disco 300tdi overheating

i think you do jest ,defenders suffer as well as discos ,not as commonly as defenders are nowhere near as common as discos ,header tank is similar height on both ,header tank needs filling on both to overflowing to get coolant out of thermostat housing plug ,90% of overheating in my experience is down to rad filling and emptying on the same side unlike 200tdi and rad not cooling over entire surface ,the other 10% is down to either never checking level of faulty thermostat etc or just 15 years or so of heating cooling cycles is enough for head gasket to go ,cooling system on 300 is more than adequate if in good order,modifying it would be pointless

The Disco 300 I once owned had a blocked heater matrix which screwed up the cooling system and gave overheating issues. When I bypassed the heater by connecting the input to output lines (at the back of engine) the overheating wasn't too much of a problem as long I as didn't put my foot down. Once the matrix was replaced the overheating issue disappeared.

land rover discovery 300tdi overheating gon throw 5 water pumps