My 2009 Honda Fit purchased two years ago with 35k miles on the clock is experiencing A/C issues.
When I purchased the car, the a/c worked but was mediocre. So I went the local a/c guy and he ostensibly recovered existing refrigerant, evacuated system with vacuum pump and recharged system with r134a and dye. A/C worked much better first summer season with vent temps 35-40 degrees below ambient (measured with Fluke meter). At beginning of second summer season, A/C still seemed to be working OK but maybe not as good as prior summer. A/C subsequently began to fail. I noticed this first after driving car at high revs -- shifting near redline and driving hard. Not sure if this is related to issues or not. A/C then started working again but not so well. After a few days, a/c would turn on (with compressor and condenser & radiator fans) but would cut out prematurely. Finally a/c would turn on with initial start up of car but would turn off within minutes.
Thinking that I had a leak, I pulled front fascia off car to better shine my UV light (already had this in my arsenal of tools) and discovered leaks at lower condenser connections (one at receiver / dryer) and one at output line connection. See photos of florescent dye tracks. No other leaks were detected -- none on lines, none at compressor, none at ports, none anywhere else on condenser including fins and none at drip tube of evaporator or water droplets from evaporator). So I bought a can of pure r134a (no additives) and a set of yellow jacket manifold gauges/hoses.
My initial pressures at idle before adding any refrigerant were 25 / 105 psi on a 87 degree day. Raising rpm up to 2,000 resulted in an increase to 34/135. So it seemed to me that suction side might be a little low and discharge sided was very low. At shutdown, the low side and high side pressures remained more or less static -- they did not rapidly equalize. Honda service manual calls for high pressure of around 250psi at then existing air inflow temp and humidity levels.
Hoping my problem was related to low charge and willing to charge system up as a diagnostic test (i.e., without repairing leaks / replacing receiver/drier first), I then added 3 ozs of refrigerant. I used super accurate electronic lab scale that I happen to own to measure weight of the can as I added refrigerant. I added only 3 ozs because I was concerned about overcharging system. Some improvement in pressures resulted with low side of 35 psi and high side of 140 psi at idle. Raising rpms did not seem to change pressures by much. There was also some improvement in a/c function with less cycling but a/c would eventually quit after 5 minutes or so of driving car.
I've searched high and low for diagnosis based upon normal low side pressure with low high side pressure but can not find very much to point me in the right direction. Also, I wonder if those condenser connection leaks with the dye tracks represent a major or minor leak? I guess I could measure the at rest pressures of a/c system over the next week or so but changes in ambient temperatures will make that somewhat difficult.
BTW, there are no abnormal noises of any sort coming from compressor or rest of the system.
Any suggestions? Possible causes? I suppose that I could fix the leaks and replace receiver / drier and recharge system with precise amount of refrigerant called for (15 ozs for this small system) and see what happens but it seems to me that there is probably enough refrigerant in system now given adequate suction pressures and that the very low discharge pressure is meaningful.
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