Cooling – Coolant Drain, Fill, and Bleed

What this guide covers:

How to drain your coolant, fill it up with new coolant, and properly bleed all air out of the cooling system.

What you will need:

  • 4 gallons of new coolant (prediluted recommended)
  • Drain pan or bucket with at least a 3 gallon capacity
  • Flathead screwdriver
  • 12mm socket or wrench
  • 5/16″ ID vinyl tubing
  • Jack and jackstands


  • Lisle Spill-Free Funnel (extremely helpful for bleeding coolant)

Service Manual Information


coolant diagram

A diagram of the coolant system in the AW11.


coolant capacity

The coolant capacity of the AW11 based on transmission type and whether the heater core is in.

Official Steps:




My Steps

  1. Gather all of your materials and get the car up on jack stands:Jpeg
  2. Put the temperature control lever on the hottest setting (85):

    Temperature Control Panel
    Temperature Control Panel
  3. Remove the battery in the engine bay and the cover in the frunk, and locate the three coolant air bleeder valves (don’t even worry about the engine coolant drain valve it’s behind the AC compressor and is a huge pain in the ass to get to):
    Thermostat Air Bleeder Valve (below battery in engine bay).
    Heater Core Air Bleeder Valve (behind frunk cover)

    Radiator Air Bleeder Valve (see the nipple on the far right of the radiator)
  4. Connect the 5/16″ ID vinyl tubing to all three air bleeder valves, suspend them with zip ties or whatever else you want to use, and open the valves by twisting them counter-clockwise:
    Heater Core

  5. Get your drain pan under the car, connect vinyl tubing to the radiator drain petcock, drain the coolant out of the radiator, and drain the coolant out of the two hard metal coolant lines running below the bottom of the car (12mm bolts):
    Radiator Draining
    Radiator Draining

    Metal Lines Draining
    Metal Lines Draining
  6. Put the bolts back on the two hard metal coolant lines under the car, and close the drain petcock on the radiator.
  7. Open up the radiator cap in the engine bay and fill it up with the new coolant (you’ll only need about 3 gallons, but I recommend getting an extra in case something goes wrong). If you have the Lisle spill free funnel connect it to where the radiator cap goes (using the cap and connector labeled with a “B”):
    Lisle Spill-Free Funnel
    Lisle Spill-Free Funnel

    Heater Core and Radiator
    Heater Core and Radiator
  8. Start the car and let it run on its own until the temperature gauge on the dashboard shows it has reached the normal operating temperature (about 180ºF).
  9. Intermittently rev the car up to 3K RPMs and then let it go back to idle. As you do this you should see air bubbles leaving the radiator and heater core:
    Coolant Lines as seen from Driver's Seat
    Coolant Lines as seen from Driver’s Seat

    Air Bubbles coming out of Thermostat Housing
    Air Bubbles coming out of Thermostat Housing
  10. Keep running the vehicle until the radiator fans kick on (about five minutes or so). If the radiator fans don’t kick on, check the radiator and touch it very carefully — if it’s not warm then something is wrong with the thermostat and you’ll likely need to replace it.
  11. With the car still running, close the heater core’s air bleeder valve and the thermostat housing’s air bleeder valve. Rev the car again like we did before and watch for more bubbles to come out of the radiator’s air bleeder valve.
  12. After about a minute or so, shut the car off and let the it cool down.
  13. Close the radiator’s air bleeder valve and remove the Lisle spill-free funnel (put the plunger in it and then lifting the thing all the way off). You can pour the excess coolant into the coolant reservoir bottle, or back into one of the new coolant jugs.
  14. Put the radiator cap back on, get the car off the jack stands, and go for a test drive!
  15. If everything checks out, bring your used coolant to a recycle center that takes it. Used coolant should never be drained anywhere else because it is highly toxic and can kill people and animals.

Things to watch out for:

  • If it seems like you have a crapton of air bubbles that keeps coming out, it’s the coolant boiling and not a lot of trapped air. Check that the thermostat is opening by carefully touching your radiator to make sure it’s getting warm. If the radiator is not getting warm then the thermostat is likely not opening or there is some other blockage. Drain the coolant and check / replace the thermostat if this happens to you.
  • Wear goggles when working around coolant to prevent getting it in your eye. You might look a bit silly and overly safe, but I can guarantee you that looking silly is much better than running your eye under water for 20 minutes and sitting in a waiting room hoping your eyeball isn’t fubar’d.
  • Be very careful with how you store coolant. It’s highly toxic to humans and animals, and the sweet taste makes it very easy for house pets and wild animals to come drink it and die. Don’t put coolant in any sports drink bottles or open containers. Also, do not drain your coolant down the driveway / gutter, or toss it into the garbage can. Please bring your coolant to a place that accepts used coolant for recycling.


    1. I’ve got one, but shipping from the US would me expensive. Best bet would be to try Facebook MR2 groups and eBay.

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