An alternator — commonly referred to as a power generator in parts catalogues — converts mechanical energy from the crankshaft into the alternating current that charges the battery and powers every electrical circuit while the engine runs. Without it, a fully charged battery will typically sustain the car for twenty to forty minutes before the ignition system, fuel pump, and ECU lose power entirely. The most common failure mode is a worn or glazed slip ring, which causes the output voltage to drop intermittently before collapsing, often showing up as a battery warning light that flickers at idle then steadies at higher revs. Bearing failure is the second culprit, announcing itself through a high-pitched whine from the front of the engine that changes pitch with engine speed. Alternators are chassis-specific in their mounting geometry, pulley ratio, and amperage rating, so matching the OE number ensures you receive a unit calibrated for your vehicle's electrical load rather than a generic equivalent. Bosch and Valeo manufacture the majority of original-equipment units fitted to European cars, and their catalogue replacements carry identical OE references. Output capacity typically ranges from 90 A on small petrols to over 180 A on diesel estates with multiple comfort systems.
Every alternator listed here carries the OE numbers TecDoc maps to specific engine and chassis combinations. Start by using your vehicle's make, model, and year in the selector, then cross-check the part number stamped on your existing unit — usually on a label or cast into the casing near the rear cover. The OE reference encodes the mounting bracket pattern, pulley diameter, amperage rating, and connector type, so an exact match prevents any wiring or bracket modifications at fitting time.
OEM alternators are produced to the vehicle manufacturer's original specification by suppliers such as Bosch or Valeo and carry the same OE number. Quality remanufactured units are stripped, cleaned, and rebuilt with new bearings, brushes, and slip rings to equivalent tolerances. New aftermarket alternators occupy a middle tier — different internal architecture but correct output specification. Remanufactured units cost less and are environmentally preferable, though their warranty period is typically shorter than a new unit.
On some designs, particularly older Bosch and Valeo units with accessible brush holders, replacement brushes are available separately and represent a cost-effective repair. However, if the slip rings are also worn or the bearings are noisy, partial repair often leads to a repeat failure within months. Where the full unit is worn or the vehicle has high mileage, replacing the complete assembly is generally the more reliable outcome, and total labour time is usually the same either way.
The earliest sign is usually a battery warning light that appears at idle and extinguishes above 1,500 rpm, indicating the alternator is producing insufficient voltage at low speed. A grinding or whirring noise from the front of the engine that varies with engine speed points to worn internal bearings. Dimming headlights and a sluggish electric window are signs of reduced output. In advanced failure, the battery drains fully while driving, electronics begin resetting, and the engine eventually stalls.
Showing 100 of 55,343 Power generator OE numbers. Enter the OE on the main OE search to jump to any reference.
