Hello Everyone, I am trying to help out a friend with this problem but am having a hard time, Its a Blue Bird AA RE with a Cummins C-Series and he replace the Hydraulic Fan drive due to it leaking and when he replaced it, the new motor blew out as soon as the engine was turned on. Anyone have any suggestions or experiences with this
i heard that back in the day this was a problem. the fan motors had in/out ports only. the fix was a third port on the motor to return excess pressure back to the reservoir. also, there should be a solenoid valve somewhere that controls pressure to the fan that usually fails in the default (open) position. if the fan is running full all the time it can blow out prematurely. though there is always the chance that your friend got a defective one.