I have a 2000 Montero Sport. It has been a great vehicle, but I have had issues with the A/C. Initially I was told by a repair shop that the compressor failed and it was going to cost a large amount of money to fix it...I changed the belts as maintenance and magically the A/C started working again! However, when the sun is out and it is a hot day(roughly 85 deg. F or over) the A/C will blow cold air for a while then it slowly warms up to about outside temperature air and gradually gets cold again for a short time. It does this the whole ride home from work..cycles cold to hot, cold to hot! Miserable 35 mins! On overcast days and slightly cooler days, NO cycling, it just stays very cold and comfortable in the cabin. The low side pressure is in the full range and no known leaks! Any thoughts?????? I am tired of hot air in the face on hot days!
Thank you for any help on things to try!

 

you need to replace the expansion valve

 

Thank you, I will look up what that involves to see if it is something I can handle myself.