The AC on my 1999 Honda Civic 1.6 SOHC was not working well. I recharged the system it mostly works. It doesn't work well when I am at idle at a stop light or parked. I have the impression that the engine compartment needs to be cool enough for the AC to work properly. I thought the radiator fan wasn't coming on frequently enough so I ran a temporary toggle switch to keep the radiator fan on and it allows the AC to keep blowing cold air while stopped. However, in trouble shooting the radiator fan, I believe it is working correctly. I used a IR thermometer to check the temperature of the thermostat housing and the radiator fan kicks on when it reads 193 degrees (book says it should come on at 196). It only stays on for a minute but as soon as it goes off, the thermostat housing temperature is 180 degrees. Seems ok to me. I put a gauge set on and here is what I found:
Engine off- Low side spikes high and High side reads 100
Engine cold with AC off- Low side spikes high and High side reads 100 (no change from engine being off)
Turn AC on before engine gets up to temperature and the guages read 20 on the Low side and 140 on the high side
Once the engine gets up to temperature the Low side reads about 50 and the High side stays at 140.
As soon as I shut off the AC, the Low side goes up to 60 and slowly but steadily rises and the High side drops to 100 but eventually comes back to 140.
The book I have says that normal operating pressures are Low Side 23-36 and High side 240 to 300.
I have to admit that I'm a bit confused by the book I have as there may be more than one cause to my problem ranging from a "slightly low charge" to an Expansion Valve problem. Per the book, with a high reading on the Low Side and a low reading on the High Side, I should have a "noisy compressor" but the compressor is working fine. Any insight? PS- I haven't dug into the evaporator area but I don't see any leaks (I used a dye when I recharged last month). I have considered an after market fan control switch which will turn on the radiator fan whenever the AC is turned on but I'm not sure what the consequences are of running the coolant to cold. (If that is even a concern). I hope I have given enough information for you to help.
have the same problem?
Friday, August 12th, 2011 AT 1:52 AM