Chevrolet Forum - Chevy Enthusiasts Forums

Chevrolet Silverado 2007-2013: How to Replace Idler and Tensioner Pulley

Don't just sit there idle or get tense about things. Let's replace your idler pulley and tensioner to set things right under the hood of your Silverado.

By James Hodgson - July 13, 2015

This article applies to the Chevrolet Silverado 1500 (2007-2013).

Your drive belt uses the engine's power to run your accessories. Things like power steering, A/C, and your alternator all need it. In order for it to work properly it needs to be properly tightened, without any nasty stuff like bad bearings in the idler pulley or a shot spring in the tensioner. We'll check for those problems and fix them if need be.

Materials Needed

  • Box end wrench set
  • Socket set

On the fan shroud in your engine compartment you should see a diagram of how the belts are supposed to run around all the accessories. Give it a glance before you start so you know which one is right for your engine. You'll need to make sure you get the belt back in the right place later on and this diagram will help.

Figure 1. This diagram will help to show the various systems used by the pulleys.

Step 1 – Release tension on the drive belt and remove the belt

Referring to Figure 1, release the pull on the tensioner pulley by using a wrench to turn the big bolt head in the middle of it. Some other ones, as shown at the right in Figure 1, have a square hole meant to accept a 3/8 drive wrench directly. In either case, apply force to it until you're able to slip the belt off.

Your drive belt has what's known as a tensioner on it. It's a pulley on a spring that pulls against the belt, making it tight. It might not look exactly like the image above, depending on your engine size, or possibly whether you have power steering or A/C. You'll know it because it will be a pulley that doesn't have a lot of machinery behind it. If the pulley isn't springing back eagerly when you release it to take the belt off, that's strong evidence that it needs replacing.

Figure 2. How to move the tensioner.

Step 2 – Spin the idler pulley with your hand and check for grinding sounds

The idler pulley should spin easily with the belt off. Its only job is to help move the belt along, so if you spin it with your hands and there's any grinding or noise, that's a problem. The idler is easy to replace. Just unbolt the old one and put the new one back on.

The idler pulley might look like this. Again, it depends on your engine and accessories, or lack thereof.

Figure 3. Idler and bolt orientation for 2004 Silverado.

Step 3 – Put the belt back on and verify visually that it is turning nice and smoothly

For this part you're going to want to start up your truck with the hood open and visually inspect the motion of the drive belt as it is running. Be sure to keep fingers, curious pets, and wild children away from the engine so they don't get hurt. Make sure the belt is turning nice and smoothly on the accessories. Is your power steering working? Does the A/C blow nice and cold? Are you seeing good power output from the alternator? If all those are true and you are squeak and grinding noise free, then you're done!

Figure 4. Make a last check of all the accessories for proper function.

Featured Video: Silverado Removing Idler and Tensioner Pulleys

Related Discussions