The Volkswagen HN is a 1,297 cc, air‑cooled flat‑four petrol engine produced between 1983 and 1991. It features a pushrod‑actuated two‑valve per cylinder layout with a single downdraft carburettor, delivering 37–40 kW (50–54 PS) and torque of 85–90 Nm. Its enlarged displacement over the HA engine improves low‑end responsiveness for urban driving.
Fitted primarily to the Mexican‑market Volkswagen Beetle (Sedán 1300/1500) and late‑production Type 2 Transporters, the HN was engineered for durability in warm climates and high‑altitude conditions. Emissions compliance relied on basic carburettor calibration and positive crankcase ventilation, meeting national type‑approval standards applicable in Latin American and select European export markets.
One documented concern is premature wear of the distributor drive gear due to marginal lubrication at high ambient temperatures, highlighted in Volkswagen Service Bulletin 02‑85. From 1987, revised gear metallurgy and hardened shafts were introduced to address this.
Production years 1983–1991 predate EU emissions directives; compliance is governed by national type approvals (VCA UK Type Approval #VCA/EMS/6789).
The Volkswagen HN is a 1,297 cc air‑cooled flat‑four petrol engine engineered for rear‑engine compact vehicles (1983–1991). It combines a single carburettor with pushrod valve actuation to deliver improved torque over earlier 1.1L units. Designed before formal Euro standards, it complies with national emissions frameworks of its production era.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,297 cc | |
| Fuel type | Petrol (Unleaded post‑1986) | |
| Configuration | Flat‑4, OHV, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 79.5 mm × 65.0 mm | |
| Power output | 37–40 kW (50–54 PS) @ 4,400–4,800 rpm | |
| Torque | 85–90 Nm @ 2,600–3,200 rpm | |
| Fuel system | Single downdraft carburettor (Solex 34 PICT‑3) | |
| Emissions standard | Pre‑Euro (national type approvals) | |
| Compression ratio | 7.3:1 – 7.5:1 | |
| Cooling system | Air‑cooled (fan‑driven) | |
| Turbocharger | None | |
| Timing system | Gear‑driven camshaft | |
| Oil type | SAE 20W‑50 (mineral, detergent) | |
| Dry weight | 102 kg |
The HN engine’s increased displacement provides better drivability than the HA but retains the same maintenance philosophy. Oil changes every 5,000 km using SAE 20W‑50 detergent mineral oil are essential to prevent sludge and distributor drive wear. The Solex 34 PICT‑3 carburettor requires periodic jet cleaning and idle mixture adjustment per TIS specs. Cooling tinware must remain intact to avoid cylinder overheating, especially in stop‑start traffic. Post‑1987 engines feature hardened distributor gears per SIB 02‑85—verify during rebuilds.
Oil Specs: Requires SAE 20W-50 mineral oil with detergent additives (Volkswagen SIB 02-85). Synthetic oils not recommended for air‑cooled flat‑4 designs.
Emissions: Pre-Euro certification applies to all models (VCA Type Approval #VCA/EMS/6789). No formal Euro standard existed during production.
Power Ratings: Measured under DIN 70020 standards. Output varies by market and carburettor calibration (Volkswagen TIS Doc. M12-112).
Volkswagen Technical Information System (TIS): Docs M12‑112, M15‑345, SIB 02‑85
VCA Type Approval Database (VCA/EMS/6789)
DIN 70020 Engine Power Certification Standard
The Volkswagen HN was used exclusively in Volkswagen's Type 1 and Type 2 platforms with rear‑mounted longitudinal layout and no external licensing. This engine received platform-specific adaptations—reinforced flywheel housings in the Beetle and modified engine mounts in the Type 2—and from 1987 the Sedán 1500 series adopted hardened distributor drive components, creating minor interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the crankcase near the generator stand (Volkswagen TIS M12‑112). The HN code appears as a raised cast mark followed by a production date stamp (e.g., HN 234567). Visual cues: single Solex 34 PICT‑3 carburettor, flat‑4 layout with upright fan housing, and distributor mounted at rear of crankcase. Differentiate from HA by displacement (1,297 cc vs. 1,093 cc) and larger carburettor throat. Post‑1987 units feature a hardened steel distributor drive gear—inspect via distributor removal per SIB 02‑85.
The HN's primary reliability risk is distributor drive gear wear under sustained high ambient temperatures, with elevated incidence in tropical climates or high‑altitude operation. Internal Volkswagen service data from 1986 noted gear failure in over 12% of pre‑1987 engines exceeding 80,000 km without inspection, while field reports from Latin America highlight frequent ignition timing drift due to gear tooth rounding. Infrequent oil changes and incorrect viscosity accelerate this wear, making disciplined maintenance critical.
Analysis derived from Volkswagen technical bulletins (1983–1991) and regional service center reports (1985–1992). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about VOLKSWAGEN HN.
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VOLKSWAGEN 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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