Blower Motor Sounds Like On Board Air

[PAFirefighter11]

Hey all. My blower motor is goes back and forth from quiet to VERY loud, like an On Board Air (OBA) system. I took the motor out and ran it removed from the compartment. It spins great and makes no noise. I reinstall it and it goes back to making noise. Do I need to replace the motor itself or is this noise the circular white fan piece that sits on top?

Thanks...

 

[RonJ]

After you remove the blower motor, reach your hand into the hole to search for any loose debris.

 

[sleeper si]

sorry to resurrect an old thread but my motor is hard to spin almost seized. can i open it up and replace the seized parts?