Component Tests and General Diagnostics

COOLING SYSTEM OPERATIONAL TEST

WITH THE ENGINE COLD
- Remove the radiator cap/expansion tank cap and check the coolant level, refill as necessary.
- Pressurize the cooling system and check for leaks
- Inspect:
- Radiator cooling fins are not blocked with debris (bugs, leaves, dirt)
- Oil is not contaminated with coolant.
- Check bottom side of oil filler cap, this is where coolant contamination often accumulates first.
- Check oil with dip stick.

NOTE: Oil contaminated with coolant or water will have a creamy, light brown color.

- Coolant temperature switches and sensors are connected properly.
- Radiator hoses are not pinched.

START ENGINE AND ALLOW TO WARM UP

CAUTION: Observe the temperature gauges, warning lights, and expansion tank. Immediately turn off the engine if signs of overheating occur.

- Check for coolant leaks.







- Verify the thermostat opens and operates properly, see drawing.
- After the thermostat opens, verify electric fan operation.

NOTE: The cooling fan should come on after the thermostat opens but before the engine overheats.

- Check the exhaust for white smoke (evidence of coolant entering the combustion chamber)
- Turn on the front windshield defroster and check for:
- Coolant smell.
- Windshield becomes fogged.

NOTE: These are both symptoms of a heater core leak.

- Check coolant expansion tank level
- Stop Engine.

WITH THE ENGINE "OFF"
- Check for coolant leaks.




- Perform chemical combustion leak check.
- Re-check oil for coolant contamination.