Automotive Air Conditioning Information Forum

Guys, please help me with your expert opinions. My car is honda civic 2008. AC is not cooling. Static pressure is 100psi at 100 F temperature. While AC is on with engine idle i have around 30 psi low side and 150 psi high side and never cycles. When i turn off the AC, pressures equalize instantly back to 100 psi i mean i turned off the ac and look at gauges it was 100 psi. Fan is working fine. I doubt its a bad expansion valve. What do you guys think ? Recently i went to a mechanic and cleaned all the lines and put a new condenser (with dryer). Cleaned valve and evaporator as well. It worked for a couple of days and suddenly started to blow warm air again.

You have a leak. It is undercharged, just a few days after service.

bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.

Take it back to the shop, it's covered by their warranty.

bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.

They did a pressure test to find leaks and found nothing. Besides, static pressure and working pressures are very good as i mentioned. I believe its supposed to blow cold air at those pressures. Please correct me if im wrong. What do you think about the fact that the pressures equalize instantly ?

CrazyMel wrote:

bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.

I believe its supposed to blow cold air at those pressures.

CrazyMel wrote:While AC is on with engine idle i have around 30 psi low side and 150 psi high side

Should really measure such pressures at bout 2000 rpm. At 2000 rpm at 100F, I would expect more like 35 psi and 250 psi. We assume the cooling was OK when you picked the car up at the shop, then a few days later was not cooing well. That indicates a leak.

Cusser wrote:

CrazyMel wrote:

bohica2xo wrote:You have a leak. It is undercharged, just a few days after service.

I believe its supposed to blow cold air at those pressures.

CrazyMel wrote:While AC is on with engine idle i have around 30 psi low side and 150 psi high side

Should really measure such pressures at bout 2000 rpm. At 2000 rpm at 100F, I would expect more like 35 psi and 250 psi. We assume the cooling was OK when you picked the car up at the shop, then a few days later was not cooing well. That indicates a leak.

Cooling was really good for 2-3 days and it was not a gradual decrease which would have happened if it was a leak. Cooling dispappeared suddenly. This happened more than a week back. Still there is a static pressure of 100 psi so i belive if there was a leak this should be much less by now. I was alone so couldnt check pressures @ 2000 rpm. Anyway, there's a new expansion valve on the way i will insrall it and let you know the results

It would have a static pressure of 100 psi with a single ounce of refrigerant in it. That is the nature of refrigerant gasses.

You have a leak. It crossed below the critical charge weight & quit cooling.

But keep throwing cheap online auction parts at it and you may accidentally fix the leak along the way...

Probably you are right. But then why couldnt we catch the leak with pressure test ? Tried with UV dye as well.
Can expansion valve leak from somewhere other than the connections?

Remember that service valve caps must be intact to seal a system - check those !!!

Cusser wrote:Remember that service valve caps must be intact to seal a system - check those !!!

Checked this already. No issues with the valves or caps.
I have some doubt about compressor itself as well. Because pressures equalize as soon as i turn off the system. Did some research in the internet and it was mentioned somewhere as a symptom of bad discharge valve inside compressor.