GM Century/Lumina/Grand Prix/Intrigue 1997-2000

Cooling System

Print

The engine is kept cool by coolant circulating through the engine to a radiator where the heat to transferred to the air. The coolant is circulated by a pump driven by the engine accessory drive belt. The complete cooling system consists of a radiator, recovery system, cooling fans (electric on these vehicles) thermostat, pump and the serpentine drive belt.

FLUID RECOMMENDATIONS



All of the vehicles covered by this guide were originally filled at the factory with GM Goodwrench DEX-COOL®. DEX-COOL® is an ethylene-glycol coolant that was developed to last for 150,000 miles (240,000 km), or 5 years, whichever occurs first. It is recommended that only DEX-COOL® be used when coolant is added or changed. It's a good idea to purchase a gallon container or two of DEX-COOL® from an authorized GM dealer so the correct antifreeze is always available. A 50/50 mixture of this ethylene-glycol coolant and water should be used, providing freezing protection down to -34°F (1°C), boiling protection to 265°F (265°C), and rust and corrosion protection for the system. A solution stronger than 70% antifreeze is not recommended and pure antifreeze will freeze at only -8°F (-22°C).



Click image to see an enlarged view

Fig. Late-model GM products use a special long-life coolant called DEX-COOL® that can NOT be mixed with other types of coolant

LEVEL CHECK



A pressure vent radiator cap is used on all models to allow a buildup of 15 psi in the cooling system. This pressure raises the boiling point of coolant to approximately 262°F. at sea level. DO NOT remove the radiator cap to check the engine coolant level.



Click image to see an enlarged view

Fig. The coolant reservoir is normally located on the fenderwall



Click image to see an enlarged view

Fig. Coolant level should be between the FULL HOT (A) and ADD (B) marks, depending on the coolant temperature



Click image to see an enlarged view

Fig. Periodically remove all debris from the radiator and air condition condenser fins

Always check the coolant level by looking through the "see through" area of the coolant recovery reservoir. Coolant should be added ONLY to the reservoir, after the system cools. Because a radiator cap, loosened when the engine is hot, will cause a loss of pressure and immediate coolant boiling, possibly with explosive force, most car makers, including GM, have designed the radiator cap in such a way that it is not easy to get a grip, to discourage inadvertent removal. Embossed on the cap is a caution against its being opened and arrows indicating the proper closed position. During routine maintenance, ALWAYS check the coolant level (and add, if required) at the coolant recovery reservoir. Refilling coolant at the radiator should only be required if the radiator and/or the cooling system has been drained.

DRAIN & REFILL



  1. With the engine cool, remove the radiator cap by slowly rotating the cap counter-clockwise to the detent (a stop that will prevent further turning). Do not press down while rotating the pressure cap. Wait until any residual pressure (indicated by a hissing sound) is relieved. After all hissing stops, continue to rotate counter-clockwise until the cap is removed.
  2.  



Click image to see an enlarged view

Fig. The radiator caps used on these vehicle have no handles to discourage removing the cap when the engine hot.



Click image to see an enlarged view

Fig. Location of the drain valve (1) and drain hole (2)



Click image to see an enlarged view

Fig. When draining the cooling system, placing a piece of tubing over the drain valve may help control spills



Click image to see an enlarged view

Fig. Fill the radiator to the bottom of the filler neck with a 50/50 mix of DEX-COOL® and clean water



Click image to see an enlarged view

Fig. Be sure to refill the coolant recovery reservoir with a 50/50 mix of DEX-COOL® and clean water



Click image to see an enlarged view

Fig. Another coolant recovery reservoir showing the upper and lower limit marks. This tank is stained because of coolant contamination due to a gasket failure


NOTE
Dispose of used coolant in a proper fashion, such as recovering the coolant and storing the used coolant in a container for recycling. NEVER POUR USED COOLANT DOWN A DRAIN. Ethylene glycol is a very toxic chemical. Disposing of it into the sewer system or ground water is illegal and ecologically unsound. Keep children and pets away from open containers of coolant.

