Automotive Air Conditioning Information Forum

So I have a 2004 Acura RSX, and the A/C just doesn't blow cold enough.
From what I've measured and what I know so far, I'm thinking it's either a slightly stuck open expansion valve, or air in the system + low charge.

Here's what I got:

Conditions:
Static pressure: 100 psi low, 100 psi hi
Ambient air temp: 92F
Humidity: 24%

Test 1 - Idle, a/c on, recirculate off, windows down, max fan:
Vent Temp: 67F
Pressure:
Low: 39 psi
Hi: 130 psi

Test 2 - 2000 rpm, a/c on, recirculate off, windows down, max fan:
Vent Temp after 2 minutes: 61F
Pressure after 2 minutes:
Low: 16 psi
Hi: 155 psi

The whole time the a/c was on, the compressor and the fan were running constantly, and the pressures above held steady.

Any suggestions?

What makes you think air? Someone been working on the system?
Your charge is low.
Have a shop recover what is in there and recharge to spec on label under hood.
Topping off is not an option with modern systems, the charge has to be just right
BTW you gave data but no ambient

tbirdtbird wrote: ↑Mon Sep 13, 2021 9:32 pm What makes you think air? Someone been working on the system?
Your charge is low.
Have a shop recover what is in there and recharge to spec on label under hood.
Topping off is not an option with modern systems, the charge has to be just right
BTW you gave data but no ambient

I thought air because of the low side pressure being 39 psi at idle (which I thought was kinda high). I figured with a low charge both the low and the high side would be low.

I had the system recharged about a year ago at a shop, so I'm suspecting a leak then.

Sorry, my bad what other ambient info should I include? I got the ambient air temp of the garage I was working in and the humidity in the original post

Can a low charge cause the low side pressure to read high?

tbirdtbird wrote: ↑Mon Sep 13, 2021 9:32 pm Your charge is low.

Have a shop recover what is in there and recharge to spec on label under hood.

This. I'm not a pro, but do have some experience and knowledge. If your 2004 hasn't had any AC work done in like a decade, could just be slight seepage by the compressor seal over the years, and might just need the refrigerant pulled out, weighed, and correct amount added. But you also could have a more-severe leak, so likely the shop will add some AC dye so that if there is such leak/performance drops within a couple of months, the leak could be located.

NEVER ADD ANY SEALER OR REFRIGERANT CONTAINING SEALER.

Sorry, did not see the ambient way at the top of original post

All good, no worries

Thanks for all the info everyone, I really appreciate it

When I get some time I'll add in some UV dye and see if I can find a leak and I'll post some updates on what I find

bachi wrote: ↑Mon Sep 13, 2021 10:11 pm I thought air because of the low side pressure being 39 psi at idle (which I thought was kinda high). I figured with a low charge both the low and the high side would be low.

I agree with previous comments: The system is definitely symptomatic of a low charge.

If it's the compressor shaft seal that's leaking, UV dye might not show up sufficiently unless it's a big leak as said. For small leaks in that area, you're going to need an electronic "sniffer" and either a shower cap or plastic wrap to confine the leaking refrigerant so you can detect it. That technique has been discussed in this Forum at length.

So an update on this

I've put UV dye through the system, ran the a/c for 3 days.

I've checked all the lines with a UV light, starting from the low side pressure line coming out of the firewall, through the entire system all the way back to the high side pressure line going into the firewall. I couldn't find anything

I took the belt off, put a shower cap over the front of the compressor, left it for an hour, and probed the inside with an electric sniffer, nothing either

I know the sniffer works because it does detect the faint traces of refrigerant from the service ports if I hold it really close

I also put the sniffer against the drain hose for the evap, nothing there either

I'm out of ideas, I could rip out the dash to get to the evap, but I don't think it's there judging by the fact that I get nothing from the drain

Any suggestions?

Curious, are you using the plastic caps on the access ports?

Even the best hoses will seep out a small amount of refrigerant over the years.

Would still advise that you have the charge pulled (the recovery machine will tell you how much it got and you can compare that to the under hood sticker), vacuum, and recharge, and go from there.

Yep, I still got the plastic caps for the service ports, and I keep them on

I just took them off for a few mins and put the sniffer really close to check that the sniffer was working (A very, very small amount of refrigerant near the schrader valves, but from what I've read that is normal)

Alright sounds good, I'll get the system pulled when I have some time