Lexus LS400 HIGH PITCH NOISE when accelerating

[ls400newbie]

Hey, I just bought a 91 LS400 and when I accelerate it make a high pitch whistling sound. It is really loud, any ideas what it might be? It goes away when you take your foot of accelerator, it also does it in neutral when reving. I would like to have a good idea before taking it to a mechanic. Thanks in advance

 

[samsdad]

A/C on or off?

If it's doing it with the A/C off as you should when buying a new car get the timing kit and water pump replaced. A/C on then the compressor is the problem as pre-93 they do not like R134a refridgerant