Land Rover Repair: 95 Disco overheating, tensioner pulley, fan clutch

Question
I own a 95 disco. I have replaced the water-pump, radiator, fan clutch and thermostat. The oil is clean, so is the coolant. After running 25 minutes on the highway the ac cuts out and the gauge spikes to the redline when I come to a stop. Have I missed something, what do you suggest?

Answer
Hi Keith,

could you have a problem with your serpentine belt?  
Is it possible that the belt is worn or slipping when the AC is engaged?  
How is the condition of your tensioner pulley?
How is your AC compressor?

All of these components could cause this problem.

Best of luck,

JohnMc