Cooling System Operational Test
COOLING SYSTEM OPERATIONAL TESTWITH 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)
- Drive belts are intact and properly tensioned. Attempt to turn the water pump pulley by hand, if the pulley spins inside of the belt it is too loose.
- 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.
- Re-check expansion tank level. If coolant begins to bubble into the expansion tank after turning off the engine, pressure check the radiator cap and verify it will hold the rated pressure.