Bruce Kaiser

One of my fan belts broke while on the highway the other day. On inspection the other belt was very loose which was allowing the fan to turn freely. How would one belt breaking cause the other belt to lose tension?
Both of these belts are less than 1 year old? Is it normal for them to break? What may have caused it.
It also appears there is a crack in the fan itself. Could this have caused it? I did a quick search on Pelican for a replacement fan but no luck. Any ideas?

Now for the stupid question. There are three belts running off the engine. One is the a/c. The other two run up to the pully assy on the alternator and fan. Do these two operate independantly of each other? ie does one turn only the fan and the other turn the alternator? I had it in my mind they were redundant belts providing backup to each other.

jimq

the alt and fan turn at different speeds hence the 2 belts.

JasonAndreas

If the belts aren't tensioned properly it's possible, I've also heard of problems with aftermarket belts and mechanics using the wrong size.

Is the crack just in the fan blade or the outer housing? The replacement blade for MY92+ is part #964-106-015-31 with an MSRP of $418.37 so plan on spending ~$200USD. PET is showing the fan blade for MY89-91 as part #964-105-015-02 (MSRP $159.02USD) but that part has been dropped so it might not be available? In which case you might have to order the MY92+ blade and new pulleys, etc.

Bruce Kaiser

The crack is in the blade. not the housing.
So the diagnosis is in. The pulley failed and took out the belt.
The service desk at the dealer suggests that to repair this the alternator has to be replaced as well because the fan, alternator and pulley are integral.
I've seen several discussions on replacing the alternator that don't seem to suggest this is all one assy.

Bill Gregory

The fan, as noted above, is available as a separate component (I replaced mine years ago without replacing the alternator), as is the pulley. Refer your dealer to illustration 105-00 under 964 in the Porsche parts catalog (PET). Should look like the attached.

SNOWBIRD

Bruce, Should it apply to you; The belts are different numbers (size) on the Tiptronic cars.

Bruce Kaiser

Turns out the impeller hub and /or pulley sleave failed, taking out the belt and cracking the pully. I replaced the fan as well since it had a couple of cracks in it and I seem to have too much money.
Back on the road. Thanks for the help.