A good drain flush and refill will restore the coolant's recommended fluid ratio and prevent corrosion build up in the coolant system. Make sure the engine is cool before draining the system. Move the temperature knob on the heater control to hot. Remove the plastic shrouds under the radiator to locate the radiator drain. You'll need a large phillips screwdriver to remove the plug. Get a large drain pan under the drain to catch the fluid. Once the fluid stops draining, move the pan under the block and remove the air bleed plug (the GA16DE engine has an air bleed plug at the end of the cylinder head below the inside distributor retaining bolt and SR20DE models have a bleeder plug on the thermostate housing). This allows the coolant to drain out of the block. While draining, check the coolant hoses like the Cooling System Check above. Use a garden hose and flush the system with water. Flush until the water coming out of the drain is clear. This should remove any loose sediments. You should also buy a chemical cleaner specially made for flushing coolant systems. Follow the directions on the cleaner you purchase to perform a good flush. Be sure to empty the coolant reservoir and clean the components of that too. Install the radiator drain plug and fill the system until the radiator is full or the coolant is commong out of the air bleed valve. Install the air bleed valve and fill the coolant reservoir. Start the engine with the radiator cap off. Wait till the thermostate opens and starts circulating the fluid throughout the engine. Keep adding fluid while it takes it. Once the thermostate closes, the fluid will stop circulating. Just wait till it opens before adding more fluid. Squeeze the upper and lower radiator hoses to purge any air bubbles. When you get to a point where you can't add any more fluid, install the radiator cap, shut the engine off and allow it to cool. As the engine cools it will suck fluid from the reservoir to fill the rest of the system. Make sure you add enough fluid to the reservoir. Once the engine is cool, remove the radiator cap and check the level. If you have too much air in the system, fluid will not be suctioned into the system. Top of the radiator and the reservoir if needed. Run the engine and fill the system until the fluid level maintains the full positions on the reservoir.
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