I noticed a tapping sound 2 days ago. It has gotten progressively worse. It sounds like a metallic tapping and it seems like its coming from around the pulleys or the air conditioning compressor. The AC is working fine at this point. Any ideas what this might be???

 

So, what have you checked so far? I hope you are not continuing to drive it or you will have a major issue.

 

I don't know where to start. The pulleys seem to be tight. Would the AC compressor make that sound? This is an '01 disco II by the way.

 

If you are sure it is on the front of the engine, it will either be a failing oil pump, if not, you need to remove the belt and spin/check each belt driven pulley for a noise or roughness, including the water pump.

 

Ok. Turning the AC on makes it quiet.

 

You can take a yard stick, put flat side against your ear, and touch other end to various spots. Sound travels very well thru a solid, and you will hear it in more detail. Be sure to listen to valve covers in several spots. Alternator. pumps, AC compressor, etc.