I think I discovered the squealing noise on my 944

"K-Roll-PorscheTamer" (k-roll390)
12/17/2014 at 20:24 • Filed to: 944 Lyfe

I think it's this belt or pulley, right here! I sprayed WD-40 on it and the squeal went away for a short while then came back. What is that, the alternator/AC? In fact, what does a belt do for the alternator anyway? Ima gonna have to change it and the pulley I'm guessing, not sure which one is causing the squeal.

Or maybe I can spray it with something?

DISCUSSION (28)

Funktheduck > K-Roll-PorscheTamer
12/17/2014 at 20:30

There's stuff called belt conditioner you can use but that belt probably needs replacing. That belt, if connected to the alternator, keeps the alternator operating and thus, your car.

The pulley comes attached to the alternator. If the pulley is the source of the squeal you'll have to replace the whole thing because the bearings would be starting to wear out. It's generally a cheap fix.

K-Roll-PorscheTamer > Funktheduck
12/17/2014 at 20:35

I learned something new yay! I'm gonna go by some car shop and buy this belt conditioner stuff and see if the squeal goes away. If it doesn't, then it's the bearings and I'll replace both either way.

Would my car die if the belt snapped? What exactly would happen?

TheD0k_2many toys 2little time > K-Roll-PorscheTamer
12/17/2014 at 20:36

The belt spins the alternator and the spinning in the alternator creates the electricity that your car uses to run. If its the pulley itself squeaking then it needs to be replaced. Do the belt change first because usually its just the belt wore out

Zipppy, Mazdurp builder, Probeski owner and former ricerboy > K-Roll-PorscheTamer
12/17/2014 at 20:38

it would run on the battery until it dies I think, it depends on the system.

Phyrxes once again has a wagon! > K-Roll-PorscheTamer
12/17/2014 at 20:38

If that belt snaps the only source of electrical power in your car is now the battery, which is not going to be able to keep everything running for very long.

cbell04 > K-Roll-PorscheTamer
12/17/2014 at 20:39

Since there is no idler on that set up the alternator likely rocks a small amount to create belt pressure. That metal rod the arrow is pointing to is what is creating the tension. You should be able to adjust it and add some tension to get the squeal to go away. Haven't worked on 944's but %99 sure that all you'll need for now worth a try.

cbell04 > cbell04
12/17/2014 at 20:41

To further explain you would be basically turning a screw attached to a long bar that would push the alternator away from the engine causing more belt pressure.

K-Roll-PorscheTamer > TheD0k_2many toys 2little time
12/17/2014 at 20:41

Adding to the list of tune-up things I have to do this winter. I'm wondering how I even access the belt and do the work. Lifting perhaps?

cbell04 > cbell04
12/17/2014 at 20:42

found this http://forums.pelicanparts.com/porsche-924-94…

JGrabowMSt > K-Roll-PorscheTamer
12/17/2014 at 20:42

Small pulley on the accessory makes me think alternator. If the alternator is making noise, replace it. This should be something you can do, but there's something to keep in mind with this:

There's no tensioner on that belt. Because there's no tensioner, it means you need to make sure that the accessory is in the correct position and the belt is tight enough to actually run the accessory, otherwise it just wont work. In the case of an alternator, that's a big problem, because it charges your battery. Something we'd call a "big deal." Also, the AC compressor will only make noise when the AC is turned on (assuming there's something wrong with the unit).

So with that in mind, you'd want to replace the belt when you do the accessory anyway, just as a safety, but the belt doesn't typically make noise unless it's slipping (which is possible, but not all that common in my experience), which would be caused by too little tension or belt stretch, which would be normal if it were a pretty old belt. I would ask the shop that did the timing belt it was was changed or recommended to be changed.

From that picture you posted, the larger pulley from that loop is the crank pulley. If this is making noise, you've got a massive problem. As long as it's just the accessory, you're fine.

Tinfoil Hat in a thunderstorm, now with added diecast > JGrabowMSt
12/17/2014 at 20:44

The alternator pivots from one end giving the tension, no idler pulley required.

K-Roll-PorscheTamer > cbell04
12/17/2014 at 20:47

I was actually just pointing to the entire assembly in general, but I'm not sure what the rod is for. I need to raise the front somehow to do this. If the belt is already worn or the pulley, then they'll need replacing. This would be the most car maintenance intensive thing I've ever done.

