thanks for the advice, distilled water , no coolant, para dissolved lhat ng rust sa engine and radiator , copper tubes naman ata ang radiator so no problem, I worry about sa ibang water fittings sa engine bka me sacrificial anode pa na bibigay (zinc material). This design of the engine I thought it will last as long as properly maintained pero me weak points rn talaga.

the car is 97k odo first owned, rarely used FC is a bit high ,low of 9 km/ltr, extreme traffic 7 km/ltr, nasanay kasi ng 12 km/ltr sa diesel