Pinpoint Test F: Thermostat Coolant Leak

WARNING: This page is about a different variant/trim than selected.

NOTE:

DO NOT manipulate the thermostat housings
The thermostat assembly is a serviceable part. Individual thermostat housings are not a serviceable part.

F1: CONFIRM THE CUSTOMERS CONCERN
1. Visually inspect the thermostat assembly/housing and surrounding areas
  Is there a fresh/wet leak coming from the area the thermostat assembly/housing is located?
  
  Yes: GO to F2.
  
  No: There is no visible leak but there is dried up coolant present on the housing assembly. GO to F6.
F2: VISUAL INSPECTION OF THE THERMOSTAT CONNECTION

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1. Inspect the housing. Refer to the image. The image shows a misaligned/damaged connection. The red arrow in the image is pointing to the key and the green arrow is showing the key-way. These MUST be aligned to create the seal.
  Is the thermostat housing damaged or misaligned?
  
  Yes: Replace the thermostat assembly. Use the Removal and Installation procedures for guidance. Refer to: THERMOSTAT HOUSING (G1998228) .
  
  No: GO to F3.
F3: VERIFICATION OF THE LEAK PATH

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1. Verify there is a fresh/wet leak is coming from the connection in the image
  Is the fresh/wet leak coming from the connection in the photo?
  
  Yes: Replace the thermostat assembly due to a damaged seal inside of the connection. Use the Removal and Installation procedures for guidance. Refer to: THERMOSTAT HOUSING (G1998228)
  
  No: GO to F4.
F4: VISUAL INSPECTION OF THE THERMOSTAT END CAP

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1. Inspect the thermostat end cap, refer to the image. The thermostat end cap can be damaged or leak.
  Is there a fresh/wet leak coming from the thermostat end cap?
  
  Yes: GO to F5.
  
  No: GO to F6.
F5: THERMOSTAT END CAP LEAK
NOTE: This may not be the cause for the low coolant warning
1. Clean up the coolant from the housing
2. Perform coolant pressure test as per standard procedure Refer to: COOLING SYSTEM PRESSURE TEST .
3. If coolant pressure drop is noticed, identify the source of leak
  Is the source of the leak from the thermostat assembly?
  
  Yes: Change the thermostat ONLY if leak check shows leakage from thermostat. To confirm if the leak repeats, perform a test drive for at least 30 minutes. Inspect the thermostat housing and confirm repair. Clean any overspills or dried coolant and repeat this step if necessary.
  
  No: After finding the alternative leak path, rectify the leak path using the symptom chart and pinpoint tests found at the top of this page. Exit this pinpoint test.

F6: NO VISUAL LEAK FROM THE THERMOSTAT

NOTE:

The dried-up coolant could have been from a previous coolant spill
The dried-up coolant could be from another component that is leaking, positioned above the thermostat

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DO NOT replace the thermostat housing assembly unless it is diagnosed as the fault

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For an example of dry coolant, please refer to the images
Check for coolant leakage from coolant connections around/on top of thermostat
Check for any signs of coolant spillage in the engine compartment
Clean up all the dried-up coolant (including inside the grooves of any residual deposits)
Perform coolant pressure test as per standard procedure Refer to: COOLING SYSTEM PRESSURE TEST .
If coolant pressure drop is noticed, identify the source of leak
Is the source of the leak from the thermostat assembly?

Yes: Change the thermostat ONLY if leak check shows leakage from thermostat. To confirm if the leak repeats, perform a test drive for at least 30 minutes. Inspect the thermostat housing and confirm repair. Clean any overspills or dried coolant and repeat this step if necessary.

No: Using the symptom chart above, re-confirm the customer symptom. Inspect the rest of the coolant system for leaks. Follow the relevant pinpoint test to rectify the fault