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Home >> Buick >> 2008 >> Allure CXL >> Repair and Diagnosis >> Engine Mechanical >> Cooling System (Mechanical) >> Engine Cooling System >> Diagnostic Information and Procedures >> Loss of Coolant

Loss of Coolant

Step Action Yes No
DEFINITION: The cooling system is loosing 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 6  Go to Step 4 
4 Fill the cooling system to the proper level. Refer to Cooling System Draining and Filling (L26, LY7 GE 47716 Fill)  or Cooling System Draining and Filling (L26 Static Fill)  or Cooling System Draining and Filling (LY7 Static Fill)  or Cooling System Draining and Filling (LS4 GE47716 Fill)  or Cooling System Draining and Filling (LS4 Static Fill) .
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 With the engine idling, inspect the coolant recovery system.
Does the coolant recovery system 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 bypass
  • Coolant reservoir
  • 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:
  • Block heater
  • Coolant pressure cap
  • Core plugs
  • Cylinder head gaskets
  • Engine block
  • Intake manifold
  • Radiator
  • Thermostat housing
  • Water pump

Are any of the listed components leaking?		 Go to Step 20  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 20  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 21 
15 Pressure test the coolant pressure cap. Refer to Pressure Cap Testing .
Does the coolant pressure cap hold pressure?		 Go to Step 30  Go to Step 21 
16 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 near the HVAC module

Is coolant present?		 Go to Step 22  Go to Step 17 
17 Inspect the underside of the engine oil fill cap for a gray/white milky substance.
Is there a milky substance on the oil fill cap?		 Go to Step 18  Go to Step 19 
18 Inspect the engine oil fluid level indicator for a gray/white milky substance.
Is there a milky substance on the engine fluid level indicator?		 Go to Step 28  Go to Step 19 
19 Inspect the automatic transmission oil fluid level indicator for a gray/white milky substance.
Is there a milky substance on the automatic transmission fluid level indicator?		 Go to Step 23  Go to Step 31 
20 Repair or replace the leaking component. Refer to the appropriate repair.
Is the repair complete?		 Go to Step 31  -
21 Replace the coolant pressure cap.
Is the repair complete?		 Go to Step 31  -
22 Replace the heater core. Refer to Heater Core Replacement .
Is the repair complete?		 Go to Step 31  -
23
  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 24  Go to Step 25 
24
  1. Replace the radiator. Refer to Radiator Replacement (L26, LY7)  or Radiator Replacement (LS4) .
  2. Service the automatic transmission. Refer to Engine Coolant/Water in Transmission .
Is the repair complete?		 Go to Step 31  -
25 Install the cooler lines to the radiator.
Is the repair complete?		 Go to Step 31  -
26 Repair the engine no crank condition. Refer to the appropriate procedure:
Is the repair complete?		 Go to Step 31  -
27 Repair the engine overheating condition. Refer to Engine Overheating .
Is the repair complete?		 Go to Step 31  -
28 Repair the engine internal coolant leak. Refer to the appropriate procedure:
Is the repair complete?		 Go to Step 31  -
29 Repair the engine knock. Refer to the appropriate procedure:
Is the repair complete?		 Go to Step 31  -
30 Repair the combustion pressure in the cooling system problem. Refer to the appropriate procedure:
Is the repair complete?		 Go to Step 31  -
31 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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