  1. Place a drain pan under the vehicle to collect all of the drained coolant.
  2.  
  3. Open the radiator drain valve located at the bottom of the radiator tank. For procedures requiring the cooling system to be partially drained, opening the radiator drain valve should provide sufficient draining and no further action should be necessary.
  4.  
  5. Locate and open the air bleed vent(s). They are generally located on the thermostat housing. The air bleed vent should be opened two to three turns.
  6.  
  7. Allow the coolant to completely drain from the radiator.
  8.  
  9. Close the radiator drain valve.
  10.  
  11. Slowly fill the cooling system through the radiator neck using the following procedure:
    1. If the coolant system has been flushed (block drains opened), first add 100% DEX-COOL®. For the 3.1L engine, use 5.8 quarts; for the 3.8L engines, use 5.3 quarts; for the 3.4L engine, use 6.1 quarts.
    2.  
    3. Then slowly add clean water to the system until the level of the coolant mixture has reached the base of the radiator neck.
    4.  
    5. Wait for two minutes and recheck the level of the coolant mixture, and add clean water if necessary to restore the coolant mixture level to the base of the radiator neck.
    6.  

  12.  
  13. If the cooling system is being refilled ONLY (no flush), simply use a 50/50 mix of coolant and water to refill.
  14.  
  15. Install the radiator cap making certain that the arrows line up with the overflow tube.
  16.  



Click image to see an enlarged view

Fig. The screwdriver is shown on the coolant bleed valve. It is made of brass and easily damaged so do not overtighten-3.1L engine shown

  1. Close the air bleed valve(s). DO NOT OVERTIGHTEN. The bleed valve is made of brass and easily damaged.
  2.  
  3. Fill the coolant reservoir as required to bring the 50/50 mix to the COLD level mark on the reservoir.
  4.  
  5. Start the engine and check for leaks.
  6.  


CAUTION
When checking for leaks with the system at normal operating temperature, BE EXTREMELY CAREFUL not to touch any moving or hot engine parts. Once operating temperature has been reached, shut the engine OFF , and check for leaks around the hose fittings and connections that were removed earlier.


NOTE
The low coolant indicator lamp may come on after this procedure. After operating the vehicle so that the engine heats up and cools down three times, if the low coolant indicator lamp does NOT go out, or fails to come on at ignition check, and the coolant is at the proper level, further diagnosis may be required. If at any time the "TEMP" warning indicator comes on, immediate action is required.

FLUSH AND CLEANING



  1. Refer to the drain and fill procedure in this section, then drain the cooling system.
  2.  
  3. Close the drain valve.
  4.  


NOTE
Your GM W-Body vehicle uses an aluminum radiator with plastic tanks, and the coolant comes into contact with numerous aluminum parts in the cooling system. Many coolant system flushing chemicals are extremely caustic and will attack aluminum parts. Make absolutely sure any chemical flushing solution is compatible with and safe to use with aluminum cooling system components. Follow the directions on the container.

  1. If using a flushing solution, remove the thermostat. Reinstall the thermostat housing.
  2.  
  3. Add sufficient water to fill the system.
  4.  
  5. Start the engine and run for a few minutes. Shut the engine OFF . Drain the cooling system.
  6.  
  7. With the engine OFF , and if using a flushing solution, disconnect the heater hose to the heater core, usually at the firewall. Connect a water hose to end of the heater hose and run water into the system until it begins to flow out of the top of the radiator.
  8.  
  9. Allow the water to flow out of the radiator until it is clear.
  10.  
  11. Reconnect the heater hose.
  12.  
  13. Drain the cooling system again.
  14.  
  15. Reinstall the thermostat.
  16.  
  17. Empty the coolant reservoir or surge tank and flush it.
  18.  
  19. Fill the cooling system using the correct ratio of antifreeze and water, to the bottom of the radiator filler neck. Fill the reservoir or surge tank to the FULL mark.
  20.  
  21. Install the radiator cap, making sure the arrows align with the overflow tube.
  22.  

 
label.common.footer.alt.autozoneLogo