How do you change the thermostat in a 2002 Acura RSX?

Answer 1

You have to replace the whole thermostat housing assembly. The thermostat housing can be found at the end of the lower radiator hose on the passenger side of the engine. It is jammed in there, but you can get to it without removing any other piece of the car. Two (left and right) of the three bolts can easily be removed by coming up from the underside of the car. The top bolt is easier to remove by coming down from the top of the engine compartment, setting/holding the ratchet, and then allowing another individual go underneath and do the ratcheting. It's best to have a helper with small hands to help the individual underneath guide the ratchet and hold the socket on to the bolts. This is done by using the small hands and coming down through the top, while the other individual comes up through the bottom. The bolts are 10mm and also, don't forget to drain the coolant first.