T300 Cooling Fan Issue

[Zaylor11236455]

Need some help. I am going to try and provide as much info as possible.

My machine is a 2008 Bobcat T300. Serial# A5GU20413.

This summer I had the hydrostatic and gear pump rebuilt at around 5,600 hours. When I got my machine back from the shop it was overheating quickly. I ended up finding that the inlet and outlet hose on the fan motor were switched around not allowing the fan to run at all. After I switched them back the fan would only run on high. I knew it was only running on high because when I first switched the hoses back I pulled the pressure sensor to make sure the fan was working.

Since then I have probably put 20-30 hours on the machine not worrying about the fan motor running on high. Today I was plowing the driveway and it began overheating again. The fan is turning but very very slowly.

I lifted the cab cab and pulled the pressure switch and nothing happened.
I cracked open inlet side and was getting hyd fluid.
I cracked open the outlet side and was getting hyd fluid.
I then unplugged the coil and nothing happen but I did code M3507. Which made sense.

My questions
What would cause the fan to only run on high?
Would the fan running on high only burn the motor up?
Did replacing the hoses backwards do damage?

 

[crewchief888]

my best guess is that the fan control spool is stuck. if you unplug the coil connector while the engine is running the fan should go to hi speed, if it doesnt, the spool itself should be replaced.