This tensioner (or idler) pulley is designed for Porsche 911 (996/997) and Boxster/Cayman vehicles. It supports the serpentine/drive belt system, ensuring smooth, stable rotation and correct belt alignment. It helps maintain proper tension, reduces noise, and protects engine accessories from excessive stress. Built to original Porsche standards and engineered for precise fitment and durability.
Fits:
Porsche 996 Carrera 3.4L / 3.6L 1997-05 6-speed Manual transmission
Porsche 997.1 Carrera 3.6L / 3.8L 2005-08 Manual transmission
Porsche 987.1 Boxster 2.7L / 3.2L / 3.4L 2005-08 Manual transmission
Porsche 987C.1 Cayman 987C 2.7L / 3.4L 2005-08 Manual transmission
Diagram ref no 15
Ideal replacement when the original pulley shows signs of wear, bearing noise, belt misalignment or visible belt damage - restoring accessory-drive reliability and avoiding secondary damage from belt failure.
The idler pulley plays a critical role in your accessory belt drive, maintaining the correct path and tension of the belt that powers many engine-mounted systems. When the pulley bearing deteriorates, or the surface becomes worn or grooved, the belt can slip, make noise, or even break—potentially causing loss of alternator, AC compressor or power-steering function. By replacing this component proactively with a quality OE-Match unit, you safeguard those systems and maintain proper engine accessory operation.
When and why to replace:
• Audible bearing noise or rumble coming from the pulley/belt area.
• Visible belt wear, glazing, fraying or mis-tracking across the pulley surface.
• Occasional belt slippage or accessory drive belt squeal on start-up or load.
• Accessory drive servicing (belt replacement, tensioner replacement) where it makes sense to fit the pulley at the same time.
• Higher-mileage vehicle where original pulley may have been in service for many years and bears may be near end-of-life.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99710211800
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 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- 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 Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08

