Where is the thermostat located on a 1986 Nissan Stanza?

If you're talking about the Stanza Wagon with the EFI CA20E engine, the thermostat housing is on the left side of the engine as you're looking at it from the front. An easy way to locate it is to follow the main coolant hose from the top left side of the radiator back past the timing belt cover to where it attaches to the engine block. Where it attaches is kind of a curved metal housing with a wire attached, and two bolts. That's the thermostat housing. The wire is the temp sender that goes to the temp guage on your dash. Like I said, I have an 86 Stanza Wagon, but if you have the CA20E engine, it should all be the same. Actually, most engines are set up in pretty much the same way, with the hose from the radiator leading right to thermostat on the engine block. As soon as your engine heats up, the thermpostate opens and allows the coolant to circulate through the block and then back to the radiator. With a little detective work, you should be able to locate the themostat no problem.