Ahh right, well i'll try that tomorrow after work then! Cheers for the help :thumbs:

You only need to leave the cap off until the coolant has circulated around the system. Then put it back on, run the engine, makes sure all hoses get hot and the fan should come on.

I know that bit, but surely if you have to leave the cap off to bleed the system and to wait for it to get up to temperature it's going to boil. But don't i need the fan to kick in with the cap off the expansion tank?

the coolant will boil if you leave the cap off. The cooling system is under pressure and when water/coolant is under pressure it wont boil. If you remove the cap it is no longer under pressure and therefore will boil.

Right, i've put a new coolant pipe on a Mk5 Astra 1.6 16V.

Is there a bleed screw on the system anywhere? I couldn't find one and i was advised there wasn't one as well

So i filled up the water, left the expansion tank cap off and started the engine. Waited for it to get warm and for both pipes going to the radiator to get warm. Now my problem... The water in the expansion tank started to boil, the fan never kicked in and it was starting to try boiling out of the expansion tank. These Astra's don't have a temperature gauge so i have no idea if the engines over heating? If the fan doesn't work? If i've messed up bleeding the system? :lol:

Someone please enlighten me on this please! :)