GM Caprice 1990-1993 Repair Guide

Cooling System

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NOTE
The 1992-93 Caprices are experiencing considerable radiator clogging problems, therefore it is highly recommended that the cooling system be flushed at least once a year.

FLUID RECOMMENDATION



When adding or changing the fluid in the system, create a 50/50 mixture of high quality ethylene glycol antifreeze and water.

LEVEL CHECK



The fluid level may be checked by observing the fluid level marks of the recovery tank. The level should be below the ADD mark when the system is cold. At normal operating temperatures, the level should be between the ADD and the FULL marks. Only add coolant to bring the level to the FULL mark.


CAUTION
Should it be necessary to remove the radiator cap, make sure that the system has had time to cool, reducing the internal pressure.

DRAINING AND REFILLING




CAUTION
Do not remove a radiator cap while the engine and radiator are still hot. Danger of burns by scalding fluid and steam under pressure may result!

  1. With a cool engine, slowly rotate the radiator cap counterclockwise to the detent without pressing down on the cap.
  2.  
  3. Wait until any remaining pressure is relieved by listening for a hissing sound.
  4.  
  5. After all the pressure is relieved, press down on the cap and continue to rotate the radiator cap counterclockwise.
  6.  
  7. With a suitable container to catch the fluid under the radiator, open the radiator draincock. If equipped, remove the engine block drain plugs to drain the coolant from the block.
  8.  
  9. Loosen or slide the recovery tank hose clamp at the radiator filler neck overflow tube and remove the hose. Holding the hose down to the drain pan, drain the recovery tank. Attach the hose to the filler neck overflow and tighten the clamp.
  10.  
  11. Close the radiator draincock and install the engine block drain plug.
  12.  
  13. With the engine idling, add coolant until the level reaches the bottom of the filler neck. Install the radiator cap, making sure that the arrows on the cap line up with the overflow tube.
  14.  


NOTE
Never add cold water to an overheated engine while the engine is not running.

  1. Add coolant to the recovery tank.
  2.  
  3. After filling the radiator and recovery tank, run the engine until it reaches normal operating temperature, to make sure that the thermostat has opened and all the air is bled from the system.
  4.  

FLUSHING AND CLEANING THE SYSTEM



See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: Drain plug for the cooling systemis located on the bottom of the radiator

The cooling system should be drained, thoroughly flushed and refilled at least every 30,000 miles or 24 months according to manufacturer recommendations, although it is recommended that the system be flushed once a year. These operations should be done with the engine cold.


CAUTION
To drain the cooling system, allow the engine to cool down BEFORE ATTEMPTING TO REMOVE THE RADIATOR CAP. Then turn the cap until it hisses. Wait until all pressure is off the cap before removing it completely. To avoid burns and scalding, always handle a warm radiator cap with a heavy rag.

  1. Remove the radiator and recovery tank caps. Run the engine until the upper radiator hose gets hot. This means that the thermostat is open and the coolant is flowing through the system.
  2.  
  3. Turn the engine OFF and place a large container under the radiator. Open the draincock at the bottom of the radiator. Remove the block drain plugs to speed up the draining process.
  4.  
  5. At the dash, set the heater TEMP control lever to the fully HOT position. Close the drain valve, install the block drain plug and add water until the system is full. Repeat the draining and filling process several times, until the liquid is nearly colorless.
  6.  
  7. Remove the recovery tank and rinse it out with clean water. Install the recovery tank.
  8.  
  9. After the last draining, fill the system with a 50/50 mixture of ethylene glycol and water. Run the engine until the system is hot and add coolant, if necessary. Replace the caps and check for any leaks.
  10.  

 
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