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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 2 (Engine Heating And Cooling System) >> Diagnostic Information and Procedures >> Loss of Coolant

Loss of Coolant

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.
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 (Static Fill LWN) , or Cooling System Draining and Filling (GE 47716 LWN) , or Cooling System Draining and Filling (Static LC8, LV1, L96) , or Cooling System Draining and Filling (GE47716 LC8, LV1, L96) 
Is the action complete?		 Go to Step 5  -
5 If the engine is suspected to have a coolant leak into the cylinder, the coolant can hydraulically lock the cylinder.
Does the engine crankshaft rotate?		 Go to Step 6  Go to Step 31 
6 Engine overheating can cause a loss of coolant.
Is the engine overheating?		 Go to Step 32  Go to Step 7 
7 Extended engine operation with a low coolant level can cause engine internal component failure.
Is the engine knocking?		 Go to Step 34  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 33  Go to Step 10 
10 With the engine idling, inspect the coolant recovery system.
Does the coolant recovery system 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:
  • Auxiliary heater
  • Coolant bypass
  • Coolant crossover
  • Coolant reservoir
  • Heater
  • Hot water shut-off valve
  • Radiator

Are any of the hoses, clamps, or pipes leaking?		 Go to Step 22  Go to Step 12 
12 Visually inspect the following components:
  • Coolant pressure cap
  • Coolant reservoir
  • Core plugs
  • Cylinder head gaskets
  • Engine block
  • Hot water shut-off valve
  • Intake manifold
  • Radiator
  • Thermostat
  • Water pump

Are any of the listed components leaking?		 Go to Step 22  Go to Step 13 
13
  1. Pressure test the cooling system. Cooling System Leak Testing (LWN) , or Cooling System Leak Testing (LC8, LV1, L96) 
  2. Visually inspect the components listed in steps 11 and 12 again.
Are any leaks present?		 Go to Step 22  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 22 
15 Inspect for the following conditions:
  • A coolant smell inside of the vehicle
  • Coolant in the HVAC module drain tube
  • Coolant on the vehicles floor covering under the HVAC module

Is coolant present?		 Go to Step 24  Go to Step 16 
16 If equipped with auxiliary heating, inspect for the following:
  • A coolant smell inside of the vehicle
  • Coolant in the auxiliary HVAC module drain tube
  • Coolant on the floor covering near the auxiliary HVAC module

Is coolant present?		 Go to Step 25  Go to Step 17 
17
  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. Approximate Fluid Capacities
  2. Start the vehicle and allow the engine to reach normal operating temperature.
  3. Shut the engine Off.
  4. Use J 42220  universal 12v leak detection lamp to visually inspect the components listed in steps 11 and 12.
Are any leaks present?		 Go to Step 22  Go to Step 18 
18 Use J 42220  universal 12v leak detection lamp to inspect for the following conditions:
  • Coolant dye in the HVAC module drain tube
  • Coolant dye on the vehicle floor covering near the HVAC module

Is coolant dye present?		 Go to Step 24  Go to Step 19 
19 Inspect the underside of the oil fill cap for a gray/white milky substance.
Is there a milky substance under the oil fill cap?		 Go to Step 20  Go to Step 21 
20 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 26  Go to Step 21 
21 Inspect the automatic transmission oil fluid level indicator, if equipped, for a gray/white milky substance.
Is there a milky substance on the automatic transmission fluid level indicator?		 Go to Step 28  Go to Step 36 
22 Repair or replace the leaking component.
Is the repair complete?		 Go to Step 36  -
23 Replace the coolant pressure cap.
Is the repair complete?		 Go to Step 36  -
24 Replace the heater core. Heater Core Replacement (C60) , or Heater Core Replacement (C42)
Is the repair complete?		 Go to Step 36  -
25 Replace the auxiliary heater core. Auxiliary Heater Core Replacement (C36 Cargo Van) , or Auxiliary Heater Core Replacement (Passenger Van C69)
Is the repair complete?		 Go to Step 36  -
26
  1. Remove the engine oil cooler lines from the radiator.
  2. Pressure test the cooling system. Cooling System Leak Testing (LWN) , or Cooling System Leak Testing (LC8, LV1, L96) 
  3. Inspect the engine oil cooler for coolant.
Is coolant present in the engine oil cooler?		 Go to Step 27  Go to Step 30 
27
  1. Replace the radiator. Radiator Replacement (LWN) , or Radiator Replacement (LV1) , or Radiator Replacement (L96, LC8) 
  2. Service the engine oil and filter.
Is the repair complete?		 Go to Step 36  -
28
  1. Remove the transmission oil cooler lines from the radiator.
  2. Pressure test the cooling system. Cooling System Leak Testing (LWN) , or Cooling System Leak Testing (LC8, LV1, L96) 
  3. Inspect the transmission oil cooler for coolant.
Is coolant present in the transmission oil cooler?		 Go to Step 29  Go to Step 30 
29
  1. Replace the radiator. Radiator Replacement (LWN) , or Radiator Replacement (LV1) , or Radiator Replacement (L96, LC8) 
  2. Service the automatic transmission. Engine Coolant/Water in Transmission , for the 6L90 transmission or Engine Coolant/Water in Transmission for the 8L90.
Is the repair complete?		 Go to Step 36  -
30 Install the cooler lines to the radiator.
Is the action complete?		 Go to Step 36  -
31 Repair the engine no crank condition.
Is the repair complete?		 Go to Step 36  -
32 Repair the engine overheating condition. Engine Overheating 
Is the repair complete?		 Go to Step 36  -
33 Repair the engine internal coolant leak.
Is the repair complete?		 Go to Step 36  -
34 Repair the engine knock.
Is the repair complete?		 Go to Step 36  -
35 Repair the combustion pressure in the cooling system problem.
Is the repair complete?		 Go to Step 36  -
36 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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