Air Conditioning - sounds like fan on outside unit making noise

Thanks for this website forum. I live in Houston where temperatures are now in the triple digits. I own a home with central air conditioning, the unit is a 1989 Trane but runs great for its age. Last year while the ac was on during night time, I heard a chaffing, low and high tone squeak from the outside unit, so I took my flashlight and went outside and did not see anything out of norm. I sprayed a little WD40 around the blade shaft, that seemed to stop the squeak. A year later, today, it made the same noise again and I sprayed a little lubricant around the fan shaft; that stopped the noise. Is this normal because of age of unit or is there a better way to stop this loud squeak , I am worried that something could be damaged. Thank you.

If is squealing the bearings are probably damaged. It would probably be best to replace the motor before it siezes.

Thank you for that suggestion. If I asked an ac repairman to come check it out, what would I tell him? I know that the ac will be purring like a kitten when he comes by, that's the way it usually seems to work. He'll hear nothing and probably say for its' age it is doing fine, I respect a professonals' advice but what specifcally would I ask. I think when you said motor you mean fan motor, are they expensive? Thanks.

Probably $60 for the motor, maybe another $20 for the associated capacitors (always replace caps when you replace motor). Unfortunately, you will pay the markup if you have a Tech do it...so figure $150 or so for the parts plus the cost of a service call.

If you have even the basic skills required, the Pro's here could help you do it. Have you ever replaced an outlet or light switch? Changed your own oil? If so, you can do it...

Thanks gg45, appreciate that information.