Radiators

Distilled water is better, this lessens the chance of corrosion.

Add 4 lts of a good concentrated anti freeze anti boil as well.

Can you use tap water? Yes! unless its water from Adelaide you wouldn't do anything with that. LOL

Cheers Steve.

All alloy engines should use distilled water, most manufacturers will state this as they have no idea what the mineral content of your water is.

Alloy head/ cast iron block, why not used distilled water as it is not dear to buy.

Iron block/iron head, again distilled is cheap but hell, tap water is fine.

Good antifreeze/inhibitor, Afloc 2000 or Toyota longlife are great but they don't mix with the green glycol products.

If you stick with what the manufacture recommends, you can't go wrong.

All spelling/grammer mistakes in this post can be blamed on the Bunderburg distilling company.

The Ape

CraigB
There are a couple of issues here.
1: Demineralised water is the only real choice. Sydney tap water contains
both high levels of Manganese, and elevated Iron as well. Considering
the cost of the demineralised water being so low, you should not really be
using anything else, particularly as you want to minimise the presence of
dissolved metal ions in the system.
2: The Landcruiser cooling system is set up for OAT [Organic Acid
Technology] coolants so using conventional chemical based coolants is not
advisable. The chemical interaction between the residual amount of coolant
after draining the system [about 1 litre] and any non OAT system causes
the alternate chemistry to be degraded prematurely, reducing the life
the corrosion inhibitors, particularly the Aluminium and Iron inhibitors.

Craig,
Yes you should use the Toyota LLC at 50% in demineralised water.