How do I remove the thermostat from a 85 Vanagon

I just recently replaced a old radiator (small hairline crack near hose connections) only
to find that the expansion tank in the engine compartment is leaking. I've already
ordered a replacement which will hopefully be here tomorrow. It seems to be a simply
enough procedure, although I would also like to change the thermostat at the same
time to save time and coolant. Since I still have not received my repair manual for the
Vanagon, I'm not even sure where the thermostat is located. I'm aware, where ever it is
it had some kind of metal piece attached to it in some way. I've also read where the
bolts to this piece are prone to break off. I'd love to put some penetrating oil on these
bolts if I only knew where that are located!