How to Properly Bleed Engine Cooling System by yourself, by 1A Auto: Repair Tips & Secrets Only Mechanics Know on YouTube. 2 min 32 s.
- Video length
- 2 min 32 s
- Time to do it
- 30 minutes
- Difficulty
- Easy
- Steps
- 9
What you need
Steps
Park on level ground and let the engine cool completely, at least an hour after driving. Never open the radiator cap on a hot engine.
Put on safety glasses and gloves, then place a spill tray under the radiator. Lay a rag around the cap to catch drips.
Remove the radiator cap and check the coolant level. It should sit just below the filler neck.
Fit the funnel into the radiator neck and pour in premixed coolant until the level reaches the base of the neck. Fill the overflow reservoir to its cold mark.
Start the engine and turn the heater to full hot with the fan on low. This opens the heater valve so coolant flows through the core.
Let the engine idle and watch the radiator neck. Bubbles will rise as trapped air escapes. Top up with coolant as the level drops.
Squeeze the upper radiator hose a few times with a gloved hand to push air pockets out. Keep the funnel filled so air is not sucked back in.
Once the bubbles stop and the level holds steady, switch off the engine. Fit the cap tightly and top up the overflow reservoir to the cold line.
Run the engine until the radiator fan cycles on, then let it cool and recheck the radiator and reservoir levels.
Tips and common mistakes
Keep the funnel partly filled during the whole job so air cannot flow back into the radiator.
Coolant is toxic to pets and children, so soak up spills and take old coolant to a recycling center.
If the heater still blows cold after bleeding, air is probably still trapped and you need to repeat the process.
Use the coolant type listed in your owner's manual, and mix concentrate with water before pouring it in.
Questions
How do I know if there is air in my cooling system?
Common signs are a heater that blows cold, a temperature gauge that keeps climbing, gurgling behind the dash, and a coolant level that drops with no visible leak.
Can I bleed the cooling system without a funnel?
Yes, but a funnel keeps the coolant level above the radiator neck and stops air being pulled back in. A spill-free funnel kit makes the job cleaner.
Do I need to run the engine with the radiator cap off?
Yes, for a few minutes at idle. That lets the thermostat open and pushes trapped air up and out of the open radiator neck.
This guide was drafted from the video's details and general task knowledge. It has not been checked against the full video. Check the video and relevant product instructions before following a procedure. Report a correction.
