Well, I have been fixing things on the new to me 1980 450sl. The blowerwasn't working at all, and I pulled it out today. It was seized tight, so I put some PB Plaster on it and got it freed up, but it doesn't spin very easyand when I tried it, it wouldn't work.
Keep at it with the lubing. Make sure that it draws current, I use a battery charger to spin them while I work on them. If it's burned out you'll probably need another. -- Jim