Replace the thermostat on a 99 malibu?

Answer

Should be located in a fremovable housing at the engine end of the upper radiator hose

Drain about 1 gallon of coolant from the radiator

Remove this housing

Note how thermostat is installed

Clean both surfaces

Replace thermostat and gasket

Replace housing

Re-fill coolant slowly to prevent an airlock

Start engine and look for leaks

Run engine to normal operating temperature with heater on

Re-check coolant level

Answer

Should be located in a removable housing at the engine end of the upper radiator hose

Drain about 1 gallon of coolant from the radiator

Remove this housing

Note how thermostat is installed

Clean both surfaces

Replace thermostat and gasket

Replace housing

Re-fill coolant slowly to prevent an air lock

Start engine and look for leaks

Run engine to normal operating temperature with heater on

Re-check coolant level

First answer by Baldfatguy. Last edit by Baldfatguy. Contributor trust: 1139 [recommend contributor]. Question popularity: 10 [recommend question]