Have a look at this link from the web, hope it sheds some light on your problem. http://www.cavweb-forums.co.uk/showthread.php?p=1920469
no will probably se the sensor on the bottom of the header tank
2005 fiesta header tank fitting instructions
2005 fiesta header tank fitting instructions
remove hose from rad to expantion tank, at tank end, fill rad through hose connect and start up top up header tank.
it might not have on so in this case just take the bottom radiator hose off and drain it out that way, remember to take the header tank pressure cap off
If you are getting water in the fuel filter, it is coming from your fuel tank. You will need to remove and clean the tank.
Blown head gasket or air lock in cooling system.
how do I replace my 2005 fiesta expansion header tank
in the fuel tank
No. Do not put unleaded gas in a diesel tank.
When your Astra diesel runs out of fuel, air can enter the fuel system, leading to a loss of fuel pressure and making it difficult for the engine to start. Additionally, diesel engines rely on a specific fuel injection process, and without fuel, the injectors can become clogged or air-bound. To resolve this, you'll need to prime the fuel system by refilling the tank and possibly bleeding the fuel lines to remove any trapped air.
in the tank