How to Flush the Radiator on a 1993 Nissan Quest

The 1993 Nissan Quest is equipped with an internal cooling system like most vehicles. The internal cooling system circulates coolant throughout the engine and passes it through the radiator. The radiator is made up of cooling coils that pass fluid back and forth in front of a cooling fan so that the coolant maintains the proper temperature to prevent the engine from overheating. The engine coolant becomes contaminated over a predictable amount of time and will need to be flushed out of the cooling system.

Tools Used: Tools, Engine coolant, Large drain pan

Flush the Radiator

Wait for the engine to cool down completely. Locate the radiator cap and turn it counterclockwise by hand to open. The radiator cap is located on the top right side of the radiator. The cap is a pressure type cap that will need to be pushed down by hand and then turned, as indicated, to loosen and remove.

Locate the drain valve under the radiator. The drain valve is located on the bottom right side of the radiator. The valve is a petcock type valve that can be opened and closed by hand. Place a large drain pan under the radiator drain valve. Open the drain valve by turning the valve counterclockwise by hand.

Allow all the coolant to drain into the drain pan until there is just a slow drip. Move the drain pan from under the radiator and use a garden hose to pass water through the top of the radiator where you removed the cap then through the radiator and out of the drain valve until the water comes out clear.

Close the drain valve by it turning clockwise by hand until tight. Fill the radiator up to the neck at the top of the radiator. Replace the radiator by pushing it down and turning it clockwise until it seats.

Locate the plastic overflow container. The container is located on the left side of the engine up against the firewall. Fill the overflow tank with new coolant until it reaches the full cold level marked on the side of the container. Start the vehicle and allow it to come up to operating temperature. Turn the heater to maximum heat so that the heater core can fill with coolant.

Monitor the coolant level in the overflow tank. Two things should happen. Air bubbles will come up through the overflow tank, and the level will drop as the air pockets are filled with fluid and the heater core fills up. Add coolant, once the coolant level stops dropping, until it reaches the full hot level marked on the side of the container.

Tips & Warnings

Make sure to flush until all the sediment at the bottom of the radiator comes out. Verify that the heater is turned to the max setting so that the heater core will fill with coolant. If you don’t open the heater core, the coolant level will not read correctly. Do not attempt this procedure until the engine is completely cooled down. Severe burns will result otherwise. Don’t forget to close the drain valve before adding coolant. This is an easy step to miss that will cause you to lose your new coolant.


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