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Home >> Chevrolet >> 2006 >> Silverado 1500 HD, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1138 (Engine Cooling System) >> Diagnostic Information and Procedures >> Loss of Coolant

Loss of Coolant

WARNING: This page is about a different car, the 2008 Cadillac CTS. 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. Refer to Diagnostic System Check - 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 (GE 47716)  or Cooling System Draining and Filling (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 22 
6 Engine overheating can cause a loss of coolant.
Is the engine overheating?		 Go to Step 23  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 25  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 18  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 18  Go to Step 10 
10
  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 8 and 9.
Are any leaks present?		 Go to Step 18  Go to Step 11 
11 Pressure test the coolant pressure cap. Refer to Pressure Cap Testing .
Does the coolant pressure cap hold pressure?		 Go to Step 12  Go to Step 19 
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 24  Go to Step 14 
14 With the engine idling, inspect the surge tank.
Does the surge tank discharge coolant while the engine is idling?		 Go to Step 26  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 20  Go to Step 16 
16 Inspect the engine oil for a gray/white milky substance.
Is there a milky substance in the engine oil ?		 Go to Step 24  Go to Step 17 
17 Inspect the transmission oil fluid for a gray/white milky substance.
Does the transmission fluid contain a gray/white milky substance?		 Go to Step 21  Go to Step 27 
18 Repair or replace the leaking component. Refer to the appropriate repair.
Is the repair complete?		 Go to Step 27  -
19 Replace the coolant pressure cap.
Is the repair complete?		 Go to Step 27  -
20 Replace the heater core. Refer to Heater Core Replacement .
Is the repair complete?		 Go to Step 27  -
21
  1. Replace the radiator. Refer to Radiator Replacement (LY7 Standard Cooling) .
  2. Service the transmission. Refer to Coolant in Engine Oil .
Is the repair complete?		 Go to Step 27  -
22 Repair the engine no crank condition. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate .
Is the repair complete?		 Go to Step 27  -
23 Repair the engine overheating condition. Refer to Engine Overheating (LP1, LY7) .
Is the repair complete?		 Go to Step 27  -
24 Repair the engine internal coolant leak. Refer to Coolant in Combustion Chamber , Coolant in Engine Oil .
Is the repair complete?		 Go to Step 27  -
25 Repair the engine knock. Refer to Lower Engine Noise, Regardless of Engine Speed .
Is the repair complete?		 Go to Step 27  -
26 Repair the combustion pressure in the cooling system problem. Refer to Cylinder Leakage Test .
Is the repair complete?		 Go to Step 27  -
27 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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