zenithblue993

Well, after a couple days I finished installing a new alternator, and alternator fan. Belts were 5 months old.

I am getting this noise now, pretty sad.

and


I dont think it's the fan hitting the black housing cause from the second video it looks perfect. I could be wrong. I also took the chance and installed the pulley update.

Some thoughts:
1. Does the spacer sleeve that goes on the alternator shaft first and then the fan. Can that be out on backwards? It looked like a solid cylinder.

Ill probabaly remove the first pulley(updated) and put the old one back on and see.

Any ideas?

Jwolf427

Sounds like the belt is to tight, causing the fins to rub against the fan housing.

zenithblue993

Ya I thought I did it tight. But I read the main 24mm nut on the end is suppose to be 50nm. At first I had it at 50FT LB. Then i realized it was in nm. So I loosen it to 37ft lb(which is what I think the torque is suppose to be).

How tight should the 5mm 3 screws holding the big pulley be?

michel j

Maybe your bearing is bad. Mine howled for a while after the last belt change. The noise stopped after a day and that was two years ago (4K miles)

zenithblue993

Hmm. I should just go drive it hard lol. Maybe it will go away.

But I don't think so, everything is new except the old fan pulleys and shims.

TMc993

The shims placed between the pully halves are the primary determinant of belt tension. You may find this to be helpful: http://p-car.com/diy/vbelt/belts.html

zenithblue993

So I removed 1 or 2 shims from the fan pulley and 2 from the alternator pulley. And well sparks flew. The fan was hitting the bottom and you could see tiny sparks...

Vandit

If you're running new belts, you need to be running max shims, which is 6 per pulley.

OverBoosted28

^^^^^as he stated, new belts have their full (un-worn) width. You need more shims, not less. Not sure if it's just the vid quality, but it looks like your fan isn't spinning at a constant speed. If so, it's the hub bearing. Check play when you pull it back apart (alt. shaft). If it's this bearing, sorry.

zenithblue993

The first video looks like it's slowing down. But that's just the video quality. It's spinning constantly.

I had my old belts on when doing all the test that have been broken into already.

Just to confirm, the only thing behind the fan when I put it on the alternator shaft is that round sleeve right?


And also so there's nothing connecting the fan to the alternator right ? Like in the picture I can move the fan back and forth while connected to belt.

Just some things im trying to rule out.

kjr914

Correct. In order: alternator-->spacer-->fanbearing
My spacer was symmetrical.

Question: Did fan spin freely when alternator was mounted in the housing? It should. I found that a rebuilt alt I got had a slightly different front housing, that caused it to drag. I took that one back and got another. I'm not sure if there are 2 spacer sizes or I got an alt from an older car???

More shims = less tension.
Less shims = more tension.
You increased the tension on the belts and pulled the fan down into the housing. The fix: remove shims, repeat experiment.

Basically, you need to Goldilocks that sh*t....not to tight, not too loose, get it juuuuusst right....

Question: Did you tighten up well the 4 bolts holding the alternator into the fan shroud? If the alt is loose, it could move.

One way to get them all adjusted:
1. Remove AC & alt belt, leaving ONLY the fan belt. (Remove EVERYTHING from the engine compartment where you were working....belts, rags, tools...your fan would love to suck in a rag, your belts will not love this rag....) Start car. (You will get the alternator warning light...its ok.) Is fan hitting the housing? If it is, add shims to reduce tension, and repeat the experiment. You can also use the Krikit belt device to measure tension.

2. Now repeat #2 with the alternator belt. (You will not get the alternator light now.)

3. add AC belt, and drive.

I have always re-used the same # of shims that was on there before (and the same Porsche OE belts). If you don't know what tension you need, start with more shims and reduce as needed as Vandit suggests.

Yes, only the spacer behind the fan bearing.

The fan and alt spin at different speeds, thus the two belts. So with the first belt on (fan belt), you can spin the alternator shaft independently. The fan should be locked in place by the fan belt if correctly tensioned.

Your comment says "I can move the fan back and forth"...if the fan belt is on, it should not move.

zenithblue993

Thanks for all the info! And i check the 4 bolts and 1 was loose! So I tightened it.

Is there 4 washers to go with the 4 nuts? I dont think I put them on if so. Not sure if I lost them or they weren't there in the first place.

Anyways then, I did like you said. Put the pully, shims, "old" belt, other pully. Then put in the 3 5mm bolts. And turned on the car. There was no noise!!

So then I put the alterntor pulley on with shims, pulleys and the belt. Then the 24mm nut. Tightened it to torque. Then turned on the car it made the metal noise again......

Took off the alternator belt/ pulley turned on the car and the metal noise was back (Where is wan't earlier). I don't know if there is a sweet spot where the fan rides on the shaft or what..

zenithblue993

SOLUTION: Make sure all 4 nuts are tight equally and remember to put the 4 washers back. Without them, the alternator will move around slightly hitting the housing.

My car is up and running again!

EMBPilot

YOUR BELTS ARE TOO TIGHT

OverBoosted28

Well it sounds as though you found it. For the most part, (as others have said) the belts need to be barely tight enough not the slip. Much better to be to loose than too tight (alt. bearings).