How do I change the thermostat on a 1998 Toyota Tacoma?

Answer 1

You didn't specify the engine size, but all Toyota engines have the thermostat located under the upper radiator hose water inlet connection. The first step is to drain the cooling system into a suitable container. The water inlet connection is usually retained by studs with nuts. Remove the nuts, then carefully work loose the water inlet after removing the upper rad hose. Make certain to remove the gasket (usually an O-ring seal which should be replaced) with the water inlet. To install: Clean all mating parts well. The water inlet is light alloy and easily damaged. At assembly, you want the nuts to tighten down evenly to avoid distorting and cracking the water inlet. Apply a small amount of lubricant on the threads of the studs. When installing the new thermostat, always use a new seal. Be sure that the thermostat is positioned with the spring down or into the engine. Some thermostats use a jiggle valve (looks like a small rivet in the edge of the thermostat) that must be at the top or 12 o'clock position. Lubricate the new replacement O-ring seal with anti-freeze and install the water inlet. Install the nuts finger-tight making sure the water inlet is properly seated. Tighten the nuts to 10 to 14 ft. lbs. (13 to 19 Nm). Do NOT over-tighten, or the water inlet may crack. Install the hoses and wire connectors removed for access. Make certain the coolant hoses are not kinked or twisted after installation. . Fill the cooling system with coolant, start the engine and check for leaks