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Bleeding cooling systems
zilspeed - 12/7/05 at 05:39 PM

As per the title

Now that I finally have the head back on the engine in the GTM I've forgotten the exact method of how I bled the cooling system.

Can anyone remember before I put an axe through the little fecker ?

I seem to remember it involved blowing into the header tank. I'll wait until it's dark and go out and have a go - when nobody can see me.

P.S. well chuffed at actually getting it all back together and running.


tadltd - 12/7/05 at 08:53 PM

Hi Zil,

Cooling system fill & degas method:

1) Mix plenty of coolant + water (50:50), at least 10 litres.
2) With engine cold, fill the bottle (header tank) to max (and repeat as coolant is drawn into the system)
3) Once coolant ceases to be drawn out of bottle, start the engine, leaving the cap OFF the bottle.
4) Run the engine until the fan switches on 3 times, then switch off.
5) Let engine cool (leave cap OFF)
6) Top up the bottle to 'max' mark, put cap on, and start engine.
7) Run engine until fan switches on 3 times, then switch off and let engine cool.
8) Coolant should return to max level. If it is below, then top up to max again and check for leaks. If it is above, air is still in the system, so repeat steps 2 - 7.

DO NOT BLOW INTO BOTTLE!!

[Edited on 12/7/05 by tadltd]


zilspeed - 12/7/05 at 09:05 PM

Steve


I gave up earlier this afternoon. I figured I had made very good progress up to that point. I will now exhibit a huge amount of patience and make sure that there is no air in the system before even thinking about going anywhere in the car.

P.S. Rad stone cold, so no chance of the fan coming on.

I'll get there


NS Dev - 12/7/05 at 09:16 PM

stating the obvious as I know that you know what you are trying to do, but on systems that I have put together, I have always made sure that I have some sort of removable bung at the top of any place that can trap air in the pipework. A little M5 thread tapped into the pipe (assuming it is alloy etc) will do, fill until coolant comes out then replace the screw with a dab of silicone on it.

Short of that, loosen any hose clamps near the top of hose runs and let coolant p155 out until there's no air left, then tighten them up while it's still p155ing out.


tadltd - 12/7/05 at 09:25 PM

The method I listed above was one we used at Ford and was very effective at removing air from the cooling system of any car (without too much pi55ing about!)


NS Dev - 12/7/05 at 09:30 PM

sorry, should have said, that is exactly how I fill cooling systems as well!! Sorry mate!

On things like my grasser though the pipe runs are awkward and it still tends to get airlocks, so I have the bleed screws to get water through the system as much as possible prior to starting and running for a bit with the cap off.


johnjulie - 13/7/05 at 07:55 PM

Quite a few modern cars have bleed valves fitted as standard in the heater hoses etc. It would be easy to fit one of those.
Cheers J&J