bleeding air from cooling system

[twofullas]

i have just changed the coolant in my 95 legacy , there seems to be a trickling noise behind the dash board . im sure there is air in the system . how do you bleed it from the system?

[lmdew]

Jack the front as high as possible. Drain the coolant and then slowly refill the system with the bleed open. I pull the top radiator hose and fill the engine, pouring fluid into that hose. I also put a radiator flush fitting in the heater hose and leave it open until fluid comes out.

 

When you've fillled the engine completely, put the radiator hose back on. Continue to fill the system, pouring fluid in the small bleeder hose until the fluid comes up to the top of the radiator fill cap.

 

Start the engine and pinch the top radiator hose open and close, it will help move any air along. When fluid starts coming out the radiator cap fitting, put the cap back on and let the engine come up to temp. Make sure the heat in on full hot for the complete process.

 

Let it cool, and check to make sure the radiator is full.

[hklaine]

My car also has a small bleed screw on the top of the radiator (passenger side).

 

-Heikki

[Setright]

Search for "coolant replacement" without the bubbles.

 

However, since you have already filled the system. Do as mentioned above. Park on a slope facing upward, 5 degrees is plenty. Let the engine COOL. Open the rad cap and bleeder if you have you one. Start the engine and idle until the fluid starts rising in the rad cap filler neck. Now, switch OFF the engine again. Hopefully, this will produce a "burb" at the cap filler neck and the level will drop again. Idle until it rises again, close the bleeder and cap.

 

Run the engine speed up to around 2000rpm for about ten seconds, either by hand in the engine or use the throttle as normal. Go for a gentle drive, and park the car level when you get back. Make sure the overflow bottle is filled to at least "max" - due to heat, it may be higher, perfectly normal.

 

Check the level in the overflow again after a long cooling period - over six hours - adjust as needed.

 

 

 

(Cabin heat on or off is irrelevant, there is always flow in the heater core.)

[Setright]

If you find that the system doesn't seem to want to loose the air, I would recommend fitting a new Genuine Subaru radiator cap. The spring and seals on the cap may be old and tired.

[twofullas]

thanks i wil try all these things this weekend . i live in new zealand youve all been a great helpi

If you find that the system doesn't seem to want to loose the air, I would recommend fitting a new Genuine Subaru radiator cap. The spring and seals on the cap may be old and tired.