Chirping noise coming from engine

My 05 Tacoma just reached the 250,000 mile mark and she just recently started making a chirping noise. I had my belts checked yesterday with an oil change and they said they looked fine but I was leaking a small amount of oil from somewhere as a bit of it had collected on some hoses. I check my oil level most weekends and don't notice the level dropping.

My question is how much of a concern is this minor oil leak and what can I do to make this chirping noise go away?

 

An easy thing to do is to remove the belt, then start up the engine. You can safely run it this way for a few minutes when cold. If the chirp is gone, then it’s one of your spinning bits that probably has a bad bearing. Go through and check all the idler pulleys and the tension pulley, alt, A/C, water pump, power steering. If you’ve never replaced them, I’ll bet the idlers and tension pulley are all in need of replacement. All but one on my ‘11 needed it at 112K.