How often should these be replaced?
We're talking about an LT-1 Mine happens to be a 95 in my FWB.
On many Mopars, these should be replaced around 60k miles, when the belt is replaced although nothing in the replacement schedule says to change them out with the belt.
The Allpar site, however, notes that the pulleys and idlers usually fail at around 80k or 90k. That's 20 or 30k after the belt change, unless you're really lucky, so I have to wonder about the belt in my FWB since something makes an intermittent noise at startup.
The noise stops after about 5 seconds when first starting in the morning and will not show up again for the rest of the day.
Since the overnight temp is near zero, however, the underhood noise is one helluva squawk now for about 10 seconds. That's actually less of a worry since cold weather - around 5 above zero - seems to make everything cranky. And as before, everything quiets down after that 10 seconds of squawling.
BTW - the serpentine belt has been checked and pronounced perfect by not only me but the dealer and the mechanic I trust, locally.

It is actually a weak part in the LT1 B and D body vehicles. It tends to get weak and cause squeaking, and not hold proper tension on the belt (slipping). COuld lead to accessory component problems (I think pow steering pump takes the brunt of the abuse). Most parts stores have replacements if you don't want to hold out for a GM replacement. I think it is in the $30 range, GM likely charges more.

Knock on wood mine have never needed replacement (yet).

I need to replace mine, I believe, as all is fine and quiet most of the time, but the first time it's wet or damp out, I get a terrible squeal after start up that eventually goes away as things dry off and heat up. Maybe this weekend, while I'm home, if it isn't too difficult and a local place has the right part.

That's what I figgered - and was afraid of.
I'll change out the idlers/tensioners as soon as possible.
Right now it's as cold as a mother-in-law's kiss outside so it will have to wait a bit. :suspense:

The last a while, I hate it when shops tell you to replace it because it has cracks in it. They almost all do within 10K miles.

I honestly personally have never seen one fail (serpentine). My 91 Bonneville went 270K on 2 belts, so they LAST. Watch the tensioner and when it starts get slacker, replace, or if chunks are missing, replace. There is usually some sort of indicator on the tensioner. see what is at.

Yup. As I said, the belt is fine. But what indications are there that the tensioners are going south?
>Is it that they are squealing like mine are on "first in the morning start-up?
or
>Is there some other indication?

Sounds normal to me. Most serpentine belts squeal with this cold weather while the car warms up. Check your belts for oil or other crap and get some no-squeal. Take a screwdriver to the side of your accessories, put your ear to the end of it, and listen for bad sounds. The thing you want to watch for if it doesn't stop after a few seconds. That's bad. Very bad.

I have an 88 RWD brougham, and I did the V-belts in October. It's setup with 4 circuts:

A: Crank, Water pump, AC.

B: Crank, Waterpump, Power Steering.

C: Crank, Airpump.

D: Waterpump, Alternator.

2 belts go around the crankcase and airpump. If one fails, it squeals. If a component fails, it squeals. Had to replace the water pump and power steering pump because they went. Alternator and Air pump are next (but those are easy).

If you install a brand new gatorback belt on the A circut and leave the B circut without a belt, you get rubberized coating all over everything as the belt shreds, then goes "pop" and you go "****". Then your coolant boils and your radiator finally pops a seam.

BTW, a nice feature of an iron engine is that it can get so hot that the oil pressure warning light comes on and you can crank it off and not blow anything. Did that twice. Funny to open up your hood and hear boiling.