Whining noise

Okay, I'm hearing a whine from what seems to be the passenger side of the
engine...sounds a little like a siren as I accelerate / decelerate. Not a
squeal or squeak.

156,000 miles on a '94 SL2. I'm guessing it's a tensioner or
alternator...not ruling out power steering. (I'm afraid to stick a
stethoscope on any of those that close to a turning serpentine belt!)

I can replace all three components myself for a reasonable cost. They're
all three original equipt, so it might not be a bad idea anyway. My wife
had a '93 and we replaced the alternator AND the tensioner, but that was due
to bearing failure, not just a whining noise.

But can someone help me rule out a noisy timing chain? What do these things
sound like when they get old? It occurred to me last night that the noise
might be the chain rubbing on the chain guide.

This noise has been around for about 20,000 miles, or two years, and I was
just waiting for something to break. Now I'm not sure it'll ever break!

Any help?

Thanks

 

I had this same problem shortly before my alternator went. This was on a 92
SL2.

 

My 2000 SL1 had a very irratating whining noise from the passenger side. It
got worse whenever I drove past malls. I broke up with my GF and the noise
stopped.