GM Lumina/Silhouette/Transport APVs 1990-1999 Repair Guide

Cooling System

Print

FLUID RECOMMENDATION



The cooling system was designed to maintain engine temperature at an efficient level during all engine operating conditions. Some GM vehicles came equipped with a new silicate free antifreeze. This is called DEX-COOL®. There will be a label under the hood, in the area of the coolant bottle advising of this. DEX-COOL® was developed to last for 150,000 miles (240,000km) or 5 years, whichever occurs first. Make sure only GM Goodwrench DEX-COOL® or equivalent is used when coolant is added or changed.

A 50 / 50 mixture of coolant will provide the following protection:



Freezing protection down to -37°C (-34°F)
 
Boiling protection up to 129°C (265°F), with an operating pressure cap
 
Help keep the proper engine operating temperature
 
Help protect against rust and corrosion
 
Allow the sensors and switches to operate as designed
 

DO not use a solution stronger than 70% antifreeze. Pure antifreeze will freeze at -22°C (-8°F).

LEVEL CHECK



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: If necessary, add coolant through the expansion tank

Check the coolant level in the recovery bottle or surge tank. The fluid level may be checked by observing the fluid level marks of the recovery tank. With the engine cold, the level should be at the FULL COLD or between the FULL HOT and ADD level. When the engine is at normal operating temperatures, the coolant level should be at the FULL HOT or HOT level. Only add coolant to bring the system to the proper level.


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

See Figures 2 and 3



Click image to see an enlarged view

Fig. Fig. 2: Periodically remove all debris from the radiator fins



Click image to see an enlarged view

Fig. Fig. 3: Cooling systems should be pressure tested for leaks periodically

DRAIN, FLUSH & REFILL



  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 drain valve at the bottom of the radiator. Open the block drain plugs to speed up the draining process, if so equipped.
  4.  
  5. Close the drain valves and add water until the system is full. Repeat the draining and filling process several times, until the liquid is nearly colorless.
  6.  
  7. After the last draining, fill the system with the proper mixture of coolant and water. Run the engine until the system is hot and add coolant, if necessary.
  8.  

See Figures 4 through 8

Click image to see an enlarged view

Fig. Fig. 4: If equipped, remove the splash shield to access the drain plug



Click image to see an enlarged view

Fig. Fig. 5: Loosen the drain plug ...



Click image to see an enlarged view

Fig. Fig. 6: ... and drain the coolant into a container



Click image to see an enlarged view

Fig. Fig. 7: Remove the cap to fill the radiator with coolant



Click image to see an enlarged view

Fig. Fig. 8: When installing the cap, make sure the arrows align with the overflow hose

 
label.common.footer.alt.autozoneLogo