Reasons for WATER LEAKAGE FROM AIR BOX DRAIN PIPE in HHP locos

WATER LEAKAGE FROM AIR BOX DRAIN PIPE 
a) DEFECTIVE WATER INLET TUBE. 
b) AFTER COOLER TUBE LEAKAGE. 
c) HEAD TO LINER GASKET & JOINT LEAKAGE. 
d) DAMAGED POWER ASSEMBLY. 
e) IMPROPER FITMENT OF WATER INLET TUBE.