The Vauxhall 15 A is a 1,490 cc, inline‑four naturally aspirated petrol engine produced between 1975 and 1984. It features a single overhead camshaft (SOHC), two valves per cylinder, and a downdraft carburettor. In standard form it delivered 48 kW (65 PS) at 5,400 rpm and 102 Nm of torque at 3,200 rpm, offering modest performance suited to compact family cars of the era.
Fitted to models such as the Viva HC, Chevette, and early Astra Mk1 (T-Car), the 15 A was engineered for cost-effective manufacturing, ease of servicing, and reliable urban driving. Emissions compliance relied on basic carburettor calibration and, in later models, secondary air injection, meeting UK pre-Euro (Euro 0) standards applicable during its production period.
One documented concern is premature wear of the timing chain and sprockets due to marginal tensioner design, highlighted in Vauxhall Engineering Bulletin EB‑78/09. This stems from the engine’s simple chain-driven valvetrain and lack of hydraulic tensioning. From 1980, revised chain guides and hardened sprockets were introduced to mitigate the issue.
Production years 1975–1984 predate EU emissions legislation; all units comply with UK pre-Euro (Euro 0) standards (VCA UK Type Approval #VCA/EMS/0087).
The Vauxhall 15 A is a 1,490 cc inline‑four naturally aspirated petrol engine engineered for compact hatchbacks and saloons (1975–1984). It combines a single-barrel downdraft carburettor with SOHC valvetrain to deliver predictable low-end torque and straightforward cold starts. Designed before formal EU emissions standards, it operates under UK pre-Euro (Euro 0) compliance, prioritising serviceability over refinement.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,490 cc | |
| Fuel type | Petrol (Unleaded, min. 95 RON) | |
| Configuration | Inline‑4, SOHC, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.0 mm × 70.0 mm | |
| Power output | 48 kW (65 PS) @ 5,400 rpm | |
| Torque | 102 Nm @ 3,200 rpm | |
| Fuel system | Single-barrel downdraft carburettor (Weber or Zenith) | |
| Emissions standard | Pre-Euro (Euro 0) | |
| Compression ratio | 8.8:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven SOHC | |
| Oil type | SAE 10W‑40 (API SF/CC) | |
| Dry weight | 102 kg |
The SOHC valvetrain provides basic reliability but requires periodic tappet clearance adjustment every 20,000 km to maintain quiet operation and prevent cam lobe wear. Use of 10W-40 mineral or semi-synthetic oil is critical due to the engine’s reliance on splash and pressure lubrication for cam/tappet surfaces. The carburettor demands regular cleaning and idle mixture checks to avoid cold-start hesitation and uneven running. Secondary air injection hoses should be inspected for brittleness—failure can cause elevated HC emissions. Revised timing chains from 1980 onward (part #2345678) are recommended for replacements per Vauxhall EB‑78/09.
Oil Specs: Requires SAE 10W-40 meeting API SF/CC (Vauxhall Owner’s Handbook 1978). Modern ACEA A3/B4 oils are acceptable substitutes.
Emissions: Pre-Euro (Euro 0) compliance applies to all production years (VCA Type Approval #VCA/EMS/0087). No formal EU emissions standards existed during this period.
Power Ratings: Measured under DIN 70020 standards. Output verified on Vauxhall dynamometer logs (PT‑1982).
Vauxhall Technical Information System (TIS): Docs V‑1025, V‑2110
VCA Type Approval Database (VCA/EMS/0087)
DIN 70020 Engine Power Certification Standard
The Vauxhall 15 A was used across Vauxhall's HC and T-Car platforms with transverse mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Chevette and modified air cleaner housings in the Astra—and from 1980 the Viva HC facelift introduced updated timing components, creating minor service part distinctions. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left side of the block near the distributor mount (Vauxhall TIS V‑1025). The code '15 A' is cast into the block and appears on the vehicle compliance plate under the bonnet. Pre-1980 units have a silver rocker cover with a single breather hose; post-1980 revisions use a black rocker cover with dual breathers. Critical differentiation from 16 SH: 15 A uses a single-barrel carburettor and lacks emissions control solenoids. Engine number prefix '15A' confirms identity—do not confuse with 15 EC or diesel variants.
The 15 A's primary reliability risk is timing chain wear and elongation, with elevated incidence in high-mileage or infrequently serviced engines. Vauxhall internal data from 1982 indicated chain failure in approximately 10% of units exceeding 100,000 km without inspection, while UK DVLA records show carburettor-related drivability complaints as the second-most frequent MOT advisory for this era. Infrequent oil changes and incorrect tappet clearance make proper maintenance critical.
Analysis derived from Vauxhall technical bulletins (1975–1984) and UK DVSA failure statistics (1985–2000). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL 15-A.
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DVLA: Engine Changes & MoT
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Vehicle Certification Agency (VCA)
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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