QuestionI own a 01 LR SE7, I just replaced the water pump and thermostat. The vehicle continues to overheat after be on for about 45-1hr when the AC is on. As soon as turn off the AC, the gauge will drop back down. Can anyone help?
AnswerHi James,
If the temp reading is getting too high it could be a sign that you have a problem within the AC system - maybe the compressor clutch is failing or there is a bearing problem somewhere. It could also be a headgasket problem - common for series II Disco's. Maybe the serpentine belt is slipping or the tensioner pulley is starting to fail. Then there is the external temp sensor and the electrical cooling fan - both work together:
"Engine cooling fan control
While the A/C system is on, operation of the electric engine cooling fan, to assist refrigerant
condenser operation, is determined by a combination of vehicle speed and external air
temperature. When cooling fan operation is required, the ATC ECU outputs a cooling fan request
to the ECM, which then energises the cooling fan relay. The cooling fan request is output if
vehicle speed is 80 km/h or less while the external air temperature is 28 °C (82 °F) or more.
The request is cancelled, and the cooling fan switched off, if either the vehicle speed
increases to 100 km/h, or the external air temperature decreases to 25 °C (77 °F)."
Check the serpentine belt, if it looks worn or cracked, replace it. If it's been on your Disco for too long, replace it. Consider having the cooling system pressure tested. Inspect your radiator and condensor
Best of luck,
JohnMc
