frankv

So this morning while driving on the freeway various dash lights including battery light suddenly come on, I take a look under the lid and here is what i find. The alternator belt while it hasn't broke is fairly shredded and is lying loose in the engine bay, the alt belt teeth are separated from the belt and in 3 loose pieces, the fan belt is twisted inside out on the pulleys and has a gash ready to break and the ac belt has also twisted itself on the lower pulley. Nothing else seems to be wrong. Other than the dash lights there were no unusual noises and the engine was running just fine prior to shutting it off.

Before I change all the belts I am trying to figure what actually happened and whether either a failure with one of the belts led to the other belts being compromised or has something else failed that caused this carnage? I am thinking maybe the alternator belt failed and then got stuck between the other belts and the pulleys causing those belts to twist and this is also how the alt belt was able to get past the ac belt and get loose in the engine bay.. is that even possible??

I checked under the bottom pulley and I can see nothing there that may have caused a belt to fail. Fan belt sensor is fine. Fan is fine and can move by hand, fan bearing is new within the last year as is the alternator. Belts are of various ages, between 3-5 years old. I have not tried to restart the engine and haven't started taking anything apart just yet. Should I just change all the belts and call it a day?

Regards,

993-TJC

We're the belts OEM Porsche? I had problems with aftermarket belts slipping and breaking. They are a little narrower than the OEM brand.
Unless any of the pulleys run rough, new belts should fix the problem.
I would remove the rubber cover to the top of the cylinders and remove any debris that may have been sucked through the fan.

tsloeza

One thing you may want to consider taking a look at is the fan bearing. The bearing dragging/seizing up and causing the bearing and pulleys to heat up. Any blue coloring in the pulley halves. I have seen this before causing premature belt failure.

pp000830

Make sure you get all the shredded parts out of the fan blades if any
Has it been many miles since last belt refresh?
Once replaced and run for a while check the belt tensions.
Also see this TSB:

user 723923490

Another likely culprit is alternator bearings. Mine did the exact thing twice until I had the alt rebuilt.

PRSWILL

Alt bearing is a big culprit here. it should spin freely with NO sense of friction- even the slightest sense of friction or grinding means it's bad. If you can't spin it or the pulley stops after just a few rotations- it's bad. should easily spin for at least 30 seconds with a hard twist.

frankv

thanks everyone. The belts were Porsche but have close to 25k miles on them ... so it may be age related. The alternator was replaced last year as was the fan bearing so I am hoping that it is neither of those two, I will test when I have the new belts back on. The pulley halves look normal with no discoloration and I have done the pulley update as per the TSB. The fan looks fine so no damage there and it spins freely. I will take off the cover to make sure that no debris was sucked through.

I have new belts so I will put those on and see what happens; I am replacing all three so it gives me a new belt baseline.

Regards,