2019 Nissan Frontier AC troubleshooting (Video link attached)

[mcFish]

Mist the condenser and post pressures & temp.

I did. Pressure dropped little bit but not air temp
https://youtube.com/shorts/uoRBMdIbZhc?feature=share

[Tim]

Seems to be cycling pretty quickly. 1.5 Lbs is the correct refrigerant; what's the sticker on the radiator support say.

[mcFish]

Yes, correct

IMG_2915 Medium.jpeg (86.09 KiB) Viewed 242 times

[Tim]

I've got to get back to some corporate stuff. Check that the heater core is not allowing hot water into the core when in a/c mode. As in the other post. Have you overloaded the oil capacity?

[mcFish]

I didn't evacuate/refill oil. And I assume yellow dye is OEM Nissan Luminous oil.
Hot coolant is always flowing through heater core here and only air flow regulates by diverters.
I've checked heat - works well, heats up and shuts down right after I've put temperature knob to Low.
The suction line is pretty freezing, just not enough time to pump it through evaporator.

I found this similar topic: viewtopic.php?t=14488
Nissan Pathfinder - with two evaporators - issue was: block expansion valve for the front evaporator.

[JohnHere]

You'll never achieve reasonably cool vent temperatures with a low-side reading of ~50 PSI. If you indeed have a full charge of refrigerant in this fixed-displacement system, weighed-in precisely as it should be, then you probably have a condensing problem, as Tim inferred, or a TXV issue.

Try misting the condenser using a garden hose and nozzle and see what the pressures do. Spray it down real good. The spray bottle might not be good enough.

This vehicle has front A/C only, correct?

[mcFish]

Since I've recharged 670g of freon - I've added 40g more to reach 700g plus/minus 50g as on label. (I've used scale every time)
Took for another ride: same temperature.
In the garage with warmer outside: gages are 50-60/300, condenser fan is constantly running, can not see compressor because it's deep but assume that compressor is engaged and running - suction line is getting warm. Air vent temp: 72F
Front AC only.
Will try garden hose. What are we trying to achieve? What readings should I see?

https://youtube.com/shorts/amM3QpheI7Q?feature=share

[JohnHere]

Will try garden hose. What are we trying to achieve? What readings should I see?

By spraying the condenser with water, you are trying to verify the effectiveness of the condenser, whether it has external debris clinging to it, whether it's internally clogged, whether it's sealed around the edges so that air can't bypass the core, and whether the pressures come down. If not the latter, then you'll know that the condenser isn't doing its job for some reason.

Key to this also depends on the ambient temperature, measured just in front of the condenser/radiator stack. For an 85°F ambient, you should see ~180-210 PSI on the high-pressure side. For a 90°F ambient, you should see ~190-225 PSI. For a 95°F ambient, you should see ~200-240 PSI. And so on. In each instance, the low side should hover ~30 PSI.

[Tim]

Low Side High / High Side High: Overcharged system or poor airflow across the condenser.

Even AI is saying it's a charge or airflow issue. I'm surprised running a garden hose over the condenser did not bring the readings down. If you have an infrared temp gauge. With the a/c is running, check different areas of the condenser. With PF condensers, you may have blocked passages and still have refrigerant flow.

[mcFish]

Ok, my last test for today!
Ambient temp 99F. Static 100 psi.
Garden hose: High side is dropped to 150F, low side jumps 40-70 as compressor On/Off.
Low side pipe temperature is not changing, barely cold, same as air vent temp!

IMG_2939 Medium.jpeg (90.59 KiB) Viewed 164 times

Garden hose at the beginning: https://youtube.com/shorts/hu_M75rv3_g?feature=share
At the end: https://youtube.com/shorts/_tnh5z9CVkE?feature=share