Engine chirping noise

The first time I heard the chirp was imeadiatley after I had the oil changed, I spoke to the tech about it and he thought it could be belt and coincidental to start then. I took it to a mechanic to check the belt and tensioner. He took the belt off and I still have a chirp, he thought it could be comming from the bottom of the engine, and said it could be an inferior oil filter. Jiffy lube said the filter was tight and a quality filter. The engine is running fine with no smoke or loss of power, just a never ending chirp.
Thank you!