DIY Drive Belt Replacement (Serpentine Belts)
 

DIY Drive Belt Replacement (Serpentine Belts)

Intro:
Here's the complete guide to removing/replacing 03-05 G35 Coupe drive belts. Other years may be similar. During this tutorial, you will be shown how to replace both drive belts. The larger (wider) drive belt powers the alternator and power steering pump. The smaller (thinner) belt powers your air conditioner compressor. Inspect belts for cracks, fraying, wear and oil. If necessary, replace.

Tool List:
3/8" drive ratchet
3/8" drive 6" extension
14mm socket (shallow and deep)
12mm socket
10mm socket
Electric Impact Driver (not required, but makes things go much faster. Use 1/4" ratchet as a substitute)
https://lh5.googleusercontent.com/-n.../WP_000136.jpg

Parts:
Make sure you get the right belts. Depending on the year of your car, the larger (wider) drive belt that powers the alternator and power steering pump comes in different lengths. From what I've read, some of the earlier G models actually had a mechanical fan, which requires a slightly different length belt. If you have any question about what belt to buy, contact your local dealer and they should be able to confirm the length of the belt for your car's year and model. With that information, you will be able to purchase the correct belt. I ordered a set of pretty blue Gates belts for my 03' Coupe. Why blue Gates High-Performance Belts? Because race car. The Gates part numbers are:
PS/Alternator belt- K060465RB
AC Belt- K040372RB
https://lh4.googleusercontent.com/-W.../WP_000121.jpg

1.) Remove the lower plastic undershroud. There are a **** ton of 10mm bolts. Use the impact driver to zip them all out until the undershroud is loose. Now would be a good time to scrub it clean before you reinstall it later. Now you should have a clear view of the underside of the engine.
https://lh3.googleusercontent.com/-B.../WP_000122.jpg
https://lh5.googleusercontent.com/-8.../WP_000112.jpg

2.) Before taking the old belts loose, go up top and tug on both belts. Get a feel for the tension, so that when you install the new belts, you have an idea how the new belts should feel when installed.

3.) When looking under the car, you can see each of tensioner/idler pullies. The tensioner on the left side of the picture (the 2 red circles) is for the larger drive belt that powers the alternator and power steering pump. The upper bolt (upper red circle) must be loosened first to release the pulley, and then the tension bolt (lower red circle) bolt can then be loosened to release the tension on the belt.

The same applies for the smaller (thinner) belt that powers your air conditioner compressor. The tensioner is located on the right side of the picture (the 2 blue circles). The upper bolt (upper blue circle) must be loosened first to release the pulley, and then the tension bolt (lower blue circle) bolt can then be loosened to release the tension on the belt. These steps are done in reverse order when putting on the new belts.
https://lh3.googleusercontent.com/-b...pulley+pic.jpg

4.) Use a short 14mm socket to loosen the larger PS/ALT belt's idler pulley.
https://lh3.googleusercontent.com/-n.../WP_000126.jpg

Then loosen the tensioner bolt using the 12mm socket with extension. Now remove the belt. One way to try and get the belt tension close on the new belt, is to count the number of full turns that you loosen the tensioner bolt when you take the old belt off. When you put the new belt on, tighten it the same number of turns it took you to remove the old belt. That should at least get you close to the proper belt tension.
https://lh3.googleusercontent.com/-H.../WP_000116.jpg

4.) Use a deep 14mm socket to loosen the smaller A/C belt's idler pulley.
https://lh3.googleusercontent.com/-I.../WP_000124.jpg

Then loosen the tensioner bolt using the 12mm socket with extension. Now remove the belt.

At this point, all the old belts are removed, and you are ready to install the new belts. This is a good time to check all the pulleys. Rotate each pulley by hand and make sure it spins freely and doesn't squeak. Replace any defective pulleys as needed.
https://lh4.googleusercontent.com/-w.../WP_000128.jpg

As you can see, I really needed new belts.
https://lh5.googleusercontent.com/-l.../WP_000127.jpg

5.) route your new belts around the pulleys. Make sure you install the A/C belt first.
https://lh4.googleusercontent.com/-M.../WP_000130.jpg
https://lh6.googleusercontent.com/--.../WP_000131.jpg

6.) Tighten the tensioner bolt on larger PS/ALT belt using the 12mm socket with extension. You can use the feel method coupled with counting turns as I have suggested, or use a tension gauge and the FSM specs. Either way works. The first is easier, the second is more precise, so you can pick.
https://lh3.googleusercontent.com/-H.../WP_000116.jpg
https://lh4.googleusercontent.com/-1...belt+specs.jpg

After you get the belt properly tensioned, tighten the pulley bolt using the short 14mm socket. Double check the torque on the nut with a torque wrench: 30.4 - 39.2 N·m (3.1 - 4.0 kg-m, 23 - 28 ft-lb)
https://lh3.googleusercontent.com/-r.../WP_000135.jpg

8.) Tighten the tensioner bolt on smaller A/C belt using the 12mm socket with extension. Tension the belt properly using one of the methods described above.

