Toyota Celica/Supra 1971-1985 Repair Guide

Cooling System

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FLUID LEVEL CHECK



See Figure 1



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Fig. Fig. 1: Check the coolant level in the expansion tank on models with a closed cooling system

Dealing with the cooling system can be a tricky matter unless the proper precautions are observed. It is best to check the coolant level in the radiator when the engine is cold. This is done by removing the radiator cap and seeing that the coolant is within 3 / 4 inch of the bottom of the filler neck. On later models, the cooling system has, as one of its components, an expansion tank. If coolant is visible above the "Low" mark on the tank, the level is satisfactory. Always be certain that the filler caps on both the radiator and the reservoir are tightly closed.

In the event that the coolant level must be checked when the engine is warm or on an engine without an expansion tank, place a thick rag over the radiator cap and slowly turn the cap counterclockwise until it reaches the first detent. Allow all the hot steam to escape. This will allow the pressure in the system to drop gradually, preventing an explosion of hot coolant. When the hissing noise stops, remove the cap the rest of the way.

If the coolant level is low, add equal amounts of ethylene glycol based (or other suitable) antifreeze and clean water. On models without an expansion tank, add coolant through the radiator filler neck. Fill the expansion tank to the "Full" level on cars with that system.


WARNING
Never add cold coolant to a hot engine unless the engine is running, to avoid cracking the engine block.

INSPECTION



See Figures 2, 3, 4 and 5



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Fig. Fig. 2: Be sure the rubber gasket on the radiator cap has a tight seal



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Fig. Fig. 3: Cooling systems should be pressure tested for leaks periodically



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Fig. Fig. 4: Periodically remove all debris from the radiator fins



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Fig. Fig. 5: The freezing protection level can be checked with an antifreeze tester

The radiator hoses and clamps and the radiator cap should be checked at the same time as the coolant level. Hoses which are brittle, cracked, or swollen should be replaced. Clamps should be checked for tightness (screwdriver tight only! Do not allow the clamp to cut into the hose or crush the fitting). The radiator cap gasket should be checked for any obvious tears, cracks or swelling, or any signs of incorrect seating in the radiator neck. If a leak is suspected, pressure test the cooling system, following the tester's instructions.

Also make sure that the radiator fins are free of leaves and other debris. Such obstructions can impede air flow, resulting in a hotter running engine.

It's a good idea to check the coolant every time that you stop for fuel. If the engine is hot, let it cool for a few minutes before checking the level.

Check the freezing protection rating at least once a year, preferably just before the winter sets in. This can be done with an antifreeze tester (most service stations will have one on hand and will probably check it for you, if not, they are available at auto parts stores. The tester, shaped like a kitchen baster, has a float or balls inside which (when floating) indicate the strength of the coolant and the protection it will give. Be sure to draw only enough coolant into the tester to lift the float or balls; don't let it fill up all at once, or you will not have an accurate reading.

DRAIN, FLUSH AND REFILL SYSTEM



See Figures 6 through 16

The cooling system should be drained, thoroughly flushed and refilled at least every 25,000-30,000 miles (40,225-48,270 km). This should be done with the engine cold.

  1. Remove the radiator cap and the expansion tank cap (if so equipped).
  2.  

It may be necessary to remove the lower engine shield prior to loosening the drain plug.

  1. Remove the two coolant drain plugs and drain the coolant. The drain plugs on all four-cylinder engines are located on the bottom of the radiator and on the left side of the engine block. On the six-cylinder engines, the plugs are on the bottom of the radiator and on the right side of the engine block (under the manifold).
  2.  
  3. Flush the cooling system (this should be done once in the spring and again in the fall) with a quality radiator flush. Follow instructions on the can. The drained coolant can be reused if it is still a strong mixture and is clean.
  4.  
  5. Replace the plugs and add a 50/50 mixture of ethylene glycol or other suitable antifreeze and water. See the Capacities chart for the correct amount of coolant.
  6.  
  7. Run the engine for a few minutes and check the coolant level; if necessary, top it off.
  8.  



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Fig. Fig. 6: Cutaway view of a typical cooling system flow



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Fig. Fig. 7: Drain plug locations for the four-cylinder engines



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Fig. Fig. 8: Drain plug locations for the 4M-E and 5M-E engines



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Fig. Fig. 9: Drain plug locations for the 5MG-E engine



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Fig. Fig. 10: If necessary, loosen the retaining bolts ...



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Fig. Fig. 11: ... and remove the lower engine shield



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Fig. Fig. 12: Position a drain pan, then loosen the drain plug and stand back



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Fig. Fig. 13: Make sure you drain all of the fluid



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Fig. Fig. 14: Refill the radiator with the engine running ...



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Fig. Fig. 15: ... then, once completely full, install the cap



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Fig. Fig. 16: Check the fluid level in the reservoir, and top off if necessary

 
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