GM Cutlass RWD 1970-1987 Repair Guide

Cooling System

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FLUID RECOMMENDATIONS



Check the coolant level in the radiator at every oil change. If the coolant level is low, refill the radiator with 50/50 solution of antifreeze (ethylene glycol) and water. Every year or 30,000 miles (48,000 km) drain, flush and refill the cooling system.

LEVEL CHECK



See Figures 1 and 2


CAUTION
Never remove the radiator cap until the engine has had ample time to cool to below operating temperature. Turn the radiator cap slowly to the first stop, and allow all the pressure to vent (indicted when the hissing noise stops). When the pressure has been released, press down and remove the cap the rest of the way.

Once a month, the engine coolant level should be checked.

On vehicles with a recovery tank, this is quickly accomplished by observing the level of coolant in the recovery tank, which is the translucent tank mounted to the right or left of the radiator, and connected to the radiator filler neck by a length of hose. As long as coolant is visible in the tank between the Full Cold and Full Hot marks the coolant level is OK.

On vehicles not equipped with a recovery tank, remove the radiator cap and observe the fluid level in the radiator.

If coolant is needed, a 50/50 mix of ethylene glycol base antifreeze and clear water should always be used for additions, both winter and summer. This is imperative on cars with air conditioning; without the antifreeze, the heater core could freeze when the air conditioning is used. Add coolant to the recovery tank through the capped opening or directly into the radiator; make additions only when the engine is cool.


CAUTION
Never remove the radiator cap until the engine has had ample time to cool to below operating temperature. Turn the radiator cap slowly to the first stop, and allow all the pressure to vent (indicted when the hissing noise stops). When the pressure has been released, press down and remove the cap the rest of the way.



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Fig. Fig. 1: Fill the radiator with a 50/50 mix of coolant and water



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Fig. Fig. 2: Remove the radiator cap

DRAINING, FLUSHING AND REFILLING



The cooling system should be drained, flushed and refilled every two years or 30,000 miles (48,000 km), according to the manufacturer's recommendations. However, many mechanics prefer to change the coolant every year; it protects against corrosion, overheating or freezing.

  1. Remove the radiator cap when the engine is cool.
  2.  


CAUTION
Never remove the radiator cap until the engine has had ample time to cool to below operating temperature. Turn the radiator cap slowly to the first stop, and allow all the pressure to vent (indicted when the hissing noise stops). When the pressure has been released, press down and remove the cap the rest of the way.

  1. Open the drain cock in the bottom of the radiator. Drain the radiator.
  2.  
  3. Close the drain cock and fill the system with clear water. A cooling system flushing additive can be added, if desired.
  4.  
  5. Run the engine until it is hot.
  6.  
  7. Drain the system, then flush with water until it runs clear.
  8.  
  9. Clean out the coolant recovery tank if equipped: remove the cap leaving the hoses in place. Remove the tank and drain it of any coolant. Clean it out with soap and water, empty it, and install it.
  10.  
  11. Close the drain cock and fill the radiator with a 50/50 mix of ethylene glycol base antifreeze and water to the base of the radiator filler neck. Fill the coolant recovery tank with the same mixture to the Full Hot mark. Install the recovery tank cap.
  12.  
  13. Run the engine until the upper radiator hose is hot again (radiator cap still off). With the engine idling, add the 50/50 mix of antifreeze and water to the radiator until the level reaches the bottom of the filler neck. Shut OFF the engine and install the radiator cap, aligning the arrows with the overflow tube. Turn off the heater.
  14.  

 
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