bleeding air from cooling system, how?
Thread Starter
Instructor
Joined: Jul 2003
Posts: 108
Likes: 0
From: Sacramento california
bleeding air from cooling system, how?
i,ve completed serviceing my cooling system(replaced radiator) now how do i install the new coolant without creating air pockets,or better yet how do you bleed the air from the cooling system?
thanks boonie
thanks boonie
Team Owner
Joined: Mar 2000
Posts: 83,381
Likes: 87
From: Boston, MA
Re: bleeding air from cooling system, how? (boonie2)
With the cap off fill it as much as you can with the car idling. Once the temp reaches the opening temp for the thermostat you'll see the coolant fall low again so add more. One the thermostat is open also have someone hold the RPM around 2000 and fill until it is up at the neck and you see no air bubbles. Replace the cap and THEN let the car return to idle. You might have to do this a few times.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: bleeding air from cooling system, how? (boonie2)
You don't create an air pocket the engine sits higher than the radiator, GM did it for you. Pour your coolant into the filler, start and let the engine idle until it gets to the opening temp of your thermostat. Race engine by pulling on the throttle cable stop on the front of the MAF, this will make the coolant flow and the coolant level will drop looking into the filler. Fill to the neck and install the radiator cap. Fill the overflow 1/2 way. It's Miller time. :D
Melting Slicks
Joined: Jun 2002
Posts: 2,168
Likes: 16
From: Phoenix AZ
Re: bleeding air from cooling system, how? (jfb)
It also helps to park the car with the front slightly higher than the rear, such as in a sloped driveway. Don't waste any time topping the radiator off and putting the cap back on once the thermostat opens, it doesn't take long after that before the system reaches boiling temp and coolant gushes out all over your car.
Instructor
Joined: Apr 2003
Posts: 224
Likes: 0
From: Gilbert Arizona
Re: bleeding air from cooling system, how? (jfb)
From what I can tell, the later C4's highest point in the system is the fill point (the plastic reservoir closer to the firewall on the passenger side). So, would trapped air be an issue with that design?
FWIW, I've seen this newer design in the yrs '91 and newer. My '89 does not have it, but not sure about model yr '90.
[Modified by SkunkCar, 6:54 PM 8/1/2003]
FWIW, I've seen this newer design in the yrs '91 and newer. My '89 does not have it, but not sure about model yr '90.
[Modified by SkunkCar, 6:54 PM 8/1/2003]
Burning Brakes
Joined: Jul 2002
Posts: 871
Likes: 0
From: Costa Mesa CA
Re: bleeding air from cooling system, how? (boonie2)
Yeah, do it the way vetracer says. Other than drilling a small hole in your thermo or running without it (the way I do) there is no other sure way of not trapping air bubbles. Elevate the radiator well above the engine.
Drifting
Joined: Jun 2001
Posts: 1,625
Likes: 1
From: Zagreb, Croatia
Re: bleeding air from cooling system, how? (BIG JIM 54)
Never had any problem with air in the cooling system.
I allways just fill to max. level ( reservoir on passenger side ),
start the engine and let the thermostat open. Turn off the engine and let it
cool down. Check the fluid level and add some if necessary.
But then again I have '90 and it looks like the older years have
different cooling system.
I allways just fill to max. level ( reservoir on passenger side ),
start the engine and let the thermostat open. Turn off the engine and let it
cool down. Check the fluid level and add some if necessary.
But then again I have '90 and it looks like the older years have
different cooling system.
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Racer
Joined: Jul 2002
Posts: 275
Likes: 13
From: South Bend, Indiana
Re: bleeding air from cooling system, how? (boonie2)
This might sound hokey to some, but on my 88 I installed a Prestone flush kit at the highest point of the heater hose. This is where I now bleed the air and top off the system. Takes a fraction of the time.
