Mazda 6 - Help me diagnose a problem
 

Hello,

I am owner of Mazda6 since March 2022. Its 2010 GH model, with 2.2 MZR-CD 95kW engine and currently at 251000km on clock.

Problem starter at end of December 2022, when my AC compressor died. After replacing AC compressor and micro-belt I have noticed a humming sound when its cold or wet (as presented in attachment), and once it was clicking sound after heavy rain.
Went to mechanic, he told me my belt tensioner is bad, so we replaced it and belt again. No more humming, car feels lighter to drive.
Parked it outside ( I don't have garage), it was raining all night. Tomorrow when I turned it on, I had clicking sound (as presented in attachment) for first 2 minutes after starting it.

I have sent video to my mechanic, he told me to come in 3 days, but have no idea what could make this sound since tensioner and belt are new.
Any help would be nice.
Thanks