Auto AC compressor diagnoses.
 

My 2001 Ford F150 with 216k on the clock now has a ticking coming from the AC compressor. Not sure if it internal or the clutch. The AC is on its original charge and it still blows cold.

Any ideas on what might be making the ticking sound? Should I try charging it up? Or just replace it.

It's my daily driver and I can't live without the AC.

Does the noise change with the A/C on vs off?

The drive belt?

Leave the charge alone. This truck has a FS10 Compressor, it's most likely the clutch. You can tell by the discoloration of the body of the clutch assembly and compressor body. If it's redish brown, you can do one of two things. Replace the clutch assembly, or remove one of the two shims which set the air gap to get more life out of the clutch. 8 or 10mm socket to remove the friction plate which hides the shims.

The air gap should be about the width of a business card. I'm guessing you could jam a few in there.

The noise stops when I turn the AC off.

The drive belt is relatively new. The noise stops when I turn off the AC.

You make it sound easy! Any place to learn how to to do it?

I'll take a look tomorrow.

You could try here. They have always helped me out. Several good techs.

Automotive AC Information Forum - ACKITS.COM

If the noise goes away with the A/C off, that isolates it to the compressor and/or compressor clutch. Matt's suggestion definitely seems worth trying before you replace it.