MAHLE Original Ø 127 mm Clockwise Alternator Cooling Fan - Part Number: 37915900156
The MAHLE Original alternator cooling fan (flywheel) (part number 37915900156, OEM references MGX757, MGX 757, 133874) is an OEM-grade stamped steel airflow impeller engineered to maintain forced convective cooling on heavy-duty alternators fitted to agricultural tractors, combines, and industrial machinery. Specifically calibrated for clockwise (↻ / CW) rotating alternators, it features an outer diameter (Dimension B) of 127 mm, a center shaft mounting bore (Dimension A) of 17 mm, and an overall height/depth (Dimension C) of 14 mm. The precision blade contour ensures high-velocity air circulation through the alternator core, dissipating heat from stator windings, rotor coils, and diode rectifiers under heavy electrical loads.
Key Features & Engineering Advantages
- OEM MAHLE / Letrika Manufacturing Quality: Fabricated to tight original equipment tolerances, preventing radial runout, shaft vibration, and harmonic imbalance at high engine speeds.
- Aerodynamically Optimized for Clockwise Rotation (↻): Vane pitch and curvature draw forced air through the alternator housing to effectively cool internal diode bridges and rotor slip rings.
- High-Strength Heavy-Gauge Steel: Formed from corrosion-treated sheet steel designed to resist fatigue deformation, airborne grit abrasion, and field debris impact.
- Calibrated Fitment Dimensions (17 x 127 x 14 mm): 17 mm central bore matches standard Iskra / Letrika / MAHLE rotor shafts, while the 127 mm outer profile nests cleanly behind standard drive pulleys.
- Direct Cross-Reference Replacement: Serves as an exact drop-in replacement for original references Iskra/Letrika MGX757 / MGX 757 and Cargo 133874.
Technical Specifications & Dimensions
| Commercial Part Number |
37915900156 |
| Brand / Manufacturer |
MAHLE (Letrika / Iskra range) |
| Original Equipment References (OEM) |
MGX757, MGX 757, 133874, 11.209.156 |
| Component Classification |
External alternator cooling fan / impeller flywheel |
| Operational Rotation Direction |
Clockwise (↻ / CW) |
| Dimension A (Center Bore Diameter) |
17.00 mm |
| Dimension B (Total Outside Diameter) |
127.00 mm |
| Dimension C (Overall Height / Depth) |
14.00 mm |
| Material |
Corrosion-resistant stamped pressed steel |
| Primary Alternator Family |
MAHLE / Letrika / Iskra alternator platforms with Ø 17 mm rotor shaft (IA, AAG, AAK series) |
OEM Cross Reference Table & Applications
| Manufacturer / Brand |
Interchangeable Reference Numbers |
| MAHLE / ISKRA / LETRIKA |
MGX757, MGX 757, 11.209.156, 11209156 |
| CARGO |
133874 |
| Equipment Types |
Agricultural tractors, combine harvesters, telescopic handlers, and stationary industrial engines fitted with external fan-cooled alternators |
Installation Advice & Workshop Notes: Inspect the 17 mm rotor shaft extension for rust, burrs, or scoring before installing the new fan. Position the fan with the cupped vanes directed toward the alternator drive end-frame to ensure correct airflow under clockwise (↻) rotation. Verify axial clearance between the fan vanes and the front housing before torquing the rotor shaft nut to factory specifications, confirming that the fan spins freely without rubbing against the housing.
