To Replace or Not to Replace
 

Last weekend, I had to replace the starter in my 996. "While I was in there", I thought I'd also replace the alternator-starter-battery cable. In order to replace the cable, the alternator needs to come out.

When I got the alternator out, it sounded like the video below (ignore the video, just listen to the sound). The bearing isn't good, but its not really bad either. As you can see from the video, I had to get up pretty close to record the sound. I couldn't hear anything when it was in the car. I decided to replace it but a few friends have said that they would have left it.

Would you have replaced it or left it until it squealed like a banshee?

<iframe width="640" height="360" src="//www.youtube.com/embed/jgJJpSDK9mg?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>

After 23 years of flying military aircraft - I'm a big believer in preventive maintenance. If it's on it's way out, you might as well fix it now, before it strands you 50 miles from home on a Sunday afternoon.

Why take the chance?

Rick

If it was a Boxster I would definitely replace due to access difficulty. On 996 I might wait depending on several factors.

unrelated but I used to work on the flight line with F4 Phantom reconnaissance jets

I hadn't done the squeal test on mine before watching your video. It's not as bad as yours, but I'm replacing it with the non-squealer now. Old one goes on a shelf for 'emergencies'.
Edit: I just told my wife about this. She said, "It's a Porsche. No Squeal."

http://986forum.com/forums/uploads01/alts1415817418.jpg

25 years flying helicopters.

I voted yes, if you are in there, a part is suspect, I would replace it. I would do a little comparison, between how much trouble it would be to get back into that part vs how much it costs. If the part is very hard to get to, like the coolant expansion tank, then I might pre-emptively replace it if I had the transmission down to do an IMS replacement. Something like an ignition switch, I would replace at the first sign of trouble because I wouldn't want to get stranded. Something like a broken microswitch in the passenger side door that requires me to lower the window a little before letting folks in and out, I have been holding off for the last two years because it is not that big of an inconvenience...

Here is a related scenario - I am going to go in soon and install an underdrive pulley. Will I do WP and Thermostat when I go in there? I don't have any record of it ever being replaced, but I don't have any leaking coolant either. I will probably wait to do the UDP until I don't have anything coming up in the next few weeks and take a look at the WP, see if there is any evidence of seepage, or any play in the pulley, and if there is any sign of anything I will replace. If no sign of trouble I will probably wait for another day.