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- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
- Porsche 993 (911) TURBO 1994-96
- Porsche 993 (911) GT2 1994-97
- Porsche 993 (911) TURBO S 1994-97
Alternator Fan Bearing
Maintain the reliability of your Porsche's charging and
engine cooling systems with this OE Match Alternator Fan Bearing,
suitable for Porsche 964 and Porsche 993 models. This precision-engineered
bearing supports the alternator and engine cooling fan assembly, ensuring
smooth operation while allowing the cooling fan to rotate efficiently at high
engine speeds.
Fits:
- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
- Porsche 993 (911) C2 1994-97
- Porsche 993 (911) C4 1994-97
- Porsche 993 (911) C2S 1994-97
- Porsche 993 (911) C4S 1994-97
- Porsche 993 (911) TURBO 1994-96
- Porsche 993 (911) GT2 1994-97
- Porsche 993 (911) TURBO S 1994-97
Diagram ref no 25
On air-cooled Porsche engines, the engine cooling fan is one of the most critical components for temperature control. The alternator fan bearing allows the fan and alternator assembly to rotate freely while supporting the loads generated by the fan belt and engine speed. A worn or failing bearing can lead to excessive noise, reduced cooling efficiency and, in severe cases, catastrophic damage to the fan and alternator assembly.
Manufactured to OE Match standards, this replacement bearing is ideal for preventative maintenance, engine rebuilds and alternator refurbishment projects.
What Does the Alternator Fan Bearing Do?
The alternator fan bearing is located within the alternator and cooling fan assembly.
Its primary functions include:
- Supporting the alternator shaft
- Allowing smooth fan rotation
- Maintaining fan alignment
- Reducing friction within the assembly
- Supporting high engine speed operation
- Ensuring efficient engine cooling
- Helping maintain charging system reliability
Because the engine cooling fan is directly driven by the crankshaft belt system, the bearing operates continuously whenever the engine is running.
Why Do Alternator Fan Bearings Fail?
Over time, bearings are subjected to significant mechanical loads and temperature fluctuations.
Common causes of failure include:
- Age-related wear
- High mileage operation
- Heat cycling
- Bearing grease degradation
- Contamination from dust and debris
- Excessive belt tension
- Corrosion
- Long-term vibration
As the bearing wears, internal clearances increase and smooth operation deteriorates.
Symptoms of a Worn Alternator Fan Bearing
Common warning signs include:
- Whining or rumbling noises from the fan housing
- Grinding sounds from the alternator area
- Fan vibration
- Excessive shaft play
- Reduced cooling fan efficiency
- Alternator noise
- Difficulty maintaining charging performance
- Visible bearing wear during inspection
Ignoring these symptoms can eventually result in bearing seizure and costly component damage.
When Should the Alternator Fan Bearing Be Replaced?
Replacement is recommended when:
- Rebuilding the alternator
- Refurbishing the cooling fan assembly
- Engine-out servicing is being carried out
- Bearing noise is present
- Excessive shaft play is detected
- Performing preventative maintenance
- Completing an engine rebuild
- Restoring a Porsche 964 or 993
Many Porsche specialists replace the bearing whenever the alternator assembly is removed for major servicing.
Why Replacement Matters
Replacing a worn fan bearing helps protect both the engine cooling system and charging system.
Benefits include:
- Smooth fan operation
- Improved cooling system reliability
- Reduced noise
- Improved alternator performance
- Protection against costly failures
- Better engine temperature management
- Long-term durability Enhanced reliability
For air-cooled Porsche engines, maintaining the cooling fan assembly is essential for engine longevity.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
96410605131
The product you are viewing cross references to these numbers
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT2 2007-09
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Fits:
Porsche 987 Boxster 2005-08 (I480 / I481)
Porsche 987C Cayman 2005-08 (I480 / I481)
Porsche 997 MKI Carrera 2005-08 (I480)
Porsche 997 Turbo 2007-09 (I480)
Porsche 997 GT2/RS 2010>>
* I480 - 6-speed Manual Transmission
* I481 - 5th-speed Manual Transmission
Diagram ref no 21
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99760315401
The product you are viewing cross references to these numbers
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT2 2007-09
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Fits:
Porsche 987 Boxster 2005-08 (I480 / I481)
Porsche 987C Cayman 2005-08 (I480 / I481)
Porsche 997 MKI Carrera 2005-08 (I480)
Porsche 997 Turbo 2007-09 (I480)
Porsche 997 GT2/RS 2010>>
* I480 - 6-speed Manual Transmission
* I481 - 5th-speed Manual Transmission
Diagram ref no 21
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99760315401
The product you are viewing cross references to these numbers
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT2 2007-09
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Restore smooth and reliable operation of the auxiliary drive system with this Valeo Alternator Belt Pulley with Free Wheel Lock. Valeo is a recognised Original Equipment supplier of automotive electrical and drive-system components, producing high-quality parts designed for accurate fit, dependable performance, and long service life.
Fits:
- Porsche Boxster 987 2.7L 2005-08/08
- Porsche Boxster 987 S 3.2/3.4L 2005-08/08
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT2 2007-09
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
I480 - 6-Speed Manual Transmission
I481 - 5th-Speed Manual Transmission
Diagram Ref No 21
The alternator pulley transfers drive from the auxiliary belt to the alternator while its integrated freewheel/overrunning mechanism allows controlled rotational movement between the alternator and engine. This helps isolate the alternator's rotating mass from rapid changes in engine speed, reducing belt vibration, tension fluctuations, and shock loads throughout the auxiliary drive system.
What This Product Does:
- Transfers auxiliary belt drive to the alternator.
- Allows the alternator to freewheel or overrun when required.
- Helps absorb rapid changes in engine rotational speed.
- Reduces vibration and oscillation within the auxiliary belt.
- Helps stabilise belt tension during engine speed changes.
- Reduces shock loading on the alternator and belt-drive components.
- Helps protect the auxiliary belt, tensioner, and alternator bearings.
- Provides an OE-quality fit for reliable replacement.
Symptoms Of Wear Or Failure:
- Excessive auxiliary belt vibration.
- Belt tensioner visibly bouncing or oscillating.
- Squeaking, chirping, rattling, or knocking from the belt area.
- Pulley failing to freewheel correctly.
- Pulley seized in both directions.
- Excessive pulley play or wobble.
- Roughness when rotating the pulley.
- Premature auxiliary belt wear.
- Unusual noises when the engine is switched off.
- Increased vibration at idle.
- Alternator bearing or tensioner wear associated with excessive belt loads.
Why Replacement Matters:
- The alternator freewheel pulley plays an important role in controlling vibration and rotational loads within the auxiliary drive system. Unlike a conventional fixed pulley, its overrunning mechanism allows the alternator rotor to continue rotating momentarily when engine speed drops rapidly. This prevents the alternator's rotational inertia from repeatedly pulling against the auxiliary belt.
- If the freewheel mechanism seizes, wears, or develops excessive play, increased vibration and shock loads can be transmitted through the belt system. This may cause accelerated wear of the auxiliary belt, tensioner, idler pulleys, and alternator bearings. A severely worn pulley can also affect belt tracking and potentially contribute to belt failure.
- Replacing a worn or faulty component with this Valeo Alternator Belt Pulley with Free Wheel Lock 99760315401/2 restores correct overrunning operation, reduces auxiliary belt vibration, and helps protect surrounding drive-system components. Manufactured to Valeo's high-quality standards, this pulley provides accurate fit, smooth operation, and dependable long-term performance for Porsche maintenance and repair.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99760315401
The product you are viewing cross references to these numbers