changing water pump

It is not that hard to .

firstly the fan and radiator to come out.

Take all the fan belts off.

Then take off the timing belt case and the water pump is behind there.
It should take no more than 4 hours work.
If you want to get a manual for on that engine it is "Max Ellerys Vehicle Repair Manual" the book is Hilux/4 Runner 1979-1997 LN Diesel Engine Models the number of the book is EP.TH4D. If you are interested in the manual E-Mail me

Peter Clark