN AQP.
Comprehensive technical documentation and regulatory references
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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
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
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