Bleeding your coolant system

Air in the Coolant system can cause idle surging, as well as other issues. It's best to make sure you're system is fully bled of air pockets for it to function properly.

Also, If you ever flush your own coolant system, or fully drain it for any reason, chances are you're going to introduce air to the system, and Hondas don't like that. So, here is a quick step by step on how to bleed the system properly.

Bear in mind that this is a messy process, and will require about 3 rolls of paper towel, a few beers, and a half hour of so of cleanup when you're done.

What you will need:
12mm boxed end wrench
50/50 mixed coolant, get two jugs.
A funnel is a nice thing to have, as I mentioned, it can get messy.
Beers


1 Make sure car/motor is cold, and remove your radiator cap. It's crucial for your car to NOT be at operating temp; or else you will burn yourself.

2 Fill the radiator will coolant until it comes out the top.

3 Pump the lower radiator hose by squeezing it with your hands. This will get some of the bigger bubbles to come out of the radiator.

4 Now, put the front of the car up on jackstands.

5 With the radiator cap still OFF, go ahead and start car and let it idle until it reaches normal operating temperature. (You will feel the upper radiator hose getting hot. Ideally it should be almost too hot to touch, at which point the thermostat should open, and cycle coolant through the motor)

6 As the motor runs, you should see your coolant level inside the radiator going down, this is good. Just keep topping it off until the level no longer drops.

7 Once you know that coolant is cycling through the motor (you can usually feel it coming down through the lower radiator hose, and the hose will begin to get warm), put the radiator cap back on.

8 Now, with the radiator cap on, and coolant cycling through the motor, open the bleeder valve until coolant comes out. You will probably see tons of little bubbles. (If you have trouble getting the coolant/air bubbles to come out of the bleeder, just rev the engine a bit, should shoot right out.)

9 Repeat step 8 a few times until you no longer see air bubbles. It should only be a steady stream of clean coolant.

10 Tighten the bleed screw, and take the car for a ride to make sure it stays at normal operating temp, be sure there is no leaks, and also that the fan is kicking on.

That's it, go drink your beers!