Extreme cold weather can harden and split the seal between the engine
block and the oil cooler thus creating an oil leak:
*  An improved cold-restistant seal was installed in production as of
   02/87.
*  The new seal can be identified by its silver-grey appearance and is
   available through your parts department, Part No. N 901 814.02.

so everybody who lives in the Frozen Frontier might want to get this checked
... i do NOT know if the vw dealers will do this free or not, but it might
be worth a shot.

also check the tightness of the nut on that oil cooler when you next change
the filter: it may loosen, and let the oil cooler move around a bit when the
filter is removed. if so, it might not line up correctly on the gasket if
you don't take care installing the new filter.

joel