My wife's '91 740 started having problems this past week. She told me the brakes were going so I changed the front pads (the rear pads still look good.). I decide to drive it today to work just to make sure the pads get bedded in, well, there is a strange high-pitched, "thin"-sounding clicking coming from the engine bay. It gets louder and faster w/ the gas pedal and slows down and becomes almost inaudilbe at idle. I've yet to look under the hood, but wondering if anyone might have an idea.
I don't think it's loose valves, but I've only heard loose valves in other cars and on bikes, so maybe Volvo valves sound different.
She's going to make an appopintment to have it looked at, but wondering if I could look at anything. This car is my wife's only transportation for her 70mile daily commute, so we need to keep driving it...

Thanks for any help!!!
(There's also a leaking rear brake problem, but I'm still looking into that!)


Rolly