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How To Replace Serpentine Belt Tensioner 99-04 GMC Sierra 2500

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How To Replace Serpentine Belt Tensioner 99-04 GMC Sierra 2500

Created on: 2021-01-16

Watch this video and learn how to replace the serpentine belt tensioner on your 99-04 GMC Sierra 2500

  1. step 1 :Remove the intake hose
    • Use your screwdriver to pry back the clip and break the seal on the intake hose.
    • Move it out of the way and set aside.
  2. step 2 :Remove the serpentine belt
    • Use your 15 mm socket and ratchet to release the tension from the belt tensioner pulley
    • Pull the serpentine belt off the engine.
  3. step 3 :Remove and install the new serpentine belt tensioner.
    • Check your pulleys for play, squeaking, rattling, or grinding sounds.
    • Unbolt the 15 mm bolts anchoring the tensioner pulley.
    • Replace with the new pulley from 1A Auto and bolt into place.
    • Torque to 330-35 ft lbs.
    • Use your serpentine belt diagram and the 15 mm socket and ratchet to thread the serpentine belt onto the pulleys, releasing the tension from the tensioner pulley to get the belt over the last pulley.

Tools needed for replacement

  • Ratchets & Related

    Socket Extensions

    Ratchet

  • Screwdrivers & Related

    Flat Blade Screwdriver

    Phillips Head Screwdriver

  • Sockets - Metric

    15mm Socket

Installation Video
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Brought to you by 1AAuto.com, your source for quality replacement parts and the best service on the internet. Hi, I'm Mike Green, I'm one of the owners of 1A Auto. I want to help you save time and money, repairing and maintaining your vehicle. I'm going to use my 20 plus years experience restoring and repairing cars and trucks like this. To show you the correct way to install part from 1AAuto.com. The right parts, installed correctly. That's going to save you time and money. Thank you and enjoy the video.

In this video, we're going to replace the serpentine belt tensioner on this 2002 Sierra with a six liter. The same procedure for any GMC or Chevy truck, 99' to 07' basically. With 4.8, 5.3, or six liter v8's. Tools you'll need, flat blade screwdriver, 15mm socket and ratchet with a small extension. Symptom of a bad belt tensioner is a squeaking from the front of your engine. Could also be your idler pulley. Just check out our other video to see the idler pulley removal and installation. First you want to move your intake hose. By removing, or loosening two clamps, one there and one there. We're going to speed up through this part here. Use your screwdriver to pry in, break the rubber loose and the plastic, Maybe twist it a little bit as well. Then pull it from the throttle body and also pry ... there's a little clip that hold the radiator hose in, pry that out with your screwdriver as well. Now I'm going to install it back on my intake hose, to make it easier for later.

Now you can see your tensioner is right here. What you're going to do is take a 15mm socket and ratchet and put the socket on there. Then that takes the ... you just move the ratchet clockwise and that takes the tension off. You can pull the belt either off of your tensioner or I'm actually over here pulling it off of the idler pulley in the middle. Then slowly release this back. It's going to actually go back further than the original point. Now get your wrench back off. Once you have your belt off, many times you can reach in here and spin these and hear some grinding or shaking, or shake them back and forth and you can there's some play in that pulley. This is your idler pulley here. Many times there is play, this one feels actually pretty good. There is also another tensioner on this vehicle. It's for the AC belt and you can see it right down in there.

You can see that belt is actually looking a little cracked, so I'm going to replace that as well. That will be on a different video, but that's something to keep in mind. You may take your drive belt off and realize that these ones really aren't the problem. Your noise might be coming from the AC tensioner down there. You can check out our other video to see that. To remove your tensioner there's three bolts. You can see one here, one down lower, and then there's one right down below there. Those are 15mm bolts. I'm going to use a 15mm socket with an extension and a ratchet and remove these bolts. I'm going to really speed through taking these bolts off. You don't really need to see me working a ratchet. Pretty all surprised on this truck, truck has got a lot of miles and it doesn't look like this has been replaced before. The bolts came loose pretty easy.

Then, as you probably see here, I actually used my fingers to loosen them or take them out most of the way. Here I am just removing the last top bolt. Now the tensioner comes up and out. Here you can see, here's the original tensioner, new tensioner from 1A Auto. All the same, going to mount the same. What I usually like to do is ... that actually goes in like that. Take our top bolt, put it in, put it down in, and start that top bolt. Take our bottom, long bolt, put it in, start it. Then our third bolt that's way down on the bottom, put it in and start, and then tighten them up. Once again, we'll fly through me just tightening these three bolts. When you tighten the bolts you want to probably give them a final tightening 30 to 35 foot pounds. To put the belt back on, what you want to find is your routing diagram.

We're going to be using this one right here. The solid belt is the one that we're going to be looking at. What you're going to do is actually feed it down and around your crank pulley first. Then up and over your water pump, around your power steering, and then up in here. Then you'll pull, what I usually do is pull on here and then pull it up onto the alternator. I'll show you that, you can't really film it very well, so you'll have to take ... Of course, I can't really film it that well, so you have to take my word for it that that's what I'm doing. You can take your belt, feed it down, feed it down, and just make a loop. Make sure it goes all the way around your crank pulley, over the water pump here, and down and around the power steering pump. First I went down and around my crank pulley, up and around the water pump, with the back side of the belt. Then around the power steering pump. Now I have this part that I can hold to put onto the alternator.

I'm just going to set it there for a second. Took my socket, put it on my 15mm bolt on my tensioner. Then while I pull this way on the tensioner, I'll take the belt and pull it up and onto the alternator. Then the tensioner takes over and I'm just going to push it on a little more to my idler pulley here. Make sure it's pretty well centered. After you have the belt on, just a quick check, make sure it's on all the pulleys. Look way down at the crank pulley and make sure that it's on correctly down there. Also, obviously over here, the alternator and the power steering pulley. Everything looks good. We're going to fast forward though this section, which is just putting that tube back in basically, and pushing the rubber onto the plastic. Tightening up the clamps and reinstalling that little clip that held the radiator hose to it. After that you should be pretty much all set.

We hope this helps you out. Brought to you by www.1AAuto.com, your source for quality replacement parts and the best service on the internet. Please feel free to call us toll free 888-844-3393. We're the company that's here for you on the internet and in person.

Tools needed for replacement:

    Ratchets & Related

  • Socket Extensions
  • Ratchet

  • Screwdrivers & Related

  • Flat Blade Screwdriver
  • Phillips Head Screwdriver

  • Sockets - Metric

  • 15mm Socket

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