If I may answer my own question I went to a couple of wrecking yards today
and looked at a few heater fans. No two had the same part number. So I'm
guessing most Vanagons have the same heater blower fan with inconsequential
differences that warrant different numbers. In looking at those fans I also realized
they are a fair amount of work to get to. That combined with the possibility of
an old motor having or about to have the same bearing problem my motor has
gave me the resolve to decide to go for a new fan for in the $100 range rahter
than monkey with a used motor.

Thanks for listening
Jeff
83.5 Westy
LA,CA

In a message dated 10/25/2003 3:11:17 PM EST, Oxroad@AOL.COM writes:

<< I got a heater blower fan for the front heater from an 88 Vanagon in a
 wrecking yard. The heater unit shell was not split and so it would seem had
the
 original factory heater motor in the shell. I split the shell and took out
the
 electric fan with the part number 321 819 021 A.  printed on it. A
manufacture
 date of 88 was stamped in the side. The Vanagon seemed to be all stock and
 certanly not modified in the heater shell area.

 I see ETKA lists the heater fan motor for 83-91 Vanagons as 251 819 015  the
 Bus Depot lists the same fan as 321 819 015. >>