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How to Replace AC Belt 04-07 Subaru Impreza WRX

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How to Replace AC Belt 04-07 Subaru Impreza WRX

Created on: 2018-03-06

How to repair, install, fix, change or replace a broken, noisy, squeaky, worn or groaning serpentine belt tensioner on 04, 05, 06, 07 Subaru Impreza WRX.

Tools needed for replacement

  • General Tools

    Wire Brush

  • Materials, Fluids, and Supplies

    Rust Penetrant

    Brake Parts Cleaner

  • Ratchets & Related

    Socket Extensions


  • Sockets - Metric

    12mm Socket

Installation Video
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Hi, I'm Mike from 1A Auto. We've been selling auto parts for over 30 years.

Remove the belt cover here. We'll spray some rust penetrant on this bolt and nut and a little bit on this nut, little bit on this bolt here. Use a 10 millimeter socket extension and ratchet. Remove this one. Remove this one here. Take the nut off. Remove this cover. Just pull it off. It does have the throttle cable and the cruise control cable clipped to it. Pull it up. Unclip it. It pulls straight up. Normally, that's clipped in there. Just over time it's gotten old and cracked. The clip came right out. Alright, we'll flip this over and push that one out. We can just put this aside.

This particular vehicle doesn't use an auto tensioner for the belts. It has two separate drive belts, both with manual tensioners. You need to adjust these and set your belt tension and the same for the other one down here that runs the air conditioning pulley. These belts feel fairly tight, but they are squealing. The belts do stretch over time. You could try to readjust them, but these are looking pretty worn. They've got a lot of rust staining on them and basically every time you start the car when it's cold, they squeal really loudly. Once they start to squeal, they're ruined. We'll replace them with new belts from 1A Auto and retension them. We'll have brand new belts.

We need to loosen the alternator bolts. Spray some rust penetrant on here. Bolt goes all the way through.

12 millimeter bolts. Just get it loose. Now we can loosen the tensioner.

The tensioner here has two bolts, one to set the tension and the one right here to lock it in place on the bracket. You need to remove, or loosen, actually. You don't need to fully remove it. Just loosen the locking bolt underneath before you try to release the tension, or else it's not gonna move on you and you could break this bracket.

Loosen this bolt using a 12 millimeter socket extension and ratchet. You don't have to take it all the way out. Just get it loose. It goes all the way through into the alternator. That should be good enough. Now I can loosen this.

Make sure that before you loosen the tensioner bolts or attempt to loosen the tensioner bolts that you loosen the alternator bolts. It should make it easier to turn because it's not trying to push against the alternator. Even still after doing this, our tensioner bolt broke because it was frozen into the little bracket piece that is bolted into the alternator. Just make sure that you have an extra bolt on hand if your vehicle is very rusty. It might break. Tensioner loose. Push the alternator down. Pull the belt right off. Slide it in between here. You can see some wear. It's kind of worn smooth. The outside's pretty rough.

If you just wanna replace the alternator power strain belt, you can stop here. But to replace the air conditioning belt, you do need to take off this belt first. Now we can take off the air conditioning belt. There's also a manual tensioner here. There is a tensioner pulley there. I'm gonna spray rust penetrant on that nut because it needs to be loose and on the tensioner rib here. I will clean all of the oil off of the pulleys before I install the new belts. This is a 12 millimeter socket. It'll loosen this nut that's on the tensioner pulley. It's a little rusty. Just finding my way down here. Break this free. This one is just very, very rusty. It is moving. You need to loosen this first 'cause there is a groove here that it slides in to tensions. There, it's nice and loose. We'll work this off. Socket might get stuck on there because of the rust. I'm just gonna wiggle it off. The ratchet's gonna come first. The socket's a little stuck in there. It is pretty close to the fan. I'll slide that out of there. That's okay. I'll work on getting that off.

Gonna take some locking pliers and just go down and try to grab it. At the same time they lock on here. You don't need to crush it. You just need to get enough leverage. There it is.

Now I'm gonna use the 12 millimeter and an extension here. I'll loosen this one. This one's loosening up nice and easily. You can see it's pulling the tensioner up.

You'll start to see the belt get really loose. Not quite there. Looks pretty loose.

It's pretty loose. Just slide it off just like that. It's gonna go down around the tensioner off the crank pulley. It'll pull right off.

This one does have some wearing. It's sliding on the pulleys and making noise. It almost looks like a tire, like he did a burnout with it, the kind of wears.

We're gonna use some brake parts cleaner to clean the pulleys off. We need the rust penetrant I sprayed on there.

There's little bits of rubber here that are stuck inside the pulley that have worn off from the belt. You can use a wire brush to break them free, clean them out of there. Just go around the pulley. If you have access to compressed air, you can also blow off the pulley. Same for all of them. These should spin freely. The crank one won't really spin freely on you because it's attached to the engine. But just work your way around the outside of the crank pulley as best you can.

Here are some things to look for when you're inspecting your belts. When you're looking at dry belts under the hood of the car, you wanna look for cracks like this in the rubber. This belt is worn out. These little grooves can actually start to fall apart. Then the belt won't have any grooves on it because they're all dry rotted and cracked. The back of it is real dry and worn. There's a little bit of fraying on the edges of this belt. You can feel it in this belt and actually you can see it over here, part of the ribs are starting to fall apart. This belt is really hard. It's not very flexible. It's really past its prime. It needs to be replaced.

