4K radiator fan replacement questions

[nicholls@mikey.convex.com (Sam Nicholls)]

Hi Folks,

The radiator fan/motor on my '86 4000S (1.8L) is toast.  It's completely
stuck.  I think the bearings must have worn out or something.  What is
the cheapest way to replace it?

The local Audi dealership wants $195 for a new one.  A local shop
wants $175.  A local junkyard has one for a 5000 for $50.

Do the 5000s use the same fan/motor as 4000s?
Can I get the same part for a VW for less $$$?

As usual, many thanks,
Sam Nicholls <nicholls@rsn.hp.com>
'86 4000S (1.8)