How do you install a thermostat in a 1989 ford mustang gt?

Answer 1

Drain radiator, remove upper radiator hose. Loosen hose clamp at the bottom of the "L" shaped bypass hose that connects the thermostat housing to the water pump. Don't worry about the upper connection of the "L" shaped hose. Remove 2 bolts holding the thermostat housing to the intake manifold. One of the bolt is hard to get to, but it can be done. Be patient... and dont try to remove the water pump and timing chain cover. That bolt will come out. I use a 1/4 drive 1/2" socket with an extension to start the removal, then kind of weasel a 1/2" wrench in there to finish the removal. Once both bolts are out, remove the thermostat housing and thermostat. Once the housing is broken loose from the intake manifold, twist it until the "L" shaped hose comes off of the water pump. Now clean the thermostat housing. You MUST get all old gasket material off in order to make a good seal. Clean the mating surface of the intake manifold as well. Replace thermostat with 180 degree thermostat (I think that's what is supposed to come from the factory.) Only use a thermostat that has the same temperature as the factory thermostat. I normally put a little dab of gasket sealer on the edge of new thermostat to hold it in place while I reassemble the thermostat housing. Put a very light bead of orange (high heat) gasket sealer on the intake manifold and thermostat housing mating surfaces. I also put the new gasket on the thermostat housing. Put the "L" shaped hose back on the water pump... and don't forget to put the clamp on the hose BEFORE putting the hose on the water pump. Mate the housing to the intake and start the bolt with your fingers before putting any tools on them. The intake is made of aluminum and you DO NOT want to cross thread the bolts when you install them. Get them finger tight, then use a socket or a wrench to tighten. Also, do not over tighten them. Just a little tighter than snug is what you are looking for. The aluminum breaks easily and the bolts will break off as well if you tighten too much. Replace the upper radiator hose, tighten all hose clamps, refill radiator with a 50/50 mix of anti freeze and water. Once the radiator is full, start the car and leave the cap off the radiator. Once the new thermostat opens, the level of coolant in the radiator will drop and you will have to add more. Once this is topped off, put the cap back on and turn off the car. If you have any leaks, this is when you will find them. I also recommend that you get a meat thermometer and a pot of water and boil your new thermostat before installing it. Basically put your thermostat in a pot of cold water, put on stove and turn on the burner. Use the thermometer to verify the temperature of the water when the thermostat opens. It may not be dead on at 180 degrees, but as long as its close your ok. It will start to open well before 180, but should be fully open at 180. Once its open, remove it (tongs work well for this) from the boiling water and set in a dish. Observe it to make sure it closes fully. Once its cooled off, you can install it.