vt how to bleed the air from the cooling system ?

[Brett_jjj]

I just think that some people must try to fill the radiator with the engine turned off instead of idling.If the engine isnt running,theres no vacuum supplied to the heater tap which holds the tap open,and without the tap open,air is trapped in the heater unit and its hoses etc.Or maybe the heater tap is faulty and doesnt open which would cause the same thing to happen.So will filling the radiator with the car facing downhill instead of uphill.I thought I would have had trouble with it now after doing quite a few coolant changes etc if trapped air really were a big problem for this engine.Some of the old flathead V8s years ago were really bad for this problem.They would suffer from it badly with hot spots in the heads where the tops of the water jackets would trap air.Ive read in some old hotrod mags that some people came up with the idea of using compressed air to pressurise the water in the radiator to force out the trapped air in the engine coolant passages...

 

[Perish Hose]

This is how I have bled both mine and a friends, you should also make sure the heater tap is turned on and depending on how the bottle fits into the top of th eradiator you may need to either pinch off the overflow hose or take it out of the overflow and hold it above the top of the coke bottle as the coolant may flow into the overflow as well.

Why would the heater tap be turned off? Isn't it always on? Do you mean you turn the heater on inside the car?

The reason I ask is I bled my cooling system as per the instructions here - it doesn't overheat. However when I start the car I can here a gurgling behind the steering wheel. Is tis normal?

 

[edals]

Why would the heater tap be turned off? Isn't it always on? Do you mean you turn the heater on inside the car?

The reason I ask is I bled my cooling system as per the instructions here - it doesn't overheat. However when I start the car I can here a gurgling behind the steering wheel. Is tis normal?

The heater tap is for the heater in the car. To bleed the system it must be turned on full hot. The gurgling sound under the dash is air trapped in the system, so it's not normal and needs to be bled again.

 

[Perish Hose]

Here's another question.
Radiator cap off.
Engine getting hot.
Bubbles coming out of radiator cap.
? Is that a blown head gasket ?

 

[Turtl3]

if they are small bubbles the look similar to fizzy drink they yeah...more than likely the head gasket. check your oil to see if its milky

 

[devilly]

if bubbles ,and oil in coolant and milky dipstick and loss of power then look at head gasket.bubbles i found is 8/10 times the water pump calcium build up so it doesn't go through properly.

 

[edals]

Get a pressure test on the cooling system and a compression test. Stop guessing and diagnose correctly. Ecotecs very rarely blow head gaskets.

 

[amg]

Mines been blowing bubbles in the coolant for over 10 years, definitely not a blown head gasket as this 6 pot still goes like stink (although a bit tired and blows a little smoke in protest when pushed).

 

[Jxfwsf]

Unless it's bled properly the pump will aerate the cooling system, bleed it properly.

 

[nitrofan]

Sorry to bump an old thread, but when using the coke bottle method once youve (hopefully) got the air out and closed the bleed valve what do you do with bottle? Just pull it away and quickly put the radiator cap on?