Where is the thermostat located in a 1999 chevy truck?

Follow the top rad hose to your intake manifold, where the rad hose is connected on the intake manifold is called your thermostat housing. Drain your coolant level some (preferably while the engine is cool to avoid burns) then disconnect the rad hose from the housing. Next undo the two bolts holding the housing to the manifold and gently remove the housing with the use of a small scraper. Once the housing is removed you'll find the thermostat. Simply lift the thermostat out of it's place, clean off and remaining gasket material from the base of the housing. Place the new thermostat in the manifold, then the new gasket in the proper position and finally the housing back on the manifold. Carefully tighten the bolts back in place (there is actually a torque spec for these two bolts) then reattach the rad hose and add new coolant to bring the fluid up to its required level.

First answer by Me42. Last edit by Me42. Contributor trust: 8 [recommend contributor]. Question popularity: 5 [recommend question]