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Home >> Cadillac >> 2010 >> STS 3.6 V, AWD >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Cooling System >> Diagnostic Information and Procedures >> Loss of Coolant (LH2, LLT)

Loss of Coolant (LH2, LLT)

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  Refer to Symptoms - Engine Cooling 
2 Repair any present DTCs. Refer to Diagnostic Starting Point - Vehicle .
Is the action complete?		 Go to Step 3  -
3 Inspect the coolant level at the surge tank.
Is the coolant at the proper level?		 Go to Step 5  Go to Step 4 
4 Fill the cooling system to the proper level. Refer to Cooling System Draining and Filling (Static Fill)  or Cooling System Draining and Filling (GE 47716) .
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 24 
6 Engine overheating can cause a loss of coolant.
Is the engine overheating?		 Go to Step 25  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 27  Go to Step 8 
8 Visually inspect the hoses, pipes and hose clamps at the following locations:
  • Surge tank
  • Throttle body
  • Water pump
  • Heater core
  • Radiator

Are any of the hoses, clamps or pipes leaking?		 Go to Step 20  Go to Step 9 
9 Visually inspect the following components:
  • Block heater
  • Coolant pressure cap
  • Core plugs
  • Cylinder head gaskets
  • Cylinder heads
  • Engine block
  • Radiator
  • Thermostat housing
  • Water pump

Are any of the listed components leaking?		 Go to Step 20  Go to Step 10 
10
  1. Pressure test the cooling system. Refer to Cooling System Leak Testing (Powertrain) .
  2. With the cooling system pressurized, visually inspect the components listed in steps 8 and 9.
Are any leaks present?		 Go to Step 20  Go to Step 11 
11 Pressure test the coolant pressure cap. Refer to Pressure Cap Testing (Powertrain) .
Does the coolant pressure cap hold pressure?		 Go to Step 12  Go to Step 21 
12
  1. Apply the parking brake.
  2. Ensure the vehicle is in PARK.
  3. Start and idle the engine until it reaches normal operating temperature.
  4. Inspect for heavy white smoke coming out of the exhaust pipe.
Is a heavy white smoke present from the exhaust pipe?		 Go to Step 13  Go to Step 14 
13
  • 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 26  Go to Step 14 
14
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 28  Go to Step 15 
15 Inspect for the following conditions:
  • A coolant smell inside of the vehicle.
  • Coolant in the HVAC module drain tube.
  • Coolant on the vehicle floor covering near the HVAC 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 GM P/N 89022219 (Canadian P/N 89022220) to the cooling system for each 15 liters (4 gallons) of coolant. Refer to 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 20  Go to Step 17 
17 Use J 42220  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 22  Go to Step 18 
18 Inspect the engine oil for a gray/white milky substance.
Is there a milky substance in the engine oil ?		 Go to Step 26  Go to Step 19 
19 Inspect the transmission oil fluid for a gray/white milky substance.
Does the transmission fluid contain a gray/white milky substance?		 Go to Step 23  Go to Step 29 
20 Repair or replace the leaking component. Refer to the appropriate repair.
Is the repair complete?		 Go to Step 29  -
21 Replace the coolant pressure cap.
Is the repair complete?		 Go to Step 29  -
22 Replace the heater core. Refer to Heater Core Replacement .
Is the repair complete?		 Go to Step 29  -
23
  1. Replace the radiator. Refer to Radiator Replacement (LH2 Heavy Duty Cooling)  or Radiator Replacement (LLT)  or Radiator Replacement (LH2 without V03) .
  2. Service the transmission. Refer to Engine Coolant/Water in Transmission .
Is the repair complete?		 Go to Step 29  -
24 Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate .
Is the repair complete?		 Go to Step 29  -
25 Repair the engine overheating condition. Refer to Engine Overheating .
Is the repair complete?		 Go to Step 29  -
26 Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber or Coolant in Engine Oil .
Is the repair complete?		 Go to Step 29  -
27 Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed .
Is the repair complete?		 Go to Step 29  -
28 Repair the combustion pressure in the cooling system problem. Refer to Cylinder Leakage Test .
Is the repair complete?		 Go to Step 29  -
29 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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