Well, more name that sound, but…. Our '92 240 with 121,000 miles on it recently started making this sound on start-up:
http://www.ravenandcrowstudio.com/Volvo/Car.m4a
I know I've heard other cars making that sound before, But I have no idea what it is.
It's usually only on start-up, sometimes very briefly, sometimes lasting a little longer and worsening on acceleration until you let off the gas, then it's gone until you power down the car and start it up again. The only exception seem to be when we run the AC it sometimes pops up too.
Any ideas?
Thanks as always.

 

sounds like an accessory belt noise - probably from one of the idler wheels. way to check is to remove the belt and turn the idlers by hand and see if there's play or friction. Also check the belt tension and wear. I'd suspect the accessory belt vs the timing belt as you noticed a change with the AC kicks on - which changes the load on the accessory belt - otherwise you'd also want to check the idlers on the timing belt. If you haven't done a timing belt in recent memory, it may be a good idea to do both at once... I don't think the 240s are interference engines but you still don't wait it to fail at a bad time leaving you stranded.

 

To me it sounds like a belt slipping or a bad bearing.

 

It's probably the belt from the a/c compressor. If you are standing in front of the engine, it's the one on the right side that goes straight up and down. <<Before>> you start the car, you can rub some soap on the inside of the belt to see if that makes the noise stop (temporarily). If so, then that is the one. If not, try it another belt.

 

240's don't have a serpentine accessory belt.

 

squeaky belt. Probably due to blown out accessory bushings=misaligned pulleys! Inspect.