A/C refrigerant over charged or under charged?
#1
A/C refrigerant over charged or under charged?
My 96 Maxima A/C is not blowing cool air, here is what happened. About 2 weeks ago, I felt A/C thought was cold, but not as cold as I like, so I bought a can of 134a and charged it, it improved little. Last weekend, wife took the car out and called me saying fan 1,2 and 3 were not working, only 4 is working but not very cool, so I did some research here and found that i might be the bad blower resistor, so I replaced it, that solved the fan problem, however, the A/C seemed getting worse, little cool air coming out at fan speed 4, so I thought, could it be a leak or something causing the drop of the refrigerant? I went to bought another 2 12oz cans of 134a and started charging it again, about half can in, I noticed that the compressor clutch is not engaging all the time, it kicked in and off every few seconds. I read Nissan's maintenance menu, it states that the clutch will not engage if there is not enough refrigerant in the system, so I followed some advice here and jump the compressor, the clutch engaged and I started charging again, then I heard a big hiss sound and smoke, also notice some green fluid leaking out and also some foul smells, I thought I blown out some pipe, but it looked the leaking stopped as soon as I stop the charging. The A/C now is totally not blowing cool air, the low side pressure is around 75psi and clutch won't engage. So yesterday, I tried to put another can of refrigerant in, same thing happened, hiss and leaking green fluid (radiator coolant I guess), I was able to bring the low pressure down around 45psi but it slowing went back to around 70psi while I am still charging. I stopped charging, did more reading, the menu also said if the pressure is higher than certain psi, the pressure relief valve opens to release some pressure, so I guess the hiss sound and green fluid is due to the pressure relief valve opened. further reading found out that if both low and high pressure are high, it might be the system has been over charged. Now my A/C only blows very week cool air when just started, after little driving, clutch kicked off, no cool air at all.
So my question is, does this sound that I over charged the system? How do I reduce the refrigerant? From low pressure side or high pressure side?
So my question is, does this sound that I over charged the system? How do I reduce the refrigerant? From low pressure side or high pressure side?
#2
Member who somehow became The President of The SE-L Club
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R134 is tricky, you really can't get a correct charge with a can. Definately sounds like you blew something with the amount you've attempted to put in.
Have the system evacuated, checked for any leaks and filled correctly, by weight from a vacuum state with a proper A/C service machine. That's the only way to correctly charge an R134 system. Check your local repair shops and make sure they have the machine to perform the work.
Have the system evacuated, checked for any leaks and filled correctly, by weight from a vacuum state with a proper A/C service machine. That's the only way to correctly charge an R134 system. Check your local repair shops and make sure they have the machine to perform the work.
#4
Reporting back, yup, I over charged the refrigerant, reduce the refrigerant, brought the low pressure side pressure from 90+psi down to 35 psi, compressor clutch engaged and now it is blowing cool air. Today is 95 degree temperature, can't imagine stuck in traffic without A/C. Speak of, I'd never own a car, new or used, that has "ice cold" A/C. People in my office building always keep complaining the HVAC is too cold, have to wear a sweater or a light coat (especially women), but I had never experienced car A/C that cold, is car A/C capable of being that "cold"?
#5
Reporting back, yup, I over charged the refrigerant, reduce the refrigerant, brought the low pressure side pressure from 90+psi down to 35 psi, compressor clutch engaged and now it is blowing cool air. Today is 95 degree temperature, can't imagine stuck in traffic without A/C. Speak of, I'd never own a car, new or used, that has "ice cold" A/C. People in my office building always keep complaining the HVAC is too cold, have to wear a sweater or a light coat (especially women), but I had never experienced car A/C that cold, is car A/C capable of being that "cold"?
I think the compressor can get shut down when the system is either over- or under-charged, which explains what you've been experiencing.
Your fix is probably only temporary. I have done this myself (add refrigerant without a proper flush/evacuation/charge) when pressed for time. The first time works pretty well and persists for maybe weeks or months. After that it's less and less effective. All this quick and dirty charging has probably introduced moisture and other crap that will inhibit cooling performance.
The good news is that it *seems* as though you are holding the charge for long periods, which hopefully means no leaks.
As the others said, the correct solution is to evacuate and recharge the system. A flush is optional and opinions are divided as to whether it's a good idea. You can do all this yourself if you want. Look on Amazon or HarborFreight for cheapo AC Manifold Gauge Sets (and flush kits). Nice to have if you're interested in doing this again sometime on other vehicles.
Otherwise, just pay the nice man to do it. He has the pricey equipment and the correct specs. And you are never supposed to intentionally release refrigerant into the atmosphere (even though R134a is pretty benign compared with the old R12).
#6
it's capable. if done right.
my 97 get's cold.
at my job the other day it was hot out i had people with 05's chevy's, lexus, doges.
they blow out cold air as soon as you press the gas.
my friend came by because his power was out at his house and HE LOVES A/C.
so he offered to put $20 in my tank and he waited in my car for 2 hours while i was at work.
andi was thinking: "if there cars are blowing out cool air at idle i can imagine what mine is doing".
to my surprise it was ice cold.
my 97 get's cold.
at my job the other day it was hot out i had people with 05's chevy's, lexus, doges.
they blow out cold air as soon as you press the gas.
my friend came by because his power was out at his house and HE LOVES A/C.
so he offered to put $20 in my tank and he waited in my car for 2 hours while i was at work.
andi was thinking: "if there cars are blowing out cool air at idle i can imagine what mine is doing".
to my surprise it was ice cold.
