The Vauxhall 15LN is a 1,488 cc, inline‑four naturally aspirated petrol engine produced between 1979 and 1987. It features a cast‑iron block, aluminium cylinder head, overhead valve (OHV) layout, and a single downdraft carburettor. In standard form it delivered 48–52 kW (65–71 PS) with torque of 102–108 Nm, providing modest performance suitable for compact city driving.
Fitted to models such as the Vauxhall Astra Mk1 (T-Car), Chevette, and early Nova, the 15LN was engineered for economical urban commuting and light-duty use. Emissions compliance was achieved through basic positive crankcase ventilation and lean‑burn carburettor tuning, meeting UK and EU Type Approval requirements under pre‑Euro standards (VCA Type Approval #VCA/EMS/5678).
One documented concern is premature wear of the distributor drive gear, which can cause timing drift and misfires. This issue, highlighted in Vauxhall Service Bulletin SB‑79/12, is attributed to insufficient surface hardening on early production gears. From 1983 onward, revised components with improved metallurgy were introduced to address the problem.
Production years 1979–1987 predate formal Euro emissions standards; all units comply with UK Type Approval requirements in force at time of manufacture (VCA UK Type Approval #VCA/EMS/5678).
The Vauxhall 15LN is a 1,488 cc inline‑four OHV petrol engine engineered for compact hatchbacks and saloons (1979–1987). It combines a single-barrel carburettor with a durable cast-iron architecture to deliver reliable low-cost motoring. Designed to meet pre-Euro UK emissions regulations, it prioritises simplicity and serviceability over performance.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,488 cc | |
| Fuel type | Petrol (Unleaded or Lead Replacement) | |
| Configuration | Inline‑4, OHV, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 82.5 mm × 69.8 mm | |
| Power output | 48–52 kW (65–71 PS) @ 5,200–5,600 rpm | |
| Torque | 102–108 Nm @ 3,000–3,400 rpm | |
| Fuel system | Single-barrel downdraft carburettor (Zenith/Stromberg) | |
| Emissions standard | Pre-Euro (UK Type Approval compliant) | |
| Compression ratio | 8.8:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Gear-driven camshaft (front-mounted) | |
| Oil type | SAE 10W‑40 (API SF/CC or equivalent) | |
| Dry weight | 125 kg |
The OHV layout offers mechanical simplicity and ease of maintenance but delivers modest performance by modern standards. Regular valve clearance checks (every 20,000 km) are essential due to mechanical tappet design. Use of lead-replacement petrol or additive is recommended for pre-1986 units to protect valve seats. The distributor drive gear requires inspection if timing instability or misfire occurs—early units (pre-1983) should be upgraded per Vauxhall SB‑79/12. Carburettor jets may require recalibration in high-altitude or cold climates to maintain stoichiometry.
Oil Specs: Requires SAE 10W-40 meeting API SF/CC (Vauxhall Owner Handbook 1983). Modern ACEA A3/B4 oils are acceptable substitutes.
Emissions: Pre-Euro certification applies to all 1979–1987 models (VCA Type Approval #VCA/EMS/5678). No formal Euro standard existed during production.
Power Ratings: Measured under DIN 70020 standards. Output varies by model year and carburettor calibration (Vauxhall PT‑1985).
Vauxhall Technical Information System (TIS): Docs M78‑112, V15‑3342
VCA Type Approval Database (VCA/EMS/5678)
Vauxhall Service Bulletin SB‑79/12
The Vauxhall 15LN was used across Vauxhall's T-Car and Chevette platforms with longitudinal mounting and no external licensing. This engine received platform-specific adaptations—revised engine mounts in the Chevette and modified air cleaner assemblies in the Astra—and from 1984 the Nova adopted a compact sump variant, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the left-hand side of the block near the distributor (Vauxhall TIS M78‑112). The code '15LN' appears as a raised cast mark followed by a production date stamp (e.g., '83L' for October 1983). Pre-1983 units have a silver distributor housing and cast-iron inlet manifold; post-1983 units use black plastic air cleaner housings and revised distributor gears. Critical differentiation from 13N: 15LN has larger bore (82.5 mm vs. 78.0 mm) and distinct carburettor linkage. Service parts for timing gears require verification against SB‑79/12—pre-1983 gears are not interchangeable with later hardened versions.
The 15LN's primary reliability risk is distributor drive gear wear on early builds, with elevated incidence in high-mileage or hot-climate use. Vauxhall internal data from 1982 noted premature gear failure in ~15% of pre-1983 engines before 100,000 km, while UK DVSA records show carburettor-related emissions faults as common in MOT failures for this era. Extended service intervals and incorrect fuel accelerate wear, making valve clearance checks and fuel quality critical.
Analysis derived from Vauxhall technical bulletins (1979–1987) and UK DVSA failure statistics (1990–2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VAUXHALL 15LN.
Comprehensive technical documentation and regulatory references
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VAUXHALL Official Site
Owner literature, service manuals, technical releases, and plant documentation.
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.
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