How To Bleed The Coolant System On A VW Group Car (Coolant Expansion Tank System), by Despair Repair on YouTube. 9 min 51 s.
- Video length
- 9 min 51 s
- Time to do it
- 30 minutes
- Difficulty
- Easy
- Steps
- 7
What you need
Steps
Park the car on level ground and let the engine cool fully, at least an hour. Never open the expansion tank cap while the engine is hot.
Open the bonnet and fill the expansion tank with the correct coolant mix up to the max mark. Keep a funnel and a rag handy for spills.
Leave the cap off. Start the engine and set the heater to full hot with the fan on low so coolant flows through the heater matrix.
Let the engine idle for 10 to 15 minutes until the radiator fan cuts in and out. Watch the tank and top up as the level drops.
Hold the revs at about 2000 rpm for 30 seconds, a few times. This pushes trapped air through the system and out of the open tank.
Squeeze the radiator and heater hoses by hand to shift air pockets. Refit the cap once bubbles stop rising and the level stays steady.
Take a 10 minute drive with the heater on hot, then let the engine cool completely and recheck the level. Top up to the max mark if needed.
Tips and common mistakes
Use the coolant spec listed in your owner's manual, such as G12evo or G13, and never mix different types.
If the heater still blows cold after bleeding, air is left in the matrix. Repeat the idle and rev procedure.
A vacuum coolant filler pulls most of the air out before you start and saves time on refills.
Questions
How do I know all the air is out?
The level in the expansion tank stops dropping, no bubbles rise with the cap off, and the heater blows hot at idle. Check again after a drive once the engine is cold.
Can I drive with air trapped in the cooling system?
No. Air pockets create hot spots and can warp the head or blow the head gasket. Bleed the system before driving normally.
Do I need a vacuum filler to do this?
No. The expansion tank method works on most VW Group cars. A vacuum filler is just faster and cleaner.
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.
