I have a 1992 740 volvo wagon and when it starts there is a noise coming from the front of the car only when it is idling. When it is in park and I switch it to reverse is the only time I can hear the noise. Any ideas on what could be causing this would be greatly appreciated. Thanks

 

Could be a heat shield on the exhaust but usually you will hear them rattle at certain speeds while driving as well.

On my wifes 240, the water pump made some rattling noise only at idle. Check it for play by wiggling the fan (engine off of course). You may need to loosen the belts to be sure.