I got a 1986 toyota Pickup truck 22r 2wd .i replaced the batter,spark plugs an the wires,oil change,fan clutch,Radiator And the 3 water hose,Thermostat...so when im driving,it does not over heat not less im just sitting or letting it Idle..and when i shut off the truck and let it cool down,Maybe about a quart of water pushes out of the Overflow and when I put water back into the radiator it takes about a half a gallon of water...any ideas why this is happening?o yea,the truck was sitting for about 5 years too..

 

Headgasket.