Engine Overheating

2006 Pontiac G6 GTP, 2D Coupe, StandardSECTION Engine Overheating
WARNING: This page is about a different car, the 2005 Saturn L300. However, it is still accessible from the selected car via links, so may be relevant.
Engine Overheating

Step Action Value(s) Yes No
DEFINITION: The engine temperature lamp comes on and stays on, or temperature gage shows hot, or coolant overflows from the surge tank onto the ground while the engine is running.
1 Check for a loss of coolant. Refer to Loss of Coolant .
Is there a loss of coolant?
- Go to Step 2  Go to Step 3 
2 Fill the system to the specified level. Refer to Draining and Filling Cooling System .
Does the engine still overheat?
- Go to Step 3  System OK
3 Check for kinked or pinched surge tank hoses, especially at the radiator.
Are any surge tank hoses kinked or pinched?
- Go to Step 4  Go to Step 5 
4
  1. Relieve any kinks by rerouting the hoses.
  2. Replace the hoses if necessary.
Does the engine still overheat?
- Go to Step 5  System OK
5 Check for loose, missing or damaged radiator air seals or deflectors.
Are there any loose, missing or damaged radiator air seals or deflectors?
- Go to Step 6  Go to Step 7 
6 Repair or replace any loose, missing or damaged radiator air seals or deflectors.
Does the engine still overheat?
- Go to Step 7  System OK
7 Check the coolant concentration.
Does the coolant concentration test correctly?
- Go to Step 9  Go to Step 8 
8 Replace the coolant if necessary. Refer to Draining and Filling Cooling System .
Does the engine still overheat?
- Go to Step 9  System OK
9
IMPORTANT: Use the correct pressure cap.
Check the system for loss of pressure.Is there a loss of pressure?
- Go to Step 10  Go to Step 11 
10 Repair any leaks as necessary.
Does the engine still overheat?
- Go to Step 11  System OK
11 Check for a faulty engine coolant temperature sensor (ECT).
Is the engine coolant temperature sensor faulty?
- Go to Step 12  Go to Step 13 
12 Replace the ECT. Refer to Engine Coolant Temperature (ECT) Sensor Replacement in Engine Controls - 3.0L (L81).
Does the engine still overheat?
- Go to Step 13  System OK
13 Check the radiator for any air flow obstructions or bent fins.
Is there any airflow obstruction or bent fins?
- Go to Step 14  Go to Step 15 
14
  1. Remove or relocate add-on parts that block air flow to the radiator.
  2. Clean any debris from the radiator core.
Does the engine still overheat?
- Go to Step 15  System OK
15 Check for any blocked cooling system passages.
Are there any blocked cooling system passages?
- Go to Step 16  Go to Step 17 
16
  1. Remove any obstruction.
  2. Flush the cooling system as required. Refer to Coolant System Flushing .
  3. Refill the coolant. Refer to Draining and Filling Cooling System .
Does the engine still overheat?
- Go to Step 17  System OK
17 Check for an inoperative cooling fan.
Is the cooling fan inoperative?
- Go to Step 18  Go to Step 19 
18 Replace the cooling fan. Refer to Cooling Fan Replacement - Electric (L81)  or Cooling Fan Replacement - Electric (Pusher Fan) .
Does the engine still overheat?
- Go to Step 19  System OK
19 Check for a thermostat that is stuck closed.
Is the thermostat stuck closed?
- Go to Step 20  Go to Step 21 
20 Replace the thermostat. Refer to Thermostat Replacement .
Does the engine still overheat?
- Go to Step 21  System OK
21 Check for a faulty water pump. The impeller blades may be eroded or broken.
Is the water pump faulty?
- Go to Step 22  -
22 Replace the water pump. Refer to Water Pump Replacement (L81) .
Does the engine still overheat?
- - System OK
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.