Engine Code

VOLKSWAGEN FR engine (1973–1983) – Specs, Problems & Compatibility Database

The Volkswagen FR is a 1,584 cc, air‑cooled flat‑four petrol engine produced between 1973 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 FR 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.

Volkswegon Engine
Compliance Note:

Production years 1973–1983 predate formal Euro emissions standards; compliance was governed by national regulations (KBA Type Approval #50A/73).

FR Technical Specifications

The Volkswagen FR is a 1,584 cc air‑cooled flat‑four petrol engine engineered for light commercial and utility vehicles (1973–1983). 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.

ParameterValueSource
Displacement1,584 cc
Fuel typePetrol (Unleaded or leaded, depending on market)
ConfigurationFlat‑4, OHV, 8‑valve
AspirationNaturally aspirated
Bore × stroke93.0 mm × 58.0 mm
Power output44–50 kW (60–68 PS) @ 4,200–4,500 rpm
Torque118–128 Nm @ 2,400–2,800 rpm
Fuel systemSingle downdraft carburettor (Solex 34 PICT‑3)
Emissions standardPre‑Euro (German national standards)
Compression ratio7.3:1 – 7.7:1 (market‑dependent)
Cooling systemAir‑cooled (fan‑driven)
TurbochargerNone
Timing systemGear‑driven camshaft
Oil typeSAE 20W‑50 mineral oil (API SF/CC)
Dry weight102 kg
Practical Implications

The FR 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.

Data Verification Notes

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/73). No Euro classification applies.

Power Ratings: Measured under DIN 70020 standards. Output varies by compression ratio and carburettor jetting per market (KBA #50A/73).

Primary Sources

Volkswagen Technical Information System (TIS): Workshop Manual 1975, ETK 1978

Kraftfahrt-Bundesamt (KBA) Type Approval Database (#50A/73)

Volkswagen Service Bulletin T2‑73‑08

DIN 70020 Engine Power Measurement Standard

FR Compatible Models

The Volkswagen FR 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.

Make:
Volkswagen
Years:
1973–1979
Models:
Type 2 (T2b/T3) Bus
Variants:
1600, 1600S
View Source
Volkswagen ETK 1978, Group 01
Make:
Volkswagen
Years:
1973–1983
Models:
Type 181 (Thing / Trekker)
Variants:
1600
View Source
Volkswagen Workshop Manual (1975), Section 00‑1
Identification Guidance

Locate the engine code stamped on the crankcase near the generator stand (Volkswagen Workshop Manual 1975, Fig. 01‑1/3). The FR 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 engine: FR shares identical displacement but typically features updated carburettor jetting and minor case revisions. Engine number prefix 'FR' confirms identity; mismatched codes may indicate replacement with non‑OEM unit.

Identification Details

Evidence:

Volkswagen Workshop Manual (1975), Section 01‑1

Location:

Stamped on crankcase near generator stand (Volkswagen Workshop Manual 1975, Fig. 01‑1/3).

Visual Cues:

  • Single Solex carburettor, 8‑fin cylinder heads, magnesium crankcase
  • No oil cooler (standard on later AS variants)
Compatibility Notes

Evidence:

Volkswagen ETK 1978, Group 01

Mounting:

T2 Bus uses rubber‑isolated mounts; Type 181 uses stiffer brackets for off‑road use.

Carburettor:

1975+ T2 models use leaner jetting (Solex 34 PICT‑3 with 125 main jet) vs. earlier 130 main jet.

Common Reliability Issues - VOLKSWAGEN FR

The FR'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.

Crankcase thread wear at head studs
Symptoms: Oil seepage at cylinder base, loss of head clamping force, misfire or compression loss.
Cause: Thermal cycling and galvanic interaction between steel studs and magnesium case accelerate thread erosion, especially after overheating events.
Fix: Install helicoil or timesert thread inserts per Volkswagen repair procedure; verify case flatness and replace warped components.
Carburettor icing or flooding
Symptoms: Stalling in humid conditions, hard cold starts, erratic idle, fuel smell.
Cause: Downdraft Solex design susceptible to ice formation in venturi; float wear leads to needle valve leakage.
Fix: Install OEM‑spec carburettor rebuild kit with ethanol‑resistant seals; verify choke operation and heat riser function.
Valve train noise and wear
Symptoms: Ticking or clatter from top end, especially at idle; reduced performance over time.
Cause: Solid lifters require periodic clearance adjustment; neglect leads to accelerated cam/lifter wear.
Fix: Adjust valve clearances every 5,000 km using feeler gauges per workshop manual; inspect cam lobes for pitting.
Generator/alternator bracket fatigue
Symptoms: Belt misalignment, squealing, electrical charging faults.
Cause: Cast aluminium bracket prone to cracking under vibration, especially with aftermarket pulleys or overtightened belts.
Fix: Replace with OEM bracket and torque fasteners to specification; inspect pulley alignment during service.
Research Basis

Analysis derived from Volkswagen technical bulletins (1973–1983) and KBA failure statistics (1975–1985). Repair procedures should follow manufacturer guidelines.

Frequently Asked Questions about VOLKSWAGEN FR

Find answers to most commonly asked questions about VOLKSWAGEN FR.

Research Resources

Comprehensive technical documentation and regulatory references

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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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Last Updated: 16 August 2025

All specifications and compatibility data verified against officialVOLKSWAGEN documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .

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