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Question:

Is there normally a way to grease the bearings in the main motor on an AC?

The motor I'm talking about is the main large motor in the very bottom of the unit. The unit (which is in the basement) started making a loud humming/squeaky sound. I automatically knew it was probably bearings. I took off the lower panel after I shut it off and reached back there and turned the pulley and it is squeaky yet turns pretty easy. We sprayed some WD-40 on the center and turned it back on and there is no noise now.Is there a way to use a grease gun to grease the bearings normally? If so where would I look for it? Any other suggestions are very welcome!

Answer:

LOL contactor?..women (shaking head). Sounds like this is your indoor blower motor. If its on the pulley you could grease in the center where it connects to the shaft. Other than that use wd40 like you did. If the bearings bad you're gonna have to get a new blower motor eventually. I say this because they don't sell the pulley/bearing seperate from the motor. Few hundred $ installed by ac tech. Only other thing it could be is where the motor mounts up. Could be vibrating. Wd40 would help or it may have vibrated loose over time needs to be tightened down. Sounds like the blower motor pulley from what you explained...
Some motors have sealed ball bearings - no lubrication required. Others use common light duty oil. If yours is sealed, you won't have anyway of injecting oil or grease. If you have sleeve bearings, there will be an opening on the end of each motor bell housing where you can inject oil. It may be covered with a plastic cap (mine was a plastic yellow cap/plug about 3/16 dia). The WD-40 is a temporary fix. It will squeak again.
Get a tube of lithum grease and just pop off the black end cap and use your finger to pack the bearings. Or look for a zute near the bearing housing. Zutes are for grease guns and looks like a clit with a bearing in the middle.
Make sure the filter is NEW and clean. The motor works too hard if it's sucking air through a dirty filter. The electrical contactor inside may need to be replaced (you need a qualified HVAC tech or electrician to do this).

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