The air injection system introduces oxygen into the exhaust to reduce emissions. The heart of the air injection system is the air pump, or smog pump.

Most modern air pumps are electric, but older ones are belt-driven. The belt can be either a v-belt or serpentine belt design. Over time, the air pump belt may wear out or show signs of malfunction. Here is a guide on what to do when it's time to replace it.

Part 1 of 5: Prepare to replace the air injection pump belt

Materials Needed

Step 1: Locate the belt routing diagram. Before you remove the old belt, locate the belt routing diagram. This will help you install the new belt correctly.

Most of the time, the belt routing diagram can be found inside the engine compartment. If it is not, consult the repair manual for your vehicle for it.

Part 2 of 5: Remove the serpentine belt if equipped

Step 1: Move the tensioner. Use a ratchet or dedicated serpentine belt tool to push or pull the tensioner away from the belt.

  • Note: Some tensioners have a slot for inserting a ?” ratchet head end into while others have a traditional bolt head.

Step 2: Remove the belt. While still holding the tensioner in place, slide the belt off the pulleys.

Part 3 of 5: Install the serpentine belt

Step 1: Consult the belt routing diagram. Consult the belt routing diagram and ensure that you know how to install the belt correctly.

Step 2: Move the tensioner. Push or pull on the tensioner so that the new belt can be positioned on the pulleys.

Step 3: Install the belt. Slide the new belt onto the pulleys and let go of the tensioner.

Double check the belt diagram to ensure that your new belt is routed correctly.

Part 4 of 5: Remove the v-belt if equipped

Step 1: Loosen the mounting bolts. Loosen the pump mounting bolts and/or adjustment bracket bolts but do not remove them.

Step 2: Move the pump. Move the pump inward until the belt can be removed.

Step 3: Remove the belt. Slide the belt off the pulleys.

Part 5 of 5: Install the v-belt

Step 1: Install the new belt. Consult the belt routing diagram to ensure that you know how to install the belt. Install the belt over the pulleys.

Step 2: Put the pump back. Move the pump back into place. The belt should have about ½” of deflection if the belt is properly tensioned.

Step 3: Tighten the pump mounting bolts. Tighten the pump mounting bolts and/or adjustment bolts down until they are snug.

Double check the belt routing diagram to verify that the belt is routed correctly.

You should now have a nice new air pump belt installed. If this seems like something you’d prefer to leave to the professionals, YourMechanic offers an expert air pump belt replacement service.

This article originally appeared on as How to Replace an Air Injection Pump Belt and was authored by Mia Bevacqua.

Share This Photo X