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Home >> GMC >> 2021 >> Terrain SLE, 4WD >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Heating And Cooling System >> Diagnostic Information and Procedures >> Loss of Coolant

Loss of Coolant

Step Action Yes No
DEFINITION: The cooling system is losing coolant either internally or externally.
1 Were you sent here from Symptoms or another diagnostic table? Go to Step 2  Go to Symptoms - Engine Cooling 
2 Repair any present DTCs. Diagnostic System Check - Vehicle
Is the action complete?		 Go to Step 3  -
3 Inspect the coolant level.
Is the coolant at the proper level?		 Go to Step 5  Go to Step 4 
4 Fill the cooling system to the proper level.
Cooling System Draining and Filling (GE 47716) , or
Cooling System Draining and Filling (Static) .
Is the action complete?		 Go to Step 5  -
5 If the engine is suspected to have a coolant leak into a cylinder, the coolant can hydraulically lock the engine.
Does the engine crankshaft rotate?		 Go to Step 6  Go to Step 23 
6 Engine overheating can cause a loss of coolant.
Is the engine overheating?		 Go to Step 24  Go to Step 7 
7 Extended operation with a low coolant level can cause engine internal component failure.
Is the engine knocking?		 Go to Step 26  Go to Step 8 
8
  1. Idle the engine at normal operating temperature.
  2. Inspect for heavy white smoke coming out of the exhaust pipe.
Is a heavy white smoke present from the exhaust pipe?		 Go to Step 9  Go to Step 10 
9
  • Coolant in the exhaust system creates a distinctive, burning coolant odor in the exhaust.
  • Condensation in the exhaust system can cause an odorless white smoke during engine warm up.
Does the white smoke have a burning coolant type odor?		 Go to Step 25  Go to Step 10 
10
WARNING:

Refer to Moving Parts and Hot Surfaces Warning .

With the engine idling, inspect the surge tank.Does the surge tank discharge coolant while the engine is idling?		 Go to Step 14  Go to Step 11 
11 Visually inspect the hoses, pipes and hose clamps at the following locations:
  • Coolant surge tank
  • Heater core
  • Radiator

Are any of the hoses, clamps or pipes leaking?		 Go to Step 20  Go to Step 12 
12 Visually inspect the following components:
  • The coolant pressure cap
  • The core plugs
  • The cylinder head gaskets
  • The engine block
  • The intake manifold
  • The radiator
  • The thermostat housing
  • The water pump

Check for leaks at the following location of the listed components.
  • Sealing surfaces
  • Fittings or Joints
  • Cracked or damaged components
  • Weep hole

Can you identify exact location of the leak?		 Go to Step 20  Go to Step 13 
13
  1. Pressure test the cooling system. Cooling System Leak Testing 
  2. With the cooling system pressurized, visually inspect the components listed in steps 11 and 12.
Are any leaks present?		 Go to Step 20  Go to Step 14 
14 Pressure test the coolant pressure cap. Pressure Cap Testing 
Does the coolant pressure cap hold pressure?		 Go to Step 15  Go to Step 21 
15 Inspect for the following conditions:
  • A coolant smell inside of the vehicle
  • Coolant in the air conditioning evaporator and blower module drain hose
  • Coolant on the vehicle floor covering near the heater and air conditioning evaporator and blower module

Is coolant present?		 Go to Step 22  Go to Step 16 
16
  1. Add 30 ml (1 oz.) of Extended Life Coolant Leak Detection Dye to the cooling system for each 15 liters (4 gallons) of coolant.
  2. Start the vehicle and allow the engine to reach normal operating temperature.
  3. Shut the engine off.
  4. Use GE-42220  Universal 12V Leak Detection Lamp to visually inspect the components listed in steps 11 and 12.
Are any leaks present?		 Go to Step 20  Go to Step 17 
17 Use GE-42220  Universal 12V Leak Detection Lamp to inspect for the following conditions:
  • Coolant dye in the air conditioning evaporator and blower module drain hose
  • Coolant dye on the vehicle floor covering near the heater and air conditioning evaporator and blower module

Is coolant dye present?		 Go to Step 22  Go to Step 18 
18 Inspect the underside of the engine oil fill cap for a gray/white milky substance.
Is there a milky substance on under the oil fill cap?		 Go to Step 19  Go to Step 20 
19 Inspect the engine oil fluid level indicator for a gray/white milky substance.
Is there a milky substance on the engine oil fluid level indicator?		 Go to Step 25  System OK
20 Repair or replace the leaking component. Do not replace complete component/assembly if true source of leak is a serviceable component (e.g. gasket, seal, fitting, etc.). Refer to the appropriate repair.
Is the repair complete?		 Go to Step 27  -
21 Replace the coolant pressure cap.
Is the repair complete?		 Go to Step 27  -
22 Replace the heater core. Heater Core Replacement
Is the repair complete?		 Go to Step 27  -
23 Repair the engine no crank condition.
Is the repair complete?		 Go to Step 27  -
24 Repair the engine overheating condition. Engine Overheating 
Is the repair complete?		 Go to Step 27  -
25 Repair the engine internal coolant leak.
Is the repair complete?		 Go to Step 27  -
26 Repair the engine knock.
Is the repair complete?		 Go to Step 27  -
27 Operate the system in order to verify the repair.
Did you find and correct the condition?		 System OK Go to Step 2 
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