Hi there, last night I replaced the cam belts, water pump and alternator on my 04 zetec 1.6.. 

however, after filling the system with coolant I can't seem to be able to get air out of the system. The right hand side of the radiator is hot when the engine is run and the lower left is clock cold. Squeezing the hoses whilst it is running even till it is boiling over doesn't seem to be able to get the air out.

also the expansion bottle is only a couple of months old, when the coolant starts boiling the cap is leaking and the bottle seems to be leaking from either the seams or around the feed in pipe.. have I fuckrd it letting it boil over? 

I'm guessing il need a new bottle? Will this leak be the reason why I can't seem to bleed the system? 

A little wisdom would help a lot, thanks in advance :)

Filling and bleeding the coolant system on this type of engine can be a real nightmare.

By filling the coolant system the usual way through the coolant reservoir a certain amount of air gets trapped inside the coolant system. This air will not be purged out of the system during normal operation. The air inside the coolant system can even prevent the thermostat from opening and in worst case scenario can even cause engine damage.

To prevent air to get trapped into the coolant system the coolant system needs to be vacuum filled. This method is also prescribed by Ford.

As an alternative you can try to raise the front of the car about 20 to 30 cm and let the engine run at about 2000 RPM until the engine reaches the normal operating temperature and the thermostat opens. when doing this you should look careful for the coolant level because at some point when the air is purged out of the system the coolant level will drop quite a bit.

 

The coolant reservoir cap has a spring operated valve which opens when the pressure inside the coolant system becomes too high. When the coolant is boiling (the boiling point of coolant is about 135 degees Clelsius) the pressure inside the coolant system will become too high and opens the valve inside the coolant reservoir cap. When this happens the coolant will be drained through the drain pipe of the reservoir. When the reservoir does not have a drain pipe the coolant will leak between the cap and the reservoir.

Thanks for the help I have done as you said and it went down a little but and all the hoses are hot to the touch and it doesn't seem to be boiling over! Thanks!

I have found what seems to be some sort of air leak coming from the right hand side of the engine under the airbox now, I can't feel any air blowing but I can definitely hear it. Is there anything in particular I can check?