How to Replace an Air Injection Pump Belt

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

How to Replace an Air Injection Pump Belt 2

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

How to Replace an Air Injection Pump Belt 3

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

How to Replace an Air Injection Pump Belt 4

  • Note: Some tensioners have a slot for inserting a ⅜” ratchet head end into while others have a traditional bolt head.

How to Replace an Air Injection Pump Belt 5

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

How to Replace an Air Injection Pump Belt 6

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

How to Replace an Air Injection Pump Belt 7

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

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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

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

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

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

Part 5 of 5: Install the v-belt

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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.

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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.

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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.


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John

27 years of experience
857 reviews
John
27 years of experience
Mercedes-Benz GLK350 V6-3.5L - Serpentine/Drive Belt - Pearland, Texas
Highly highly highly recommend John. He is truly the most honest hard working man that I’ve met. He treats you like family. He fixed my Benz in a timely manor. He is nice and will go the extra mile to ensure your happiness.
Nissan Versa Note - Serpentine/Drive Belt - Houston, Texas
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Greg

22 years of experience
155 reviews
Greg
22 years of experience
Acura RDX L4-2.3L Turbo - Serpentine/Drive Belt - Mesa, Arizona
Greg was awesome!! Very polite, helpful, knowledgeable and efficient. I will be requesting Greg for repairs on other vehicles. I am also recommending him to friends, family and Co workers.
Honda Civic - Serpentine/Drive Belt - Chandler, Arizona
He was honestly a great person and worker. He checked my car before working on the order that I put in and was able to see the real problem with the car. Would definitely recommend him to others . And will be using this service again

James

31 years of experience
611 reviews
James
31 years of experience
Hyundai Tucson L4-2.4L - Serpentine/Drive Belt - Buena Park, California
James was very professional and surprisingly "on time". It is so refreshing. We will definitely request more work in the future.
Toyota Tacoma - Serpentine/Drive Belt Replacement - Yorba Linda, California
James was on time and definitely knew what he was doing. Went over the truck, checked and inflated tires, checked coolant etc.

Kyle

12 years of experience
70 reviews
Kyle
12 years of experience
Hyundai Elantra L4-2.0L - Serpentine/Drive Belt - Las Vegas, Nevada
Kyle was friendly and on time. Recommend other services that my car may need in the future. I will differently call again.

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