Hyundai Coupes/Sedans 1994-1998 Repair Guide

Engine Coolant



Hyundai recommends the use of a good quality ethylene glycol based or other aluminum compatible antifreeze. It is best to add a 50/50 mix of antifreeze and water to avoid diluting the coolant in the system.


See Figures 1, 2 and 3

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Fig. Fig. 1: NEVER remove the radiator cap when the engine is HOT

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Fig. Fig. 2: The reserve tank fills with coolant when the engine is hot and returns it to the engine as it cools

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Fig. Fig. 3: Add antifreeze and water to the reserve tank to keep the system full. Do not exceed the FULL mark

Any time you have the hood open, glance at the coolant reserve tank to make sure it is properly filled. Top off the cooling system using the recovery tank and its LOW and FULL markings as a guideline. If you top off the system, make a note to check it again soon.

Never overfill the reserve tank.

A coolant level that consistently drops is usually a sign of a small, hard to detect leak, although in the worst case it could be a sign of an internal engine leak (blown head gasket/cracked block- ... check the engine oil for coolant contamination). In most cases, you will be able to trace the leak to a loose fitting or damaged hose.

Evaporating ethylene glycol antifreeze will leave small, white (salt-like) deposits, which can be helpful in tracing a leak.


See Figures 4 and 5

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Fig. Fig. 4: The petcock is located at the bottom corner of the radiator

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Fig. Fig. 5: Fill the radiator to the filler neck seat with a 50/50 mixture of antifreeze and water

When draining coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze, and are 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.

Ensure that the engine is completely cool prior to starting this service.

  1. Remove the radiator and reserve tank caps.
  3. Place a drain pan of sufficient capacity under the radiator and open the petcock (drain).

The petcock is plastic and easily binds. Before opening the radiator petcock, spray it with some penetrating lubricant.

  1. When the system is completely drained, close the petcock and fill the system with a radiator cleaning fluid (clean water may also be used, but is not as efficient).
  3. Idle the engine until the upper radiator hose gets hot.
  5. Allow the engine to cool and drain the system again.
  7. Repeat this process until the drained water is clear and free of scale.
  9. Flush the reserve tank with water and leave empty.
  11. Determine the capacity of the coolant system, then properly refill the cooling system with a 50/50 mixture of fresh coolant and water, as follows:
    1. Fill the radiator with coolant until it reaches the radiator filler neck seat.
    3. Start the engine and allow it to idle until the thermostat opens (the upper radiator hose will become hot).
    5. Turn the engine OFF and refill the radiator until the coolant level is at the filler neck seat.
    7. Fill the engine coolant overflow tank with coolant to the FULL mark, then install the radiator cap.

  13. If available, install a pressure tester and check for leaks. If a pressure tester is not available, run the engine until normal operating temperature is reached (allowing the system to naturally pressurize), then check for leaks.
  15. Check the level of protection with an antifreeze/coolant hydrometer.