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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Heating And Cooling System >> Diagnostic Information and Procedures >> Loss of Coolant (LSY)

Loss of Coolant (LSY)

Special Tools 

GE-42220  Universal 12V Leak Detection Lamp

Equivalent regional tools: Special Tools 

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 LSY) , or Cooling System Draining and Filling (GE 47716 LSY) 
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 26 
6 Engine overheating can cause a loss of coolant.
Is the engine overheating?		 Go to Step 27  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 29  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 28  Go to Step 10 
10
WARNING:

Refer to Moving Parts and Hot Surfaces Warning

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

Are any of the coolant hoses, clamps or pipes leaking?		 Go to Step 21  Go to Step 12 
12 Visually inspect the following components:
  • Automatic Transmission Fluid Cooling Exchanger Assembly (at transmission), if equipped
  • Core Plugs
  • Cylinder Head Gaskets
  • Electric Water Pump
  • Engine Block
  • Engine Coolant Flow Control Valve/Block Control Valve Assembly, if equipped
  • Engine Oil Cooler Assembly
  • Integrated Manifold Assembly, if equipped
  • Radiator
  • Radiator Surge Tank Cap
  • Turbocharger Cooler, if equipped

Are any of the listed components leaking?		 Go to Step 21  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 21  Go to Step 14 
14 Pressure test the radiator surge tank cap. Radiator Surge Tank Cap Testing 
Does the coolant radiator surge tank 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 heater and air conditioning evaporator and blower module removal drain tube
  • Coolant on the vehicle floor covering near the heater and air conditioning evaporator and blower module

Is coolant present?		 Go to Step 23  Go to Step 16 
16
  1. Add 30 ml (1 oz) of coolant system tracer 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 21  Go to Step 17 
17 Use GE-42220  Universal 12V Leak Detection Lamp to inspect for the following conditions:
  • Coolant system tracer dye in the heater and air conditioning evaporator and blower module drain tube
  • Coolant system tracer dye on the vehicle floor covering near the heater and air conditioning evaporator and blower module

Is coolant dye present?		 Go to Step 23  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 28  Go to Step 20 
20 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 24  Go to Step 30 
21 Repair or replace the leaking component.
Is the repair complete?		 Go to Step 30  -
22 Replace the radiator surge tank cap.
Is the repair complete?		 Go to Step 30  -
23 Replace the heater core. Heater Core Replacement
Is the repair complete?		 Go to Step 30  -
24
  1. Pressure test the cooling system. Cooling System Leak Testing 
  2. Inspect the transmission oil cooler for coolant.
Is coolant present?		 Go to Step 25  Go to Step 30 
25
  1. Replace the automatic transmission fluid cooling exchanger. Automatic Transmission Fluid Cooling Exchanger Replacement (LSY)
  2. Service the automatic transmission. Engine Coolant/Water in Transmission
Is the repair complete?		 Go to Step 30  -
26 Repair the engine no crank condition. Engine Will Not Crank - Crankshaft Will Not Rotate
Is the repair complete?		 Go to Step 30  -
27 Repair the engine overheating condition. Engine Overheating 
Is the repair complete?		 Go to Step 30  -
28 Repair the engine internal coolant leak.
Is the repair complete?		 Go to Step 30  -
29 Repair the engine knock. Lower Engine Noise, Regardless of Engine Speed
Is the repair complete?		 Go to Step 30  -
30 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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