I have a 1998 4.5l petrol/gas patrol, I am having trouble keeping water in the radiator, overheating blows water in the overflow bottle and overflows it. Have a new aluminium 3 core radiator, thermo fan cuts in and out at around 85 deg, cold thermostat opens at around 70 deg. I can sit it idling for hours the fan cuts in and out fine temperature gauge sits below half. Temp is fine around town. Went on a short trip 3hrs fine, when we got into town temp went up to nearly high turned the heater on temp went down. Stoped for a couple of hours added 2 litres of water headed home, on the way home turned off the air con for a bit may be 10k’s turned it back on up goes the temp again high not ¾ a bit more then plummets down to just over half watched this for a bit then turned the heater on again temp came down to “normal” left the heater on for about 30sec turned the A/C back on all was good until we got back into town up it goes again. Got home added another 2-3 litres again. Any thoughts would it have anything to do with the A/C radiator in front (it does get quite hot)