After you get the belt properly tensioned, tighten the pulley bolt using the deep 14mm socket. Double check the torque on the nut with a torque wrench: 30.4 - 39.2 N·m (3.1 - 4.0 kg-m, 23 - 28 ft-lb)
https://lh4.googleusercontent.com/-G.../WP_000133.jpg

9.) Start the car and make sure everything is operating normally. If you hear squeaking, it's likely you did not tension the belts tight enough. The car should sound smooth with no squeaking or grinding noises. If everything is working as it should, reinstall the undershroud and you should be good to go.

good job

can this be done by yourself?

In a simple answer, yes. Should take you well less than an hour.

should I say life saver! lol thanks I will be doing this probably tomorrow or next week sometime.

Did this about a month ago and my car on cold starts squeals like a pig! Do i need to tighten both belts or just drive belt?

rthanks for this! Just what I was looking for as I threw the alternator/PS belt while pulling into a gas station this morning. Car is stranded there now. You think this would be possible to do from the top without jacking the car up and getting underneath? (this way I can fix it in the parking lot instead of having to get it home to my garage)

Possible? I guess anything is possible, but I don't see a real way to get to the tensioners from the top. If you had tiny hands/arms, it might be feasible. Even if you could get it from the top, it'd be a huge *** pain. You really need to remove the undershroud, and jacking the car up is the only real way to do that. You would be fine lifting only one side with the factory jack though, so maybe that would be an option for you.



Yes, it is most likely you didn't tighten your belts enough. If there's nothing leaking on the belts themselves, then they are squeeking because they are too loose.

You need to figure out which belt is squeaking. Try this:
At a stop while the car is idling, turn on A/C. Belt squeeks, probably A/C belt.

At a stop while the car is idling, turn on headlights, heat, and as many electrical accessories possible while turning the steering wheel back and forth (DON'T TURN ON THE A/C). Belt squeeks, probably the drive belt.

Yes, if they are new and not covered in oil, tighten them up a tad.
You can get to the bottom adjuster bolt through the top fairly easy if you feel around for a minute or two. Of course, lift is easier.

Update on my situation: Got a friend to tow me down the road to my house - I put the car in my garage and changed the belts in about 25 minutes. It helped that I've had a lot of practice removing and re-installing the underbelly panel.
My belts squeal like crazy now too. They already seem really tight though.

Thanks to OP for this great walk through. Used this to replace my belts this past weekend. No more chirping. The next day I went for a drive and heard a slight squeal when I cranked the engine...same thing today. My question is about how long should it take for new belts to stretch out? Is tightening the tensions again the only solution (meaning do I really have to take off all 600 undershroud screws again)?

Thanks!

I'm sure the belts do stretch some, but I think mostly what happens is the belts get glazed/dirty. When a new belt is installed, it is very clean and has good grip on the pulleys. After being on the car for just a little while, the belt surface accumulates dirt and such from the pulleys, which makes it slip some. This is why the belts didn't squeak at all when they were first installed, yet a day later they are already squeaking. If you were to spray on some belt dressing, they would probably be quiet again, as the dressing gives the belts more grip. I would never recommend using belt dressing though, and am using this as an example only.

The only real solution is to snug the belt up a bit more. Someone posted above that it is possible to adjust the pulleys from above without removing the undershroud, but I've personally never done it. You could also try and spray the pulleys and belts down with some mild soapy water, and let the car dry off overnight.

There's a button for that ===>https://g35driver.com/forums/images_...ost_thanks.gif

Thanks for your reply (also thanked your post btw). This morning was cold (18ish) and I didn't get the quick squeal like I have the past few days since the install. Instead it was delayed and a much longer squeal, close to 5 seconds and got louder each second, then went away.

Oh well, I can put it up with it a few more days and I'll just plan to tighten them both some more this weekend. As much as I hate removing the undershroud I love working under my car more.

Excellent walk thru. What would make this even better is to include a walk thru of the very simple idler pulley delete.

Only difference is the addition of a $3 part from Nissan (or free if you have a hacksaw handy).
And use the PS/Alt belt from a 2007 Coupe (07-08 FX35).

Hey i changed my serpentine belt drive and ac and after putting its start squaling but just after finish working seems like when the ac start running then its stops its always after work , never in the morning or night .. But the sound seems coming from the driver one .. Any idea what could be? Its not tight , not loose .. Where should tight more? The loose nut or the pulley adjust? Plz help thanks