The heater/blower motor in my 78 Ford F250 had been screeching for quite some time. It started doing in the winter and once it ran about 5 minutes the screeching would quit. In the summer it was fine. I looked for a place to oil it but could not find any. It got progressively worse, taking longer to stop screeching and now even screeching in the summer.
I finally ordered a new replacement motor. It was delivered today and 2 /12 hours later it's installed (I know I work slow). After I was all done, thought maybe I should have bench tested it before installing. Got lucky it works on all three speeds and is very quiet running
I hope it last as long as the original.