GM: Electra/Park Avenue/Ninety-Eight 1990-1993

Cooling System

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The engine is kept cool by a liquid circulating through the engine to a radiator. In the radiator, the liquid is cooled by air passing through the radiator tubes. The coolant is circulated by a rotating water pump driven by the engine crankshaft. The complete engine cooling system consists of a radiator, recovery system, cooling fan, thermostat, water pump and serpentine belt.

FLUID RECOMMENDATION AND LEVEL CHECK



A see-through plastic reservoir called a coolant recovery bottle, is located in the front compartment near the radiator assembly. This bottle is connected to the radiator by a hose. As the car is driven, the coolant is heated and expands, the portion of the fluid displaced by this expansion flows from the radiator into the recovery bottle. When the car is stopped and the coolant cools and contracts, the displaced coolant is drawn back into the radiator by vacuum. Thus, the radiator is kept filled with coolant to the desired level at all times. The coolant level should be between the `add' and `full' marks on the recovery bottle. If coolant is needed, add it to the recovery bottle, not the radiator. The `add' and `full' marks on the recovery bottle are approximately one quart apart so that a 50/50 mixture can be added. (i.e. 50% ethylene glycol anti-freeze and 50% water, which is the ideal mixture).


CAUTION
Do not remove the radiator cap while the engine and radiator are still hot. This also includes the recovery bottle cap if coolant in the recovery bottle is boiling. Scalding fluid and steam can be blown out under pressure if any cap is taken off too soon. The engine cooling fan is electric and can come on whether or not the engine is running. The fan can start automatically in response to a heat sensor when the ignition is in the run position. Remember to keep hands, tools and clothing away from the cooling fan when working under the hood.

DRAIN AND REFILL





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Fig. Fig. 1 Coolant overflow reservoir



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Fig. Fig. 2 Radiator drain valve


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the 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.

The cooling system should be drained and refilled every 24 months or 30,000 miles. Please observe all cautions when working with antifreeze.

Use a good quality antifreeze with water pump lubricants, rust inhibitors and other corrosion inhibitors along with acid neutralizers. Use a permanent type coolant that meets manufacturer's specifications.

  1. When the engine is cool, open the engine compartment lid and turn the radiator cap slowly counterclockwise (without pushing down) until it reaches a stop.
  2.  
  3. Wait until any remaining pressure is released, then press down on the cap and continue turning it counterclockwise. Remove the cap.
  4.  
  5. Open the radiator drain valve and air bleed vent on the thermostat housing and bypass pipe.
  6.  
  7. Allow the system to drain completely, then close the radiator drain valve tightly.
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  9. Remove the coolant recovery bottle and clean with tap water. Reinstall the recovery bottle.
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  11. Using a 50/50 solution of antifreeze and water, fill the radiator through the radiator neck until the coolant reaches the neck.
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  13. Start the engine and let idle for five minutes; keep adding coolant until the coolant level is to the radiator neck.
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  15. Install the radiator cap. Add coolant to the recovery bottle after the engine has warmed up. The coolant level should be at the hot mark.
  16.  

The low coolant light may come on after this procedure. After operating the vehicle so that the engine heats up and cools down two times, if the low coolant indicator light does not go out, check and refill the recovery bottle.

CHECKING SYSTEM PROTECTION



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 (floating ball types) may be obtained from a local department store (automotive section) or an auto supply store. Follow the directions packaged with the coolant hydrometer when checking protection.

COOLING SYSTEM PRESSURE TESTING





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Fig. Fig. 3 Pressure testing the cooling system

  1. Tighten the radiator and heater hose clamps.
  2.  


CAUTION
To avoid being burned, do not remove the radiator cap while the engine is at normal operating temperature. The scalding coolant is under pressure and may be forced out of the filler neck, causing personal injury. Allow the engine to cool down and use a large shop towel to turn the cap.

  1. Remove the radiator cap.
  2.  
  3. Fill the system to the base of the filler neck with antifreeze.
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  5. Connect a cooling system pressure tester to the filler neck.
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  7. Build up pressure to no more than 20 psi (138 kPa). The system should hold the pressure for at least two minutes.
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  9. If the system will not hold the pressure, check for leaks.
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  11. Repair the leak and recheck the system.
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  13. Check the radiator cap also for its ability to hold pressure.
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FLUSHING AND CLEANING




CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the 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. Do not remove the radiator cap while the engine and radiator are still hot. This also includes the recovery bottle cap if coolant in the recovery bottle is boiling. Scalding fluid and steam can be blown out under pressure if any cap is taken off too soon. The engine cooling fan is electric and can come on whether or not the engine is running. The fan can start automatically in response to a heat sensor when the ignition is in run. Remember to keep hands, tools and clothing away from the cooling fan when working under the hood.

  1. Open the radiator and engine drain petcocks (models equipped), or disconnect the bottom radiator hose, at the radiator outlet, and drain the existing antifreeze and coolant. Set the heater temperature controls to the full hot position.
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  3. Close the drain plug or reconnect the lower hose and fill the system with water.
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  5. Add a can of quality radiator flush. Make sure the flush is safe to use in engines having aluminum components.
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  7. Idle the engine until the upper radiator hose gets hot.
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  9. Drain the system again.
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  11. Repeat this process until the drained water is clear and free of scale.
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  13. Close all drain plugs and connect all the hoses.
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  15. Clean the reservoir with water and leave empty.
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  17. Add a 50/50 mix of quality antifreeze (ethylene glycol) and water to provide the desired protection.
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