my 87 Runner w/ a 22RE is overheating, and boiling the coolant on shutdown. the fan is running, upper and lower hoses seem to be clear, but the upper hose isn't hot, which the Hanes manual says is indicative of a thermostat being stuck closed.

so I plan on replacing the thermostat, with a new gasket, and using RVT sealant. also, there are a bunch of vaccuum and other lines running across the top of the thermostat housing. is it going to create any problems to diconnect any of those to access the thermostat?

anything else I should be considering with the thermostat replacement, before trying to look at the water pump or radiator?