Recently bought an '02 Lancaster EZ30D for cheap, partially because of a slight radiator leak and RCG leak. I aim to replace the radiator as a headgasket failure prevention mechanism for summer/towing/inevitable city driving in Wellington. Coolant temp stays fine on the open road, even in 26+ degrees however once it gets above usual running temp (just below halfway) it is very hard to bring back down and very prone to increasing towards the 'wincing' area of the gauge. Hoping this is happening because of both an old, inefficient radiator and a persistent leak, meaning the coolant system contents are probably a good deal water at this point, so not the best for keeping the boat cool.
I will look for a second hand (non-leaking) OEM radiator or grab this one off TradeMe: https://www.trademe.co.nz/a/motors/car-parts-accessories/subaru/radiators/listing/3375109974?bof=mqz1V7S1
Any input in terms of suggestions for new radiator, coolant choices, tips for replacing/bleeding the system are much appreciated. Especially any input re the above linked unit.