Toyota Tercel 1984-1994 Repair Guide

Cooling System



The correct coolant for the Tercel is any permanent, high quality ethylene glycol antifreeze mixed in a 50-50 concentration with water. This mixture gives the best combination of antifreeze and anti-boil characteristics within the engine.


See Figures 1 and 2

Always allow the car to sit and cool for an hour or so (longer is better) before removing the radiator cap. To avoid injury when working on a warm engine, cover the radiator cap with a thick cloth and turn it slowly counterclockwise until the pressure begins to escape. After the pressure has completely escaped, remove the cap. Never remove the cap until the pressure is released.

It's best to check the coolant level when the engine is COLD. The radiator coolant level should be between the LOW and the FULL lines on the expansion tank when the engine is cold. If low, check for leakage and add coolant up to the FULL line but do not overfill it.

Check the freeze protection rating of the antifreeze at least once a year or as necessary with a suitable antifreeze tester.

Click image to see an enlarged view

Fig. Fig. 1: A common expansion tank location

Click image to see an enlarged view

Fig. Fig. 2: Adding coolant to the expansion tank


See Figures 3, 4 and 5

The engine coolant should be changed every 30,000 miles (48,200 km) or 2 years, whichever comes first. Replacing the coolant is necessary to remove the scale, rust and chemical by-products which build up in the system.

  1. Draining the cooling system is always done with the motor COLD .
  3. Remove the radiator cap.
  5. Position the drain pan under the drain cock on the bottom of the radiator. Additionally, some engines have a drain cock on the side of the engine block, near the oil filter. This should be opened to aid in draining the cooling system completely. If for some reason the radiator drain cock can't be used, you can loosen and remove the lower radiator hose at its joint to the radiator.

When draining the coolant, keep in mind that cats and dogs are attracted by ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. If the lower hose is to be used as the drain, loosen the clamp on the hose and slide it back so it's out of the way. Gently break the grip of the hose on its fitting by twisting or prying with a suitable tool. Do not exert too much force or you will damage the radiator fitting. Remove the hose end from the radiator and direct the hose into the drain pan. You now have fluid running from both the hose and the radiator.
  3. When the system stops draining, close both draincocks as necessary.
  5. Using a funnel if necessary, fill the radiator with a 50-50 solution of antifreeze and water. Allow time for the fluid to run through the hoses and into the engine.
  7. Fill the radiator to just below the neck. With the radiator cap off, start the engine and let it idle; this will circulate the coolant and begin to eliminate air in the system. Top up the radiator as the level drops.
  9. When the level is reasonably stable, shut the engine OFF , then replace the radiator cap. Fill the expansion tank to a level halfway between the LOW and FULL lines, then cap the expansion tank.
  11. Drive the car for 10 or 15 minutes; the temperature gauge should be fully within the normal operating range. It is helpful to set the heater to its hottest setting while driving - this circulates the coolant throughout the entire system and helps eliminate air bubbles.
  13. After the engine has cooled (2-3 hours), check the level in the radiator and the expansion tank adding coolant as necessary.

Click image to see an enlarged view

Fig. Fig. 3: Place a container under the radiator draincock to catch the coolant

Click image to see an enlarged view

Fig. Fig. 4: Most engines have a coolant drain plug located in the engine block as well

Click image to see an enlarged view

Fig. Fig. 5: Adding coolant to the radiator


Proceed with draining the system as outlined earlier. When the system has drained, reconnect any hoses and close the radiator draincock. Move the temperature control for the heater to its hottest position; this allows the heater core to be flushed as well. Using a garden hose or bucket, fill the radiator and allow the water to run out the engine drain cock. Continue until the water runs clear. Be sure to clean the expansion tank as well.

If the system is badly contaminated with rust or scale,you can use a commercial flushing solution to clean it out. Follow the manufacturer's instructions. Some causes of rust are air in the system, failure to change the coolant regularly, use of excessively hard or soft water, and/or failure to use the correct mix of antifreeze and water.

After the system has been flushed, continue with the refill procedures outlined earlier. Check the condition of the radiator cap and its gasket, replacing the radiator cap as necessary.