Where is the thermostat located on a 1991 Mazda MPV?

The thermostat is located underneath the front of the van on the driverside tire side of the vehicle. follow the radiator hose up to the thermostat housing. Note: the rubber o ring must be left in place if you are not planning to replace the thermostat, which, by the way costs like $35.00 and has to be ordered in advance.