Before replacing the thermostat, make sure you have a good 50/50 mix of coolant and have the radiator cap tested.
Poor coolant mix and a faulty radiator cap can cause overheating.
Drain cooling system below level of upper radiator hose.
Remove upper radiator hose, then the retaining bolts from thermostat housing.
Remove housing and thermostat as an assembly, discarding old gasket. Clean sealing surfaces with gasket scraper. Ensure not to gouge aluminum surfaces as these gouges may form leaks.
Install thermostat into housing, ensuring jiggle valve is up in relation to housing.
Position gasket onto housing using bolts as holding device, then install housing assembly and retaining bolts.
Install upper radiator hose.
Fill and bleed cooling system with recommended amount and mixture.
Start engine and inspect for leaks.