If the blower is squealing the only real culprit is the motor bearings. If you stopped it as soon as it started squealing you can very likely save it just with some oil dribbled on the bearings (use Zoom oil for best results). If you've been running it with it squealing anyway, the bearings are ruined by this point and you'll need a motor.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]