This one here, this one was making noise. It was squealing. You can see that it's got worn rubber marks. It looks like a tire, you were doing burnouts or something. You get those worn tire marks and the rubber wears. It also has some fraying around the edges. The grooves are worn. This belt is no good if we compare it to the nice, new belt. It's really flexible. The grooves are nice and thick. They've got plenty of good rubber on them. There's no fraying or anything. The other thing, too, sometimes with a car that has an automatic tensioner, you won't hear the belt squeal as it starts to wear out because the automatic tensioner will take up the slack as the belt stretches, whereas a belt that's on a manual tensioner as it starts to wear, it will start to slip. Once it starts to slip, it ruins the belt. You can try to retension it, but you should really just replace it.

Start with the belt for the air conditioning system. We're gonna slide it down. It goes towards the inside of the crank pulley. There's two sets of grooves. This is gonna go on the inner groove. You also wanna reach it down and over the tensioner bracket.

It's gonna go underneath the tensioner bracket and then up and over. Don't worry about getting in all the grooves yet. You can get it close. Get it set up on the crank pulley first. Make sure it's seated. Start there. It's going around the tensioner pulley. It probably won't be touching it 'cause it's loose. Work it up and over the AC compressor. There it is. It's really loose. Tension's not set, but it is in all of the grooves. Now I wanna set the tension on it. I'm gonna tighten the tensioner bolts. This might take a little while. The bolt's very long. I can see the belt starting to tension. I'm gonna lift up the alternator a little bit. The alternator will not be touching this in the car normally, but I'm just gonna lift it up out of the way. Just make sure I get a good tension on it.

It's something you have to do by feel for a new belt. The specification is about 22 pounds of force. It will deflect seven to nine millimeters. I'm just estimating that by feel as I don't have the factory gauge to check it. Most people aren't going to. You can do it by feel. Don't feel too loose, but they don't feel overly tight. I'm gonna give it one more turn and I'm pretty happy with that. You can always come back and adjust them after you run the car. That feels a lot tighter. I think that's too tight. Back it off just a little bit. I like that there, that tight. I need to tighten the pulley so that the pulley doesn't move.

To work on these is 16 foot-pounds. It's not very heavy, but I'm going to do it by feel. This one is rusty. Don't over-tighten it. Go to 16 foot pounds. That's tight there.

Install the alternator and power steering pump pulley. Get this down in here. Feed it down in the front of the engine. Down around the pulley. Make sure it's seated. The alternator's loose. I can push this down. Go around the power steering pump. It popped off the crank pulley. That's gonna be the trickiest part is getting it to stay on the crank pulley. I wanna do the alternator last. Though, if you have to, you can slide it up over the alternator. Clearance is tight but you can get in here. Sometimes if you make sure it's all the way on one of these other pulleys, it will hook down over the crank. Don't wanna use a pry bar to put these on. To pry the belts on, get my hand down here. I'm gonna hold it near the crank pulley, and then I'm gonna pop it off the top of the alternator pulley and slide it over the crank pulley. I can see it's still over the power steering pump pulley. Gonna push the alternator down a bit and work it on. The alternator doesn't go down far enough, you can loosen this bolt up, push it down a little bit more. That is at the bottom of the bracket.

See, it popped out of the power steering pump bracket pulley. If it's not fully seated in the pulley, it's not gonna have enough give. This is good that the belt is nice and tight 'cause it starts out nice and tight. Just work it over. There it is. It wasn't quite seated in the crank pulley, give it a little tension, trying to put it over the alternator pulley, but now I can see it's in all of the pulleys. It's seated nice and even. Now we can start to tension this back up. You can actually pull this up a bit by hand. So I don't have to thread this forever, I'm gonna thread it down by hand.

Tighten this up.

Again, I'm gonna do that by feel. A bit more. It's the same specification with about 22 foot-pounds. With 22 pounds of force it should be a deflection of seven to nine millimeters. I think I'm happy with that right there. I've got the belt tensioned. Gonna lock our tensioner in place. This is 16 foot pounds. I will do it by feel. Don't over-tighten it. You don't wanna break the ear on the alternator. I think it's tight. I will stop and the final step, we'll lock the alternator in place now. Re-tighten this bolt here, the little extension.

This bracket needs to go straight up and down. Feel that get tight and I'll stop.

You can start the car to check the tension and readjust if necessary.

I'm gonna reinstall the plastic cover. Let's get this little plastic part. It's gonna sit in this rubber mount. Push it down into place. Also feed it over the stud that's over here. Reinstall the screw. Reinstall the nut.

Reinstall this bolt here. Clip our throttle cable, cruise control cables back in. Some later vehicles may not have these.

Thanks for watching. Visit us at for quality auto parts, fast and free shipping, and the best customer service in the industry.

Tools needed for replacement:

    General Tools

  • Wire Brush

  • Materials, Fluids, and Supplies

  • Rust Penetrant
  • Brake Parts Cleaner

  • Ratchets & Related

  • Socket Extensions
  • Ratchet

  • Sockets - Metric

  • 12mm Socket

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