CTS 2003-2005

Hoses

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CAUTION
These vehicles are equipped with electric underhood cooling fans. An electric fan can start up even when the engine is not running and can injure you. Keep hands, clothing and tools away from any underhood electric fan.

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



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



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



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



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



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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.
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  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.
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  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.
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  7. Allow the coolant to completely drain from the radiator.
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  9. Close the radiator drain valve.
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  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.
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    3. Then slowly add clean water to the system until the level of the coolant mixture has reached the base of the radiator neck.
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    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.
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  13. If the cooling system is being refilled ONLY (no flush), simply use a 50/50 mix of coolant and water to refill.
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  15. Install the radiator cap making certain that the arrows line up with the overflow tube.
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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.
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  3. Fill the coolant reservoir as required to bring the 50/50 mix to the COLD level mark on the reservoir.
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  5. Start the engine and check for leaks.
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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.

  1. Refer to the drain and fill procedure in this section, then drain the cooling system.
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  3. Close the drain valve.
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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.
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  3. Add sufficient water to fill the system.
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  5. Start the engine and run for a few minutes. Shut the engine OFF . Drain the cooling system.
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  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.
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  9. Allow the water to flow out of the radiator until it is clear.
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  11. Reconnect the heater hose.
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  13. Drain the cooling system again.
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  15. Reinstall the thermostat.
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  17. Empty the coolant reservoir or surge tank and flush it.
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  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.
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  21. Install the radiator cap, making sure the arrows align with the overflow tube.
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