A/C cooling, but not efficiently or down to temps as before

[AZUWhuskies]

Hi,

I appreciate in advance any advice or help from this forum. I own a 2014 Infiniti Q50, which I bought new and have driven in AZ since day 1. It has always had very cold a/c, probably blowing about 50F from the vents even in the dead heat of the AZ summer which can get up to 110-115F.

Just a few weeks ago, I measured the low side port pressure of the a/c system. The ambient was about 105F at the time, and the reading was 41 PSI at idle, which is about 600-700 RPM. From the charts I’ve looked at, PSI at this ambient should be closer to 50-55 PSI, so I thought my system was low. This has been a painful lesson of “if it ain’t broke, don’t fix it” as it was blowing very cold already even though reading came back at 41 PSI. I had some R134a A/C pro refrigerant and followed the instructions and added some to the system. PSI went up to about 43-44 PSI. However, I noticed immediately the air from the vents did not blow as cold as it used to. I worried I overcharged the system and took it into the dealer.

Dealer did a evac and recharge and told me that it wasn’t overcharged, but instead was low. Manufacturer specs state car takes 1.1 lbs of R134a but it only had about 0.9 lbs. They charged it up to factory spec and told me I was good to go. This was very odd to me since the system was blowing out very cold air despite being low on refrigerant and this was before I event attempted to add any myself.

Unfortunately, the recharge did not solve the issue and the a/c system does not blow colder than about 60-62F right now. In the past, if I had parked my vehicle out in the sun during the AZ summers, the system would be able to easily cool down the cabin after a few minutes to the point where I had to turn the fan down to the lowest setting otherwise it would be too cold. Now at a vent temp of 60F, it doesn’t get the cabin to cool down at all even after an hour drive as I’ve had to keep the fan blowing on high the entire time.

I took it back to the dealer. They did another evac and recharge and no difference. They are telling me that everything is within Nissan/Infiniti specs and that they don’t have any recommendations on next steps. This has been really frustrating as even the loaner I got from them was blowing air from vents at 50F whereas my Q50 is blowing at 60F+ in the same ambient temp and environment of 115F.

Someone else on another forum suggested I test the low side PSI with car at 1500-2000 RPM. I did so during an ambient of 110F and when at 1500, about 40 PSI, and at 2000 rpm 35 PSI. They suggested that this was low and I needed to add more R134a but my concern is dealer already added the manufacturing requirement of 1.1 lbs and I wouldn’t want to overcharge the system.

The entire system was working just perfectly fine before I tried to add a little R134A myself and now it’s not and I’m baffled. Dealer said all system parts look to be operational and fine so not sure what to do next.

Any help is much appreciated.

[bohica2xo]

Was there any magic sauce in the 134a you added?

This looks like a control valve issue at this point, but we need high side pressures to really evaluate the problem

Full load test. Cabin fan on highest speed doors open. Run the engine above 1500 rpm for at least 90 seconds to stabilize the system. With the engine speed above 1500, record the High and Low pressures and the vent temperature. Post them here

[AZUWhuskies]

Will pick up a manifold gauge so I can measure both high and low side PSI and report back.

FYI this was the R134A I bought… 8. Posting links to outside businesses, including online enterprises, vendors, and auction sites, is prohibited. However, it may consist of pictures or videos that clarify your question.

[JohnHere]

The refrigerant that you installed contains sealer, which clogs-up a system. That's why these products are known as Death Kits in the trade. Unfortunately, one or more components in your A/C system were affected by the sealer, creating...I'm afraid to say...potentially serious and costly problems you didn't have before. Regretfully, you didn't ask the Forum before installing that stuff.

[AZUWhuskies]

I know, as mentioned lessened learned of if it ain’t broke don’t fix it. I only added just a little of that product, enough to increase PSI from ~41 PSI to ~43 PSI. Is that enough to cause this much of an issue? Will be picking up manifold gauge later today to see what the high and low pressure is.

[JohnHere]

Any sealer is too much, especially in a system that holds only 17.6 ounces of refrigerant. That being said, pressures won't tell us how much refrigerant the system contains. The only way to "gauge" a correct charge is to weigh it into a system under vacuum. For that reason, "topping up" is never something I recommend

[bohica2xo]

Would not take much of something like this to make a control valve act up



"Just top it up. I found a chart online."

Never a good idea.

The control valve is externally replaceable on that compressor. Depending on the miles it might make more sense to replace the compressor with a new Sanden unit, because the system must be recovered to replace the valve anyway.

.

[tbirdtbird]

Notice the can says 'seals leaks'
This stuff is very gooey and clogs up delicate parts. They should be taken off the market.
There is also the issue of the hose attached to the can having air in it, so you are injecting not only sealer but also air, which is the dire enemy of a system