The cd manual suggests genuine Isuzu coolant (ethylene-glycol based) with no additives or inhibitors (I take this to mean rust inhibitors, but....?)

It also lists the total cooling system capacity at 8.8 litres (2.32 US gallons), although in another section of the manual it gives totals of 7.1 Litres, and 7.4 US quarts respectively, so I'd say start with the lowest number and add if necessary.

It doesn't really say whether to use a 50/50 mix, but I think that's pretty much the standard. For no more than is necessary, I always use distilled water too, especially when dealing with aluminum.

That's all I got!