How do you loosen the serpentine belt tensioner on a 2002 Nissan Altima to replace belt?

The 2002 Nissan Altima's serpentine belt tensioner doesn't use a conventional bolt to loosen. Instead, it's a spring-loaded mechanism that requires a specific tool or technique to relieve tension. You'll need to use a serpentine belt tensioner tool, sometimes called a tensioner wrench. This tool is specifically designed to fit the pulley and apply pressure to release the tension on the belt.

Without the proper tool, you risk damaging the tensioner or injuring yourself. Trying to pry it with screwdrivers or other makeshift tools is strongly discouraged.

Here's the general procedure (always consult your vehicle's repair manual for specific instructions and diagrams):

1. Locate the tensioner: It's usually located near the alternator or power steering pump. Your repair manual will show you the exact location.

2. Identify the tensioner wrench size: The size and shape of the wrench needed will vary. Check your repair manual or search online for "2002 Nissan Altima serpentine belt tensioner wrench" to find the correct size. Auto parts stores should have them.

3. Position the wrench: Carefully position the tensioner wrench onto the tensioner pulley.

4. Apply pressure: Turn the wrench in the direction that *releases* the tension on the belt (again, your repair manual will indicate this. It usually involves turning the wrench to rotate the pulley away from the belt). This will require some force.

5. Remove the belt: Once the tension is released, you should be able to easily slip the belt off the pulleys.

6. Install the new belt: Install the new belt in the reverse order, making sure to route it correctly over all the pulleys. Consult your repair manual or a diagram to ensure proper routing.

7. Release tensioner wrench: Once the belt is in place, slowly release the pressure on the tensioner wrench.

8. Check belt tension: After reinstalling the belt, make sure the tension is correct. You should be able to twist the belt about 90 degrees between pulleys.

Important Considerations:

* Repair Manual: Having a repair manual specific to your 2002 Nissan Altima is crucial. It provides detailed diagrams, torque specifications, and safety precautions.

* Safety: Always use safety glasses and gloves when working on your vehicle.

* Jack Stands: Properly support your vehicle with jack stands before working underneath. Never work under a car supported only by a jack.

* Torque Wrench: Use a torque wrench to tighten any bolts back to their manufacturer's specified torque.

If you are not comfortable performing this repair yourself, take your vehicle to a qualified mechanic. Improperly tensioning the serpentine belt can lead to premature wear and tear or even belt breakage.