Rep Power: 0

Hi,

The A/C on my 2001 Civic is warm. Same temp as the air outside. I've done a bit of research, but not making much progress. I checked the compressor and it is engaging when I hit the A/C button(sometimes it takes a few seconds).

Could you guide me what to do next or things I can test?

Thank you!

 
Rep Power: 134

The A/C clutch engages the compressor when A/C button is pressed? Sometimes the gap between the clutch and compressor becomes to much that the magnetic clutch cannot engage anymore - solution remove shim(s) on shaft to reduce gap.
Check A/C system for leaks and proper amount of refrigerant.

 
Rep Power: 0

Yes, it does engage, but sometimes it takes a several seconds. Is that normal?

 
Rep Power: 222

Should engage instantly, clutch gap is probably too big

 
Rep Power: 0

Ok, so I got a A/C gauge set and this is what it reads. The outside air temp was 73 and the humidity was 81%. The air coming out of the vents was 86 degrees.

With the car off, the High and Low sides were both about 57 PSI. With the compressor engaged the High was 75 PSI and the Low was 2 PSI.

What does this mean?

 
Rep Power: 224

Sounds like it's low on refrigerant. With that ambient air temperature you should see ~35-40 psi on the low side and ~150-170 on the high side. The A/C pressure switch should shutoff the compressor if the pressure is less than 28 psi, not sure how you managed to read 2 psi.

If the car has sat for a while both high and low should be about the same, I believe around 80-90 psi.

 
Rep Power: 0

Thank you for the information. I will test it again today and see if I get the same readings. I will let you know.

I should have all the refrigerant removed at a shop, then vacuum the system myself, and then fill it up, right?

 
Rep Power: 224

As long as the system isn't empty you can just add refrigerant. The only way to get it filled with the exact amount spec'd by Honda is to get it removed first. But you should be ok just adding until the desired pressures are achieved. You must be careful not to overcharge the system though.

 
Rep Power: 0

Tested again, The outside air temp was 65 and the humidity was 38%.

With the car off, the High and Low sides were both about 35 PSI. With the car running for 5 minutes and the compressor engaged the High was 62 PSI and the Low was -5 PSI.

Why is it pulling a vacuum?

 
Rep Power: 224

The compressor should not even be engaging with the pressure that low. Is the compressor engaged all the time even with the A/C off?

Do your gauges read 0 psi when not connected to the car and nothing trapped in the hoses? If so it is definitely low on refrigerant but you still have the issue of the compressor running when it shouldn't.

 
Rep Power: 0

No, the clutch turns off when I turn the a/c off. I can instantly engage the clutch and turn it off with the button.

The gauges do read 0 or 1 when not connected.

 
Rep Power: 224

I have googled low side going to vacuum, it indicates the system has a blockage somewhere. Maybe a bad expansion valve.

 
Rep Power: 0

Thank you for the information. I am going to wait until the spring to do anything on it because I don't need it now.

 
Rep Power: 134

Actually you should be using the A/C on hot temperature in the winter to defrost the windshield - hot dry air clears humidity faster. Using the A/C year-round also lubricates the compressor and rubber hoses via PAG oil in the refrigerant to prolong the life of your system and potentially reduce costly repairs.