#7
Your fix is probably only temporary. I have done this myself (add refrigerant without a proper flush/evacuation/charge) when pressed for time. The first time works pretty well and persists for maybe weeks or months. After that it's less and less effective. All this quick and dirty charging has probably introduced moisture and other crap that will inhibit cooling performance.
The good news is that it *seems* as though you are holding the charge for long periods, which hopefully means no leaks.
As the others said, the correct solution is to evacuate and recharge the system. A flush is optional and opinions are divided as to whether it's a good idea. You can do all this yourself if you want. Look on Amazon or HarborFreight for cheapo AC Manifold Gauge Sets (and flush kits). Nice to have if you're interested in doing this again sometime on other vehicles.
Otherwise, just pay the nice man to do it. He has the pricey equipment and the correct specs.
The good news is that it *seems* as though you are holding the charge for long periods, which hopefully means no leaks.
As the others said, the correct solution is to evacuate and recharge the system. A flush is optional and opinions are divided as to whether it's a good idea. You can do all this yourself if you want. Look on Amazon or HarborFreight for cheapo AC Manifold Gauge Sets (and flush kits). Nice to have if you're interested in doing this again sometime on other vehicles.
Otherwise, just pay the nice man to do it. He has the pricey equipment and the correct specs.
And you are never supposed to intentionally release refrigerant into the atmosphere (even though R134a is pretty benign compared with the old R12).
#10
My ac in my i30 is working really great for a r134a. the old r12 systems were way better.
I used the same air condition with r134a and r12, its my 89 nissan truck, and its not even a comparision.
That AC compressor sucks.
I used the same air condition with r134a and r12, its my 89 nissan truck, and its not even a comparision.
That AC compressor sucks.
#11
you jumped the compressor ?? your car knows when to turn the compressor on if there isnt enough in the system its a fail safe for it NOT to turn on. trust me the can is under pressure and when there is enough the compressor will start to "jog" on and off till it sucks enough into the system to run constantly. If you heard a pop you prolly blew the high pressure line. the green dye is in new cans of R-134a to detect leaks...my advice. go to a mechanic before you break something else or get a buddy that knows cars. high pressure lines are nothing to mess with.
#12
1999 A/C stopped cooling
I have read the stories and suggestions in this thread. Interesting.
My 99 maxima stopped cooling a few months back and I am looking for a good to way analyze what is wrong.
Also, the cooling didn't suddently stopped. It started blowing less and less cold and gradually ended up not cooling at all.
To me the gradual loss of cooling indicates some leak in the system. Which means, if I put a can or 2 of regrigrant, it would work for some time and then will stop cooling again.
I intend to do that and then check for leaks using UV light.
I want to know if anyone else had similar failure. What did they do and where was the leak found.
I have also heard that the evaporator is the most common component for leaks in a car that had A/C working for over 11 years.
Any comments / suggests?
Thanks
My 99 maxima stopped cooling a few months back and I am looking for a good to way analyze what is wrong.
Also, the cooling didn't suddently stopped. It started blowing less and less cold and gradually ended up not cooling at all.
To me the gradual loss of cooling indicates some leak in the system. Which means, if I put a can or 2 of regrigrant, it would work for some time and then will stop cooling again.
I intend to do that and then check for leaks using UV light.
I want to know if anyone else had similar failure. What did they do and where was the leak found.
I have also heard that the evaporator is the most common component for leaks in a car that had A/C working for over 11 years.
Any comments / suggests?
Thanks
#13
There are several issues that people overlook when diagnosing the 4th Gen Maxima AC system. You should not simply add refrigerant when there is a decrease in performance. Sure, leaks do occur, but there are other things to check as well. Look to see if the compressor clutch is engaging. Also, low refrigerant charge is only one of many reasons the AC system blows cool or warm air. The best way to tell what is going on is to put a set of AC gauges on while it's running. A lot of times the static pressures will be fine. With the AC running though, the low side is observed to be too high, like 50-70 psi. This means the compressor has developed an internal leak and must be replaced. I have seen more than several cars with this condition. The quickest way to get in trouble is automatically "put another can in it" without knowing what you are doing.
#14
My Max's A/C is still holding up, so far, still pretty cool after a week of driving in hot days since I reduced the amount of refrigerant, so I think there is no leak in my case, glad that I didn't mess up. Thanks for all the tips, next time, I will make sure I understand before I start DIY.
#16
It is really dependent on the temp/relative humidity. Temp has a more more dramatic effect on the high side pressure. The service manual contains a chart for a range of ambient temperatures.
#17
#19
I thought the same thing. "Not quite cold enough" Living in Central FL, need A/C. So, I bought a can (w/o the gauge on it) and filled it up. Next day...HOT AS HELL. Got ANOTHER can, but with a gauge. I was running it at like 150psi or some crap. Just took needle nose pliers and let the gas out and keep checking it until I got around 45psi. Just as cold as it was before, just take a little while to get real cold.
Better than nothing around here.
Better than nothing around here.
#20
Yeah, the cans w/gauge says anything over 45-50psi (low side) is "overcharged" but I have no idea how accurate those gauges are. It even says high temps it will read higher and low temps lower. Plus when u press the can the gauge shoots up to like 70psi, not at all what it should be
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