Help.

My 10 year old Tempstar Model N8MPM075B12A1 furnace suddenly makes a high-pitched freight train noise whenever it is running.

Any thoughts on a DIY fix? I am pretty handy at replacing parts, etc.

Thanks in advance for help.

Check the blower. It sounds like you either need to oil the motor or replace it. Most of the time when it's making noise the bearings are ruined from lack of oil. Even if you oil it the bearings will fail quickly. If you need a new motor just make sure to get the rotation correct. The blower rotates the direction the fins are pointing on top, outside edge. You can go up on horsepower, but not down. You can replace a 1/4 HP motor with a 1/3 HP and it will last longer, but can use more power, not always with high-efficiency motors which are good to use. You have three-speed motors, but use only two. High and medium or low. The high is for AC and low or medium for heat. NEVER short two speed wires together or it will instantly burn up motor. I would cut wires on old motor to see how to wire up new one. One speed wire will be taped to keep it from shorting. Many motors are also reversible, so you will have to see which way it turns. Motors are marked CCW or CW from shaft or lead end. It should be an easy job, but pulling blower off can be hard. You may need a puller.

Thank you so much. I really appreciate your information. I will work on that. Take care.