How do you properly bleed the cooling system?

[Castel]

Hi all,

I've looked for a clear description on how to bleed the air out of the system but haven't been able to find it. Can you guys tell me how to do it in my car? Thanks!

[ganseg]

There is a bleeder screw up near the radiator cap. You loosen it and run the car till a stream of water comes spraying out the side. Then you tighten it. I usually go out for a few miles after that to totally warm it up, then check the level when cool.

[havnfun328]

I watched my indy mechanic do it. With the engine cold, remove the bleeder screw. With the engine off, but with Ignition key in position 2 and climate control all the way to hot, *slowly* poor coolant into the expansion tank until it comes out the bleed hole. Replace screw and radiator cap.

That was it. He said to check it when cold after driving a couple of days and refill as necessary, but I never had to add any.

[bimmerboy328i]

Fill the cooling system up until the coolant coming out of the bleeder screw hole is free of air bubbles. Put bleeder screw on and leave resevoir cap off still. Start the car with the heater on 90 and in the defrost position. Let it get to operating temperature. If coolant starts to pour out, cap it but make sure that you have heat. If you do not have heat have someone give some revs and slowly open the bleeder screw to let the air bubbles out and until have coolant coming out free of air bubbles.once you have bled it and made sure you have good heat, remove the resevoir cap, have someone give you about 3k in RPMs and top it off.

[srcstc]

http://www.bmw325i.net/maint_coolant_change.shtml

[easport]

srcstc (or anybody else that can help me), I looked at the link that was sent and I have one question, as the second step was to "Turn the ignition to the "ON" position and set the heater controls for 91 degrees" do I need to leave it in ON position when I drain the coolant or only when I refill the coolant and bleed the cooling system to make sure that no air is trapped in there? My inclination was to leave it in ON when I refill and bleed, but I just want to make sure. Thanks in advance.

[dblmikeusa1]

yes, leave it on so the system is open

[easport]

Leave it on all the time (during draining and refilling/bleeding) or only during refilling and bleeding? Thanks.