When I started on the DIY water cooling idea my current car, a 1986 Toyota Celica, was getting scrapped (shame to see her go).
I started playing around with things to see what I could salvage, now the main radiator was HUGE - therefore not an option - although passive cooling sounded nice, the main objective of the future system then, was noiseless operation & looks, the objective has obviously changed since ;)
Aha, what do we have here? An Oil cooler !!! So some cuts & scuffs later I managed to pull this out, still with oil inside - nice size, slightly bigger than two 120mm fans put next to each other... Hours later I had a look on eBay again, seeing maybe there were better alternatives, now how lucky was I - I spotted a 'similar' looking radiator, won for £5 and upon receipt it turned out to be identical to the one from my car! – Again, with fresh oil in the lines (a nightmare to flush out!)“oooh aluminium - no metal mixing!”So - 2 radiators - cost: £5
I purchased other essential bits, like the pump, an Eheim for €30, 3 meters of 1/2" tubing, more barbs, 6x 120mm fans, jubilee clips, and of course some WaterWetter ;)...