K-Roll-PorscheTamer > Phyrxes once again has a wagon!
12/17/2014 at 20:47

That doesn't sound so bad since it's on battery tender in the garage right now.

K-Roll-PorscheTamer > Zipppy, Mazdurp builder, Probeski owner and former ricerboy
12/17/2014 at 20:47

Hmm. Better change it then.

JGrabowMSt > Tinfoil Hat in a thunderstorm, now with added diecast
12/17/2014 at 20:48

Yes, it needs to be adjusted correctly as I included in my ramble.

K-Roll-PorscheTamer > JGrabowMSt
12/17/2014 at 20:50

If I go start it up now, I can kinda fingure out exactly which pulley/belt area the noise is coming from and that should help some. What noise should the compressor make when the AC is on? A large fan comes on when I turn the AC knob.

I imagine I should change it like the rest though.

Tinfoil Hat in a thunderstorm, now with added diecast > JGrabowMSt
12/17/2014 at 20:52

I was referring to the "There's no tensioner on that belt." Just wanted to alleviate confusion as it has a tensioner just no idler pulley.

TheD0k_2many toys 2little time > K-Roll-PorscheTamer
12/17/2014 at 20:55

From the location id say it would be easiest from under the car. Unless there is a lot of space under the hood in front of the engine

JGrabowMSt > K-Roll-PorscheTamer
12/17/2014 at 21:00

The compressor shouldn't really make any noise when it's on to be honest. When the AC turns on, it likely causes a fan to come on to prevent overheating, but also to cool down the refrigerant in the condenser. Just a safety feature really. If you turn on the AC and you get cold air in a reasonable amount of time with no squealing noises, your AC compressor is probably just fine.

Kinja'd!!!

This is a bottom up view of a 944. AC Compressor is on the left side of the image, the alternator is on the right side. You can also see the tension arms for both accessories, which is how they pivot and then get the correct amount of tension on the belt. Looks like a bottom up approach is the way to do an alternator job on this car, you just have to work around the steering rack and sway bar, but it looks like you have plenty of room to do it.

K-Roll-PorscheTamer > JGrabowMSt
12/17/2014 at 21:07

AC is working great then. Do I have to tension anything when doing this change? How do I do that?

Funktheduck > K-Roll-PorscheTamer
12/17/2014 at 21:50

So there's an fun test you can do (but shouldn't on newer cars). Start the car, while it runs disconnect the battery. If the car dies you're alternator is dead/dying. It can screw up electrical systems on newer cars so you probably shouldn't try it. It's the redneck way of testing.

If the belt snaps/alternator dies your car will somewhat quickly die while driving. The battery won't last long powering the car (sparks for spark plugs primarily) and that could be dangerous depending on the situation.

The belt conditioner is a temporary fix. You really should replace the belt at least.

2BWise > JGrabowMSt
12/18/2014 at 09:11

left side is the power steering pump. AC compressor should be above the alternator. Although I've been without a 944 for two years and I may have subconsciously removed all memories of maintaining it.

Stef Schrader > K-Roll-PorscheTamer
12/20/2014 at 02:19

HA. We kept losing that belt. Yep, it's the alternator.

Stef Schrader > Zipppy, Mazdurp builder, Probeski owner and former ricerboy
12/20/2014 at 02:46

That's exactly what happens when that belt snaps. It's not catastrophic, but nothing will charge your battery. It'll run 'til your battery dies. You'll get less and less spark, which means it'll rev less and less until you limp back into the pits with only 2K max in revs.

Source: Going out on track for about 2 hours and 20 minutes with no alternator. Haha.

K-Roll-PorscheTamer > Stef Schrader
12/20/2014 at 02:59

I bought some belt conditioner and tried it out on the belt. Unless I used it incorrectly(sprayed directly on moving belt while car running) it didn't get better. Im just going to have to fix it in the spring. I hope it can get me to Ohio before breaking! (0_0)

How lomg did your belts last?

Stef Schrader > K-Roll-PorscheTamer
12/21/2014 at 04:11

I think the change interval is around 30K or so? It's pretty short.

K-Roll-PorscheTamer > Stef Schrader
12/21/2014 at 12:10

So I just need to replace the entire alternator then?

Stef Schrader > K-Roll-PorscheTamer
12/22/2014 at 08:36

Possibly.