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Home >> Cadillac >> 2017 >> XTS Base >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Cooling System >> Diagnostic Information and Procedures >> Loss of Coolant (LFX)

Loss of Coolant (LFX)

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. Refer to 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. Refer to Cooling System Draining and Filling (Static Fill) 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 28 
6 Engine overheating can cause a loss of coolant.
Is the engine overheating?		 Go to Step 29  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 31  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 30  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 15  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 22  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

Are any of the listed components leaking?		 Go to Step 22  Go to Step 13 
13
  1. Pressure test the cooling system. Refer to 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 22  Go to Step 14 
14 Pressure test the coolant pressure cap. Refer to Pressure Cap Testing .
Does the coolant pressure cap hold pressure?		 Go to Step 16  Go to Step 23 
15 Pressure test the coolant pressure cap. Refer to Pressure Cap Testing .
Does the coolant pressure cap hold pressure?		 Go to Step 32  Go to Step 23 
16 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 24  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. Refer to Adhesives, Fluids, Lubricants, and Sealers , and 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 engine oil fill cap for a gray/white milky substance.
Is there a milky substance on 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 30  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 25  Go to Step 33 
22 Repair or replace the leaking component. Refer to the appropriate repair.
Is the repair complete?		 Go to Step 33  -
23 Replace the coolant pressure cap.
Is the repair complete?		 Go to Step 33  -
24 Replace the heater core. Refer to Heater Core Replacement .
Is the repair complete?		 Go to Step 33  -
25
  1. Remove the transmission oil cooler lines from the radiator.
  2. Pressure test the cooling system. Refer to Cooling System Leak Testing .
  3. Inspect the transmission oil cooler for coolant.
Is coolant present?		 Go to Step 26  Go to Step 27 
26
  1. Replace the radiator. Refer to Radiator Replacement (LFX) .
  2. Service the automatic transmission. Refer to Engine Coolant/Water in Transmission
Is the repair complete?		 Go to Step 33  -
27 Install the cooler lines to the radiator.
Is the action complete?		 Go to Step 33  -
28 Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate
Is the repair complete?		 Go to Step 33  -
29 Repair the engine overheating condition. Refer to Engine Overheating .
Is the repair complete?		 Go to Step 33  -
30 Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber , or Coolant in Engine Oil
Is the repair complete?		 Go to Step 33  -
31 Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed
Is the repair complete?		 Go to Step 33  -
32 Repair the combustion pressure in the cooling system problem. Refer to Coolant in Combustion Chamber
Is the repair complete?		 Go to Step 33  -
33 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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