Thats the A/C Compressor, but nothing is wrong with it. Its just cycleing on and off more often because you are low on R-134a. Go and get the A/C systrem charged, problem will dissappear.
98 Corolla LE 1.8L DOHC 1ZZFE
TEIN H.Tech Springs
Tokico HP series Struts
Short ram air intake
Tsudo Axel Back Exhaust
... if a jelly fish stung me.. would you pee on the wound?