My 04 Disco just developed a strange tick/rattle that sounds like it's coming from the AC compressor or very nearby. At first I thought it was the fan clutch because it seemed like it has a small amount of play in it if I grabbed opposite sides of the fan and wiggled. Just replaced that and it wasn't it. It's not a constant rattle, and sometimes it varies slightly when I have the AC on or off. The AC clutch engages when on and doesn't when off. Almost sounds like the marbles in a couple of spray cans rattling around.

Hard to tell for sure if it's something inside of the AC compressor or the idler pulley right below it. Maybe something else? I could take the belt off and run the engine without accessories to see if that eliminates it, but it won't tell me which accessory or pulley is the issue.

 

I was going to suggest pulling the belt to determine if it's the engine or an ancillary. You won't hurt anything for 10-15 seconds, which should be plenty of time. Assuming it is something belt-driven, get a long screwdriver to use as a stethoscope on the various rotating components.

 

Well, didn't take long to figure out the issue after removing the belt. Spun accessory pulley's by hand and found my power steering pump pulley loose. I replaced the pump a few weeks ago and one of the bolts stripped a little and backed out. Fixed for now. If it doesn't hold, I may just replace all three bolts with slightly longer ones that I can put on from behind and lock nut on the front of the pulley.

Now on to recovering the door insert fabric. Not my favorite thing to do.