Refer to the official diagram below for the 2008 Nissan Altima accessory drive belt routing. This engine configuration uses a single serpentine belt.
Official Belt Routing Diagram
Engine: QR25DE (2.5L 4-cylinder)
- The belt wraps around the following components, starting from the crankshaft pulley:
- Crankshaft Pulley
- Air Conditioning Compressor Pulley
- Idler Pulley (Smooth, fixed position)
- Power Steering Pump Pulley
- Alternator Pulley
- Automatic Tensioner Pulley (Grooved)
Replacement Procedure
- Identify & Release Tensioner: Locate the spring-loaded automatic tensioner pulley. Using a suitable socket/wrench on the tensioner's square drive or protrusion, rotate it clockwise against spring pressure to create slack.
- Remove Old Belt: Slip the old belt off the pulleys while maintaining tensioner pressure. Note the routing path.
- Install New Belt: Place the new belt over all pulleys except the tensioner pulley, following the diagram precisely. Ensure correct rib engagement in all pulley grooves.
- Final Step: Rotate the tensioner clockwise again to create slack. Slide the belt onto the tensioner pulley. Slowly release the tensioner.
- Verify: Confirm the belt is fully seated in all grooves. Start the engine briefly to check for smooth operation and unusual noise.
Important Notes
- Safely Relieve Tensioner Pressure: Do not let the wrench slip; sudden release can cause injury or damage.
- Belt Path is Critical: An incorrect route leads to immediate failure.
- Use Correct Belt: Verify the new belt matches the OE specification for length and rib count (typically 6PK).
- Tension Check: The automatic tensioner handles tension; manual adjustment isn't required.
- Inspect Components: Before installing a new belt, check all pulleys for smooth rotation (no grinding or wobble) and inspect the tensioner arm for proper spring action.