Hub alternator fan. Porsche 356 › 53906201

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

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Billet aluminium black fan pulley half.

Replacement for 96410651102, 93010650900, 93010651000,

Fits:
Porsche 964 1989-94
Porsche 993 1995-98

CNC machined from 7075 aircraft alloy and hard anodized for wear. These pulleys are half the weight of the factory part, spin true and make an awesome appearance upgrade.

Related reference numbers
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RS-164B

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RS Conversion Fan Hub 

Transform your Porsche engine bay with this OE Match RS Conversion Fan Hub, designed to convert the standard dual-belt cooling fan system fitted to the Porsche 964 and Porsche 993 into the single-belt arrangement used on the factory Carrera RS models.

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

Precision CNC machined from 6061 aircraft-grade aluminium and finished in a durable gloss black anodised coating, this premium-quality conversion hub combines motorsport-inspired appearance with exceptional strength and reliability. It provides a clean, simplified engine bay while reducing the number of drive belts, closely following the design philosophy used on the factory RS models.

Supplied complete with all the necessary fasteners, this OE Match conversion hub is ideal for RS-style engine builds, restorations and enthusiasts looking to enhance both the appearance and functionality of their air-cooled Porsche.

What Does the RS Conversion Fan Hub Do?

The RS Conversion Fan Hub replaces the original twin-belt fan drive arrangement with a single-belt configuration, replicating the system used on factory Porsche 964 RS and 993 RS models.

The conversion offers several advantages:

• Converts the standard dual-belt system to a factory RS-style single-belt drive.
• Simplifies the cooling fan drive assembly.
• Reduces the number of rotating components.
• Creates a cleaner, more purposeful engine bay.
• Maintains precise cooling fan alignment.
• Provides dependable operation under both road and performance driving conditions.

The result is a cleaner engine appearance combined with a proven factory-inspired cooling system layout.

Why Upgrade to an RS Conversion Fan Hub?

Many Porsche owners choose the RS-style single-belt conversion during engine rebuilds or restorations to recreate the appearance and engineering of Porsche's iconic Carrera RS models.

Benefits include:

• Factory RS-inspired appearance.
• Simplified belt arrangement.
• Reduced maintenance compared to the standard twin-belt setup.
• Ideal upgrade during engine rebuilds.
• Perfect for RS tribute and lightweight builds.
• Premium CNC-machined construction.
• Improved engine bay aesthetics.
• High-quality corrosion-resistant finish.

Whether restoring a classic air-cooled Porsche or building an RS-inspired road or track car, this conversion provides the ideal finishing touch.

Premium Engineering

Designed to deliver exceptional strength, precision and long-term reliability.

Benefits

Installing this RS Conversion Fan Hub provides:

• Authentic factory RS appearance.
• Cleaner, simplified engine bay.
• Lightweight aircraft-grade aluminium construction.
• Long-lasting anodised finish.
• Reliable cooling fan drive.
• Excellent fit and dimensional accuracy.
• Straightforward installation.
• Ideal for restoration, fast road and track applications.

Installation Recommendations

Professional installation is recommended.

During installation it is advisable to inspect or replace:

• Cooling fan.
• Alternator.
• Fan housing.
• Fan strap.
• Drive belt.
• Pulley components.
• Bearings.
• Mounting hardware.
• Engine cooling shims.

Replacing associated components during installation helps maximise reliability and ensures the cooling system performs as intended.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99310605180

The product you are viewing cross references to these numbers

Alternator pulley spacer.

Fits:
Porsche 964 3.6L  M64.01 / 64.02 Engines
Porsche 993 1995-08

Diagram ref no 17

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

96410621133

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