When my car is idiling there is a it sounds like a clanking sound my cousin thinks it may be the water pump but we are not sure. He said it sounds like the fan blades may be broke off and bumping against something. But while driving it does not make that sound. It is a 1991
Check for a loose heat shield on the exhaust system somewhere. These can make a clanking/rattling sound when they become loose under certain engine operating conditions.
How many miles on the vehicle? If you don’t find a loose heat shield, then what you might be hearing is a stretched timing chain hitting the timing cover when the engine is idling.
Tester
It has about 114830 on odemoter