How to Bleed Air From a Radiator

The radiator is an important part of the engine.

The radiator plays an integral role in the overall health of your engine. Due to internal combustion, the engine builds up a tremendous amount of heat. The radiator provides a path for the engine coolant to flow through, thus circulating the heat from the engine, so that the engine doesn't overheat. Air bubbles can sometimes get trapped in the radiator; this can impede its function, so the air needs to be removed. Bleeding air from a radiator can be done quickly by any car owner.

Things You'll Need

• Coolant
• Water

Instructions

1. Open the radiator and fill it to the top with coolant and water in a 50/50 combination. Water is not needed if your coolant already comes premixed. Leave the radiator cap off. The engine must be cool when you do this.

2. Fill the coolant reservoir tank all the way to the top with the same blend of coolant and water. (Likewise, water is not needed if the coolant is premixed with it.) Put the cap back on it.

3. Turn on the engine and allow it to run while the radiator cap remains off. When the coolant level in the radiator suddenly drops or bubbles raise to the surface, air has been "burped out."

4. Monitor the engine temperature while the engine is running. If the gauge goes into the red or if a engine temperature warning light turns on, shut the engine off immediately and allow it to cool.

5. Refill the radiator and tighten the cap back on.

Tips & Warnings

• Never remove the radiator cap when the engine is hot. The hot radiator fluid can shoot out of the radiator and cause severe burns. Always wait for the engine to be cool before adding coolant or removing the cap.

References

• Mileposts Garage: Trapped Air in Cooling System
• Almohandes.org: How to Burp Your Car's Cooling System