My A/C works very well in the morning, but the compressor will not run in the afternoon. Cooling fans were recently inconsistant & eventually inoperable; Mitsu mech (by phone) suggested a possible relation. Replaced fan assy this weekend, but problem persist. When it cools, it cools real well. The only consistancy I've found so far is the time of day. Pretty hot afternoons here recently. Don't see how that would effect the system. Fault persist even when engine has been off & is 'cooled'.
A/C intermittently fails on 2003 Mitsubishi Outlander
by dmont in Summerville, SC on August 23, 2010
ANSWER by fordlover78 , August 23, 2010
R 134 has a fairly high expansion rate. What is most likely occurring is, your freon level is filled slightly over normal capacity. when it's cool outside, the system runs normally but when the temp. climbs in the afternoon, the freon expands above the acceptable pressure level, tripping the high pressure switch to disable the compressor. Have a professional remove 1/4 lb. at a time during the hottest part of the day till system runs normally. if freon level is OK, you may have a partial blockage in the system causing pressure build up in the same manner. Good luck.