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Pressure good but no cold air
Posted: Wed Jul 05, 2017 5:03 pm
by moundtown
The A/C in my 2000 Toyota Echo is not blowing cold air. I thought that maybe the refrigerant level was low so I bought a recharge kit. With the car idling, the A/C set to maximum cooling, and the compressor engaged, I connected the gauge that came with the kit to the low pressure connection. The gauge read at nearly 45 psi which is at the upper range of the (blue) target zone so I didn't add any refrigerant. Everything appears to be working as it should although the compressor seems to never disengage (unless I turn off the A/C). There is water dripping from the evaporator drain hose. Any suggestions as to what might be going on?
Thanks
Re: Pressure good but no cold air
Posted: Thu Jul 06, 2017 6:33 am
by Cusser
When AC is on for a few minutes, feel the inlet and outlet tubes to the evaporator at the engine firewall.
For starters though, you really need to test both high side and low side pressures at about 1800 rpm. The single low side gauge on "simple" store units really doesn't help you much, can actually cause issues due to wrong information.
And don't blindly add anything, especially stay away from any cans stating sealer or seals leaks EVER; best is to have refrigerant pulled out and weighed by a shop to determine refrigerant level, the only real way.
Re: Pressure good but no cold air
Posted: Thu Jul 06, 2017 7:14 am
by Dougflas
You may not have a refrigeration problem. It could be the blend doors. Try clamping off the heater hoses.
Re: Pressure good but no cold air
Posted: Thu Jul 06, 2017 11:35 am
by moundtown
Cusser wrote:When AC is on for a few minutes, feel the inlet and outlet tubes to the evaporator at the engine firewall.
For starters though, you really need to test both high side and low side pressures at about 1800 rpm. The single low side gauge on "simple" store units really doesn't help you much, can actually cause issues due to wrong information.
And don't blindly add anything, especially stay away from any cans stating sealer or seals leaks EVER; best is to have refrigerant pulled out and weighed by a shop to determine refrigerant level, the only real way.
Thanks for responding. After running the A/C for a few minutes the low side tube is cool (not cold) and the high side is warm. Can I buy the gauges to test the both low and high sides at an auto parts store?
Re: Pressure good but no cold air
Posted: Thu Jul 06, 2017 11:37 am
by moundtown
Dougflas wrote:You may not have a refrigeration problem. It could be the blend doors. Try clamping off the heater hoses.
Thanks for responding. I clamped off the heater hoses and it made no difference.
Re: Pressure good but no cold air
Posted: Fri Jul 07, 2017 7:05 am
by Cusser
Cusser wrote:1. You really need to test both high side and low side pressures at about 1800 rpm.
2. Best is to have refrigerant pulled out and weighed by a shop to determine refrigerant level, the only real way.