I am hoping someone here can offer some insight to finally find a solution to my ongoing AC problem. I have a 2004 Sentra (~80K miles and runs great) that has been without adequate AC for about 2 years. The issue is that the vent temperature never gets very cold. I have run a number of tests with a high quality/accurate probe inserted in one of the center vents, with the AC turned all the way to cold and the fan on full blast, logging every minute for a minimum of 30 minutes under city and highway driving. For city driving, 3 tests, the vent temperature has gone down to 80F (ambient 94F), 77F (ambient 90F) and 70F (ambient 86F). One test on the highway produced 65F (ambient 90F). An observation I have made, and shown in testing, is if the car sits still (parked, stop light, etc.) the temperature climbs. If I am moving, and the faster I go, the temperature drops.
Below is a list of what work has been done on the AC system by my mechanic. I want to give credit to my mechanic as all of their other work has been impeccable and their honesty in cost and need of work (even doing some free fixes just to get me going for a bit longer before needing to bring the car in for further work). Also, my mechanic is determined to fix this issue and has put in at least 15 hours, over multiple sessions, of free labor trying to tackle this (my car's AC issue has become a bit of a white whale for him).
- Replace AC Suction Hose, Recharge
- AC Evaporator
- Expansion Valve & Drier
- AC Compressor (done with no labor charge)
- AC Condenser and Drier Assembly (at a discount)
Some additional information that may help:
- One thing to note is that the replacement evaporator was aftermarket (OEM not available) so brackets were fabricated and install due to a slight difference in size.
- Pressures are always spot on when I take the car back home and when I return it and the AC lines (cold/hot) in the engine compartment show expected temperatures when measured with an IR temperature gun.
- On a related note, if I start the car with the AC off and then turn the blower knob to full blast I sometimes hear a "clunk" sound. Of course I have never been able to reproduce this with my mechanic present.
If anyone has any insights or questions please let me know. I am in Florida and it is starting to get brutal with the humidity.