my 96 4.0 hse rangerover overheats when working hard or travelling at over 90 mph for a while,if you slow down below this speed or ease off the throttle the temp soon returns to normal,i have changed the rad,waterpump,viscous fan &t/stat,it does not pressurize the water system, last weekend i replace the head gaskets & skimmed the heads as it was the only thing left that i could think of but still the same. The only thing i now can try is fitting genuine parts rather than non gen. but dont have much hope that this is the problem,if anyone has had similar problems please let me know.

 

Is it actually boiling off coolant, or just temp gage reading high ?

 

i am sure it is getting hot because if i dont slow down it continues to get hotter until in the red,the gauge normally stays right in the centre no matter what type of load it is under.

 

If you are not loosing coolant, there is a TIB on this issue. It has to do with the temp sender ground.