GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Charge Air Cooler System

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The 4.3L MFI-Turbo engine is equipped with a charge air cooler system. The system consists of a charge air cooler radiator, air cooler core, an electric circulation pump and the related hoses. The purpose of the system is to cool air from the turbocharger in order to produce a denser air/fuel charge for the combustion chambers. Coolant circulating through the system takes the heat from the cooler core to the charge radiator and recirculates to further cool incoming air.

FLUID RECOMMENDATIONS



The charge air cooler system should be kept full of clean, fresh antifreeze and distilled water of a 56/44 proportion of antifreeze to water.

DRAINING THE CHARGE AIR COOLER RADIATOR



  1. Remove the charge air cooler pressure cap.
  2.  
  3. Place a drain pan under the left side of the charge air cooler radiator.
  4.  
  5. Open the petcock located on the lower left side of the charge air cooler radiator.
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  7. Allow coolant to drain completely.
  8.  

BLEEDING THE SYSTEM



  1. Make sure the petcock on the charge air cooler radiator is open.
  2.  
  3. Using a premixed solution of antifreeze and distilled water (56/44 proportions), begin filling the radiator. When coolant begins to flow from the drain hole, close the petcock and continue adding coolant until the system is full.
  4.  
  5. Remove the charge air cooler pump relay, located near the coil assembly, then turn the ignition ON .
  6.  
  7. Position a jumper wire between terminals "A'' and "B'' of the relay in order to energize and run the charge air cooler system pump. Add coolant mixture to the system while the pump is running until the system is full.
  8.  
  9. Install the charge air cooler pressure cap and remove the jumper wire.
  10.  
  11. Turn the ignition OFF and install the air cooler pump relay.
  12.  

AIR COOLER RADIATOR PRESSURE TEST



  1. With the system cold, remove the charge air cooler cap and connect a pressure tester.
  2.  
  3. Apply normal system operating pressure of about 8-10 psi. DO NOT apply more than 13 psi (89 kpa) of pressure or the radiator may be damaged.
  4.  
  5. Watch the needle on the pressure gauge for a decrease in pressure which would indicate a possible leak. If pressure is lost, examine the radiator and other air cooling system components for evidence of escaping coolant.
  6.  
  7. Repair hoses, connections or components, as necessary.
  8.  
  9. Repeat the pressure test after repairs (if any) to verify proper system condition.
  10.  

 
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