Cooling system question

[joules]

What is the bottle, that is connected to the radiator overspil hose, at the back of the engine actually for. I have only just started working on capris hense the lack of knoledge. Looking at photograps and the evidence of a filler cap on the top of the bottle and a min and max morks, i wonder `do I fill the thing with water and anti-freeze?????

Thanks for your help

[guitarswet]

The bottle you are referring to is called an expansion tank - all modern cars have these fitted. The tank allows water from the cooling system to enter and leave the tank as the pressure increases because the water gets hot. You should find that if you remove the radiator cap on the top of the radiator the water should be right up to the very top. If not you should fill the radiator with 50% water 50% antifreeze to the top and replace the cap. Now fill the expansion tank so that the water is just above the minimum mark. After long journey you will see that the water in the expansion tank has risen, probably up near to the maximum mark, and it will drop slowly again as the engine cools.

If you drain the cooling system, you will need to replace the water using the radiator cap, not the expansion tank. However you can top up with small amounts of coolant using the tank. If your car appears to be consuming water then you either have a leaking pipe or radiator or you have a problem with the cylinder head gasket!

I have not had to put any water in my Capri for twelve months now.