Changing thermostat, '89 A100?

["P-O Selander (EUS)" <EUSPOS@am1.ericsson.se>]

Elliot wrote about his experiences of the AllData CD for the Audis. I
had contemplated buying it (pretty inexpensive), but after seeing
several negative posts, I think I'll put it off.
However, quoted a procedure to change the thermostat and that included
removing the timing belt?!

I changed my radiator in early January (hose fitting for breather hose
broke) and in order to do this I had to remove the hydraulic pump. Once
the pump was gone, the thermostat was pretty accessible. Unfortunately,
I did NOT change it at that time (don't ask me why) but will have to do
it soon.
Therefore my question; What is the proper procedure to replace the
thermostat on 1989 100E with I-5 engine?

And, I was looking in joining the AudiFest this weekend, but decided on
going to Santiago, Chile, instead since airfare was cheap and that might
be somewhat more of an adventure (even though driving up to Colorado
Springs in the traffic around the 4th can certainly be challenge). So,
have fun up in CS, love to be there but the cool weather in Chile was
more tempting this time...

TIA /// P-O Selander, Dallas, TX
89 100E
91 300ZXTT (for sale)