The Volkswagen GN is a 1,584 cc, air‑cooled flat‑four petrol engine produced between 1974 and 1983. It featured an overhead valve (OHV) layout with a single downdraft carburettor and delivered 44–50 kW (60–68 PS), depending on market and compression ratio. Its robust magnesium crankcase and simplified valvetrain provided dependable performance for utility and light commercial applications.
Fitted primarily to the Volkswagen Type 2 (T2b/T3) Bus and the Type 181 “Kurierwagen” (Thing), the GN was engineered for durability in varied climates and driving conditions. Emissions compliance relied on mechanical carburetion and exhaust tuning under pre‑Euro German national standards governed by KBA type approvals.
One documented concern is cylinder head stud thread wear in the magnesium crankcase, particularly in high‑mileage or overheated engines. This issue, referenced in Volkswagen Service Bulletin T2‑73‑08, stems from thermal cycling and dissimilar metal expansion between steel studs and the magnesium case. Later production batches introduced case reinforcement and revised torque procedures to mitigate cracking.
Production years 1974–1983 predate formal Euro emissions standards; compliance was governed by national regulations (KBA Type Approval #50A/74).
The Volkswagen GN is a 1,584 cc air‑cooled flat‑four petrol engine engineered for light commercial and utility vehicles (1974–1983). It combines a single carburettor induction system with OHV valvetrain to deliver smooth low‑rpm torque and mechanical simplicity. Designed before Euro emissions frameworks, it adheres to 1970s German national standards under KBA oversight.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,584 cc | |
| Fuel type | Petrol (Unleaded or leaded, depending on market) | |
| Configuration | Flat‑4, OHV, 8‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 93.0 mm × 58.0 mm | |
| Power output | 44–50 kW (60–68 PS) @ 4,200–4,500 rpm | |
| Torque | 118–128 Nm @ 2,400–2,800 rpm | |
| Fuel system | Single downdraft carburettor (Solex 34 PICT‑3) | |
| Emissions standard | Pre‑Euro (German national standards) | |
| Compression ratio | 7.3:1 – 7.7:1 (market‑dependent) | |
| Cooling system | Air‑cooled (fan‑driven) | |
| Turbocharger | None | |
| Timing system | Gear‑driven camshaft | |
| Oil type | SAE 20W‑50 mineral oil (API SF/CC) | |
| Dry weight | 102 kg |
The GN engine’s air‑cooled design offers mechanical simplicity but demands vigilant thermal management—especially in stop‑start traffic or hot climates—to avoid overheating and case distortion. Regular valve clearance checks (every 5,000 km) are essential due to the solid lifter OHV system. Use of correct SAE 20W‑50 oil ensures adequate film strength under high case temperatures. Cylinder head stud integrity should be inspected during major services; engines with known overheating history may require case thread repair per Volkswagen T2‑73‑08. Fuel must meet minimum 91 RON (pre‑unleaded era specs); ethanol blends above 5% risk carburettor seal degradation.
Oil Specs: Requires SAE 20W‑50 mineral oil meeting API SF/CC (Volkswagen Service Bulletin T2‑73‑08). Synthetic oils not recommended for original seals.
Emissions: Pre‑Euro emissions governed by German national law (KBA Type Approval #50A/74). No Euro classification applies.
Power Ratings: Measured under DIN 70020 standards. Output varies by compression ratio and carburettor jetting per market (KBA #50A/74).
Volkswagen Technical Information System (TIS): Workshop Manual 1975, ETK 1978
Kraftfahrt-Bundesamt (KBA) Type Approval Database (#50A/74)
Volkswagen Service Bulletin T2‑73‑08
DIN 70020 Engine Power Measurement Standard
The Volkswagen GN was used across Volkswagen's Type 2 (T2b/T3) and Type 181 platforms with rear‑mounted longitudinal orientation and no external licensing. This engine received platform-specific adaptations—reinforced engine mounts in the Bus and modified cooling shrouds in the Thing—and from 1975 the T2b update introduced revised carburettor jetting for emissions, 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 Workshop Manual 1975, Fig. 01‑1/3). The GN code appears as a raised cast mark followed by the serial number. Visual identification: single carburettor, air‑cooled fan housing, and 8‑fin cylinder heads distinguish it from earlier 1500/1300 units. Critical differentiation from FA/FR/GD engines: GN shares identical displacement but typically features updated carburettor jetting and minor case revisions. Engine number prefix 'GN' confirms identity; mismatched codes may indicate replacement with non‑OEM unit.
The GN's primary reliability risk is magnesium crankcase thread wear around cylinder head studs, with elevated incidence in high‑mileage or overheated engines. Volkswagen internal service data from 1976 noted a significant share of T2 engines requiring case repair or replacement after 150,000 km, while KBA field reports linked repeated overheating to case distortion. Thermal stress from inadequate airflow or incorrect ignition timing makes proper cooling and maintenance critical.
Analysis derived from Volkswagen technical bulletins (1974–1983) and KBA failure statistics (1975–1985). Repair procedures should follow manufacturer guidelines.
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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