Technical 1.2 cooling system issues.

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Technical 1.2 cooling system issues.

symonh2000

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Hello everyone, I am having a few issues with the cooling system on the missus Bravo 1.2

2 weeks ago I fitted a new thermostat as the one on the car was stuck open making the car run cool.

After that I bled the coolant in the way recommended on this site. The car ran at the correct temperature, heater hot, no noises from the heater etc.

However whenever the car has been for a run say over 10 miles or so, when I open the bleed screw on the top of the radiator lots of air will come out.

Also on 2 seperate occasions after parking up the car has ejected some coolant from the expansion tank.

As it was ejecting coolant I opened the lower bleed screw near the heater and a massive amount of air escaped.

What on earth is going on? The head gasket is ok (done sniff test), the fan comes in correctly and there are no obvious leaks. The car otherwise runs well and doesn't overheat.

I am really tearing my hair out on this. :cry:

It seems air is getting in somehow, but I cannot understand how that could happen if the system is pressurised.
 
Last edited:
I'm thinking air lock too.... logic suggests that as the issue started after fitting the thermostat that you should check the thermostat is bolted up correctly as a minimal water leak at the thermostat or hoses will allow air in but may go un noticed. Secondly totally re-bleed system. usually the matrix air valve is best. I usually fill the rad run engine and gently open the bleed valve until air comes out. give a drive and repeat..
 
I'm thinking air lock too.... logic suggests that as the issue started after fitting the thermostat that you should check the thermostat is bolted up correctly as a minimal water leak at the thermostat or hoses will allow air in but may go un noticed. Secondly totally re-bleed system. usually the matrix air valve is best. I usually fill the rad run engine and gently open the bleed valve until air comes out. give a drive and repeat..

Thanks for the reply mate.

It has now been ok for the rest of this week, so I am tempted just to leave it now. There have been no other issues, and there are no noises from behind the heater.

I don't have a leak from the stat housing BTW. :)

If I do get any more problems I am tempted to borrow a Vacuum pump from work and give that a go on it. :devil:
 
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