A/C Problem

[roadrunner68]

Hi, i have an ongoing problem with my A/C on my 3.2 Boxster S (MY01) Whats happening is when it's charged/gassed & you turn it on it blows the gas out of the release valve on the compressor. Currently i've replaced both condedsers, dryer,pressure valve & the compressor.

Does anybody have any ideas?

Thanks.

[pk2]

Might call a couple of AC shops and act semi dumb? see if you can get an answer that makes sence?

Regards, pk

[roadrunner68]

I did call an A/C specialist today who seems to think one of the condensers may be blocked, but their new.

[JFP in PA]

What high and low line pressures are you seeing when this happens?

[roadrunner68]

What high and low line pressures are you seeing when this happens?

The low pressure seems fine, 2-5 bar, the high pressure blows out at 5 bar.

[JFP in PA]

What high and low line pressures are you seeing when this happens?

The low pressure seems fine, 2-5 bar, the high pressure blows out at 5 bar.

The line pressures vary with ambient temps, but using 68F (20C) as a reference point, you should have 1.4 to 1.7 Bar on the low side; 9 to 15 Bar on the high side. Without the correct pressure differential, the system cannot operate correctly or cool properly. The vent valve on the compressor is designed to open if the system over pressures, so it may be the source of your issues. Unless the system is being overfilled, I'd have to say the compressor is the problem as I do not think the valve is available by itself.

A couple of additional thoughts: Are you sure that additional oil was not added to the replacement compressor? Reason I ask is that replacement units come pre-filled with oil from the factory; adding more oil will overfill the unit (common mistake). You are supposed to pull the oil plug and remove approximately 80 cc of oil from the unit to compensate for oil already in the remaining components (lines, expansion valve, fluid tank, etc.), assuming you are not changing them as well. Doing this will leave approximately 120 cc of oil in the compressor. Too much oil will cause the compressor vent to blow off to prevent the system from creating a hydraulic lock. If you are unsure of how much oil is in the system, it might be a good idea to empty the unit, measuring how much you get out, and then start over. The system is rated for 195 cc, +/- 15 cc for the entire system (you have to adjust for the oil that remains in the other components).

If you are sure the correct amount of oil is in the system, I would pull all the refrigerant out, and carefully recharge the unit to the correct pressure differential for the ambient temp; if the system still vents, you need a compressor.

[JFP in PA]

An additional thought: When you replaced all the components, was the system fully evacuated and held under vacuum for a period of time? Reason I ask is that ambient moisture left in the system can freeze under certain conditions and cause the unit to over pressure................

[roadrunner68]

I think i've found the problem, one of the new condensers is blocked.

[JFP in PA]

I think i've found the problem, one of the new condensers is blocked.

How was it blocked?