WATER SPLASHING AROUND - most probably barado ang drainage ng evaporator mo. The evaporator is usually located in a big box behind the glove compartment. Kapag barado ang drain nito, maiipon ang tubig sa loob ng housing and you will hear water sloshing around. The drain usually leads to the outside of the vehicle kaya nga nagkakawater puddle sa ilalim if you leave the vehicle with the A/C running. Kuha ka alambre then tusukin mo yung drain pipe para maalis ang bara.

HISSING SOUND - it could mean nothing. It could also mean something's amiss with your expansion valve or your system is not fully filled with refridgerant. Isang taon na yatang ganyan ang tunog ng A/C ko. Hindi ko na pinapansin.

SQUEAKS - hindi kaya yung return spring lang ng pedal iyon? The one located under the dash and attached directly to the pedals.