Water pump problem?
 

What is typically the first signs of a water pump problem? My '72 makes extremely low rumbling noises when its running. Can't hear them when driving but only at idle. Not to say it isn't rumbling then too, just that I can't hear them over the normal road noise. It isn't constant.......will rumble for 15 seconds then stops or almost goes away.......then starts rumbling again.........but it almost always begins when stopped and idling. You can feel it too. Or maybe power steering pump? Doesn't seem to change when turning steering wheel though. Any ideas? Very annoying to say the least. Thanks everyone. By the way.......truck does not overheat....as a matter of fact, damn near doesn't move from the cold line ever. Haven't pulled 'stat yet. ?????????

Fan clutch, or the bearing on the ac pulley? Those noises can be fun to run down.......you might try pulling 1 belt at a time till you find the "offensive player". Good luck.....crazyL:bowtie:

Use a piece of heater hose or a really long screwdriver like a stethoscope. It will help you figure out where the noise is coming from. Yes, you put the metal end of the screwdriver against the pump, the plastic end against your ear, keeping your hands, ears and hair away from the fan.