Toyota Pick-ups, Land Cruiser, and 4 Runner 1997-00

Cooling System



When additional coolant is required to maintain the proper level, always add a 50/50 mixture of ethylene-glycol antifreeze/coolant and water. Toyota specifies the use of ethylene-glycol antifreeze to not only provide freezing protection but to also prevent corrosion. The use of supplementary inhibitors or additives is neither required nor recommended.

Do NOT use alcohol type antifreeze or plain water alone.


All vehicles use a coolant reservoir tank (expansion tank) connected to the radiator by a small hose. Look through the plastic tank; the fluid level should be between FULL and LOW lines. Note that the FULL line is below the very top of the tank, allowing room for expansion. If the level in the tank is low, remove the cap of the tank and add coolant to the FULL line.

NEVER remove the radiator cap to check fluid level; there is a high risk of scalding from escaping hot fluid.

If the coolant level is low, add an equal amount of ethylene-glycol based antifreeze. Avoid using water that is known to have a high alkaline content or is very hard, except in emergency situations. Drain and flush the cooling system as soon as possible after using such water.

The radiator hoses and clamps and the radiator cap should be checked at the same time as the coolant level. Hoses that 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.

A 50/50 mix of coolant concentrate and water will usually provide protection to 35°F. (37°C). Freeze protection may be checked by using a cooling system hydrometer. Inexpensive hydrometers may be obtained from a local auto supply store. Follow the directions packaged with the coolant hydrometer when checking protection.

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Fig. The engine coolant reservoir can be used for checking fluid level and adding coolant. Simply remove the cap from the coolant recovery tank reservoir . . .

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Fig. . . . then, if the coolant is low, add an equal amount of ethylene-glycol based antifreeze and distilled water to the recovery system

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Fig. A coolant hydrometer will show you the boiling and freezing points of the coolant present


When draining 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 coolant into a sealable container. Coolant may be reused unless it is contaminated or several years old.

Completely draining and refilling the cooling system every two years will remove accumulated rust, scale and other deposits.

  1. Make certain the engine is COLD. Generally, this means at least three hours from last operation, longer in hot weather. Overnight cold is best.

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Fig. When the engine is cool, remove the radiator cap

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Fig. The petcock or plug can be removed by turning it clockwise

  1. Remove the radiator cap. Drain the existing antifreeze and coolant. Open the radiator and engine drain petcocks, or disconnect the bottom radiator hose at the radiator outlet. Set the heater temperature controls to the full HOT position.

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Fig. Radiator and engine coolant plugs3RZ-FE engine shown, others similar

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Fig. Radiator and engine coolant drain plugs1FZ-FE engine

Before opening the radiator petcock, spray it with some penetrating lubricant.

  1. Close the petcocks or reconnect the lower hose and fill the system with the correct mixture of antifreeze and water in the correct amount. It will take a bit of time for the level to stabilize within the radiator.
  3. Double check the petcocks for closure.
  5. Install the radiator cap.
  7. Flush the reservoir with water, empty it, then install fresh coolant mixture to the FULL line.
  9. Start the engine, allowing it to idle. As it warms up, keep a close watch on the petcocks and/or hose fittings used to drain the system. If any leakage is seen, shut the engine OFF and fix the leak.
  11. After the engine has warmed up, shut the engine OFF ). Check the level in the reservoir tank and adjust the fluid level as needed.

Fresh antifreeze has a detergent quality. Fluid in the reservoir may appear muddy or discolored due to the cleaning action of the new coolant. If the system has been neglected for a period of time, it may be necessary to re-drain the system to eliminate this sludge.


Several aftermarket radiator flushing and cleaning kits can be purchased at your local auto parts store. It is recommended that the radiator be cleaned and flushed of sludge and any rust build-up once a year. Manufacturers directions for proper use, and safety precautions, come in each kit.


Periodically clean any debris such as leaves, paper, insects, etc., from the radiator fins. Pick the large pieces off by hand. The smaller pieces can be washed away with water pressure from a hose.

Carefully straighten any bent radiator fins with a pair of needle nose pliers. Be careful, the fins are very soft. Do NOT wiggle the fins back and forth too much. Straighten them once and try NOT to move them again.