Don't know about the '90, but I just did this on my '87 2.1L.  It was a
pretty simple job.  If you haven't already, you might want to get a new
seal while you're at it.

Darren
'87 Westy

-----Original Message-----
I  am about to attempt a themostat replacement on my '90 2.1L. In doing
some research it sounds like it is sorta tricky (but I think this was in
reference to a 1.9L engine). Apparently there were some issues with
getting the thermo. housing disassmebled(??).