This procedure will cover the draining of the coolant from the system, replacement of the thermostat, and the Engine Coolant Temperature Sensor (ECT). The most common problem with the thermostat is one of the metal brackets that holds the spring in place will break and leave the thermostat in a stuck open condition. With the thermostat stuck open your engine will not heat up to the correct operation temperature. The temperature gauge on the instrument cluster will not move to the 3:00 position when warm. With the engine not warming up, the ECU could be running your engine richer than need be, as when cold starting the fuel is set a little rich, but once the ECT sensor reaches a certain temperature the rich start condition is terminated. The draining of the coolant should be done every 2 years or 30K miles. If you have hose clamps and don't mind a little spillage then you could clamp off the hose going into the top of the radiator. The ECT sensor would be replace if the Check Engine Light were caused by a A-2 socket code of 123.

       To start the draining of the coolant from the vehicle, you need to get under the car and on the back of the engine is a 13mm petcock that when opened will drain the coolant out of the engine block. I attach a hose over the petcock and route it to a drain pan. Once you have the petcock opened, open the cap on the radiator over flow bottle and the flow will start, once drained, tighten the petcock and move to draining the radiator.

       On the driver side of the front plastic shield is a hole that has a black plastic petcock up in the hole. This 13mm petcock is on the bottom of the radiator and doesn't need tightening very much or you will break off the plastic screw, if you break it tightening it don't worry it won't leak but getting it open again will be a task.

       Once the coolant is drained from the system start by removing a few hoses. The overflow hose from the coolant bottle to the top of the thermostat housing is held in place on the housing with a 25mm screw clamp. The output of the Thermostat housing (the big hose) is held in place with a 7mm hose clamp. There are two 40mm torx screws that hold the thermostat housing in place and seated with the block housing. Notice in the picture a 7 inch long 40 torx bit is in position on the back 40mm torx screw. The 40mm torx bit makes getting the back screw out without destroying the torx fitting on top of the screw. Get one and use it or your problems will make you wish you did. (3/8 drive)

       Above shows the hoses off and the front torx screw out and the bit still on the back screw. Notice the corrosion on the pipe, clean it off with a wire brush or wire wheel if you have air tools. Once the screws are unscrewed you can leave them on the housing as you lift it up and wiggle it out, this might help to not drop the screw into the bowls of the engine never to be found.