Automotive Air Conditioning Information Forum

I’m having trouble with my car’s Air conditioning it seems to be a constant problem since owning the car for 6 years. For the first year no problem at all until it started blowing hot when running so brought a bottle of refrigerate and topped it up to the right pressure on the gauge and it worked fine until last year. I heard it click off while drive and it started blowing hot air again. So took it to a garage and they said it was the compressor so got them to replace the part and it worked for about 2 months then failed again. I read up on some information online and got my self some proper gauges and tried to identify the problem myself so I plugged them in and left them over night. The low side stayed at about 30 psi so I’m assuming there’s no leak but the high side is only stays at 40 psi even when running. The compressor clicks on and off fine so surely it can’t be the compressor again. The garage isn’t there anymore so I can’t take it back so any help would be appreciated

Let us know the vehicle's year, make, model, engine size, and mileage and we'll try to help you diagnose this. Are you in the USA or another country?

Pezza213k wrote: ↑Sat May 21, 2022 4:34 am bought a bottle of refrigerate and topped it up to the right pressure

Please let us know if this bottle of refrigerant contained any sealer, also

Vauxhall Astra sports tourer 2013 2.0 cdti with 55000 mileage, the refrigerate I used was an off the shelf bottle r134a called ac pro, it’s says it can seal ac leaks. I live in the uk

40 psi hi side is waay too low, are you sure the couplers are depressing the schrader cores properly? Some of the cheap couplers fail at this because they are not machined to the SAE standard.
Also, an important FYI (too late now) never add sealer to an AC system. It is bad stuff and will clog everything up, no matter what the label says.
Yikes, you even have that ACPro crap in England that has become a rampant disease on this side of the pond. It has ruined a lot of AC systems.

So I’ve just checked the attachments to make sure they are connecting properly and now the gauges are reading low side 20 psi which now the compressor won’t engage which I would expect to happen without the correct pressures but the high side fluctuated abit and dropped down and sitting 10 psi now. So there must be a leak somewhere. Should the high side lose pressure if it the low side leaking? Or could it be a faulty expansion valve near the evaporator, something I’ve just found online

Pezza213k wrote: ↑Sat May 21, 2022 8:57 am Vauxhall Astra sports tourer 2013 2.0 cdti with 55000 mileage, the refrigerate I used was an off the shelf bottle r134a called ac pro, it’s says it can seal ac leaks. I live in the uk

Thanks for that info.

We neither have that make and model of vehicle here in the USA, nor do I have the specs for it, but I presume it is an R-134a system. Check for an under-hood decal that gives the A/C system info.

As said previously, the static pressures you posted are very low, indicating that the system is virtually empty of refrigerant. It's definitely leaking out someplace, and the leak or leaks could be virtually anywhere.

With those pressures, albeit low, you should still have enough refrigerant in the system for leak checking. If not, you could puff-in a little more refrigerant (without any sealer). It doesn't have to be a full charge, just enough to bring the pressures up a bit.

If you don't have an electronic refrigerant detector ("sniffer") or UV dye in the system, look for signs of oil, which would suggest refrigerant loss at that point because the refrigerant usually carries some oil with it. Also leak-check everything possible using a water-and-dish-soap solution, spraying that on all the visible components and connection points under the hood (bonnet ).

The first things to check are all around the condenser, compressor, receiver/dryer or accumulator, lines/hoses, and whatever portion of the evaporator that might be visible.

Pezza213k wrote: ↑Sat May 21, 2022 10:07 am Should the high side lose pressure if it the low side leaking?

Yes, indeed.

Oops I didn't realize the 30/40 originally posted was with the comp off, I thought it was running, meaning that under those circumstances the low side was OK
John nailed it, low charge=leak

Yes from my original post when the pressures was 30 psi low side but only 40 psi on the high side the compressor was engage and running. It’s only when I went out 30mins ago to check the gauge attachments was connecting properly I’ve now got a reading of 20 psi low side which now is not enough pressure for the compressor to turn on and start running and 10 psi on the high side now. So I’ve just tried to put more refrigerate in and took the low side abit higher to 40 psi which the compressor started running again but the high side wouldn’t go pass 25 psi and still warm air coming through the vents . I’ll test the pressures again tomorrow too see if they drop.