I am sure Richard is right it is flammable providing the engines okay with a good water pump fan and radiator there’s no reason for it to overheat I just use distilled water with a 50-50 mix of blue Antifreeze I do have a 82° thermostat restorations Upgraded water pump and 16 inch electric fan behind the rad it does seem very efficient
How about putting it on eBay with a £1000 start price with good pictures you may find you get two or three bidders and it could surprise you what it may make