2017 Nissan Quest A/C issue

[mjk1967]

Hello.
It's been a long time since I've had an AC issue, so I'll try to fill you in.

Today -- ungodly hot - real feel 97. I'm sure the Southerners will laugh. Work out of my van, so I'm in it a good portion of the day. Yesterday, similar temps, my AC was working completely normally -- I usually have it at 70.

Today, its barely blowing cool air at 63. Compressor is kicking on, I do not have HVAC gauges. Typically a leak (from past old cars) doesn't seem to show up this rapidly. Obviously, something is going on -- just have not seen this happen this rapidly.

Any thoughts? Is the system bogging down due to our conditions, or more likely, I am losing refrigerant.

Thanks...

 

[michaelluscher]

Cabin filter clean?
Condenser unobstructed/fans working on all speeds?
Ambient air temp reading on dash within realm of reality?

Compressor short cycling?
Rear A/C functional?

If simple checks get you no where, time to either get a gauge set or have someone with an appropriate machine evacuate and weigh in the appropriate charge
Or, you could try topping off using A/C gauge readings as a guide
IME, doing that on Nissan variable displacement compressors is difficult

Some workflows if you're interested
https://lemon-manuals.la/Nissan-Dat... Air Conditioning System/Diagnosis Procedure/
https://lemon-manuals.la/Nissan-Dat.../Refrigeration System Symptoms/Symptom Table/

 

[mjk1967]

Cabin filter clean?
Condenser unobstructed/fans working on all speeds?
Ambient air temp reading on dash within realm of reality?

Compressor short cycling?
Rear A/C functional?

If simple checks get you no where, time to either get a gauge set or have someone with an appropriate machine evacuate and weigh in the appropriate charge
Or, you could try topping off using A/C gauge readings as a guide
IME, doing that on Nissan variable displacement compressors is difficult

Some workflows if you're interested
https://lemon-manuals.la/Nissan-Datsun/2017/Quest SL/Repair and Diagnosis/Heating, Ventilation & A/C (HVAC)/HVAC Control Systems/Heater & Air Conditioning Control System (Automatic Air Conditioning)/Symptom Diagnosis/Insufficient Cooling/Front Automatic Air Conditioning System/Diagnosis Procedure/
https://lemon-manuals.la/Nissan-Datsun/2017/Quest SL/Repair and Diagnosis/Heating, Ventilation & A/C (HVAC)/HVAC Control Systems/Heater & Air Conditioning System/Symptom Diagnosis/Refrigeration System Symptoms/Symptom Table/

Cabin filter clean, rear a/c working up until Sunday. Don't have evidence of any short-cycling..
I took the easy way off, and dumped some refrigerant in. It's working, if it gets me through the summer, I was planning on trading in next spring/summer. Else, it will go to my mechanic.

 

[JavierH19]

Did you hear any hissing coming out of the Schrader valves when you took the caps off.

 

[mjk1967]

Did you hear any hissing coming out of the Schrader valves when you took the caps off.

I did not...

 

[Chris142]

Suction line cold? If not we need pressure readings.

 

[JavierH19]

I did not...

That's the usual leak location for most vehicles and it's an easy fix. If not then the leak is somewhere else.

Do you have any icing or frosting on the suction line while still running after it has been driven for a while? If you do then you're still low on refrigerant. If it's correctly charged it'll be near freezing and be very cold to the touch and be wet and you'll have a good quick drip In hot humid days. If it's barely cold then it's very undercharged likely under half charged from what the sticker says. Mildly undercharged systems will ice/frost and those tend to only be about 10-30% undercharged from sticker capacity.

I don't suggest leak sealers because they use polymers that react with oxygen and harden which are not good once the system is opened up to air to have something replaced.

But it seems blaster recently came out with a non-polymer non-hardening and oxygen-reacting safe seal both seperate and mixed in r134 that goes as far as to claim that it mixes perfectly with the oil and does not shut down recovery machines or damage other components or clog passages.

So maybe give that a try if you want since you might not keep it for long. They're reputable I don't see them lying about it. My tractor supply has it in stock last I perused but didn't buy. I buy the supertech pure refrigerant since it's the cheapest, I'd never use their stop leak it's most likely the oxygen reacting kind.