How much radiator coolant should I use ?
Engine is 2.0 zetec black top.

40/60 split antifreeze 40/water/60

So how many litres cause I don't know how many litres it holds to do 40/60 split

Virtually impossible to say accurately as your system is a one off. Probably 4-5lt total. Best way is to mix one litre at a time and pour it in, then repeat until full and keep a record of the total quantity for future reference.

Nearly all the coolant sold now is pre-mix anyway which is a bit of a con as they charge almost the same price but might be a good if you live in a hard water area.
Only place I found pink OAT antifreeze concentrate at a good price this year was. B&M Bargain Store.
Always use OAT type coolants they last for 5 years plus provided the concentration is kept up.
If you buy concentrate don't get too worried about the mixture ratio anything between 25% and 66% antifreeze will be fine but about 50% is ideal.
If the concentration is at the lower end it is advisable to freshen up with a little fresh concentrate top up every year.
Over 60% antifreeze to water the frost protection slowly starts to fall.
20% antifreeze to water will be adequate for a bad UK winter but not ideal.

[Edited on 25/3/14 by britishtrident]

[Edited on 25/3/14 by britishtrident]

Halfrauds sell pink OAT concentrate off the shelf, 24£ per 4 litres, bought some 2 weeks ago as nowhere else around. Ouch.

All done. Got the stuff from GSF as they are local.
Worked out around 5 litres total so did 2 litres antifreeze and 3 litres water.