theWalkinator

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?

njmaxseltd

iTrader: (19)

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.

grancouva2000

thats wright i think u should try the vaccume and see if u have a leak and have it fill to the propper amount.

theWalkinator

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"?

mikey66

The AC can be just about as cold as they want to design for. I had older cars that formed ice around the vents. Some would say this was a little excessive and wasteful. I think the newer cars are probably designed more carefully, with smaller lower-power compressors that don't demand less energy to run and are better sized for the application.

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).

1992maximase30

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.

theWalkinator

You are right, in one section of Nissan service manual, it mentioned that not enough refrigerant will cause the clutch not to engage, that led me to believe that I need to charge more 134a at the first place. However, in the diagnostic section buried deep in down the menu if you don't follow through, you could miss it that says if both low pressure side and high pressure side pressures are too high, one cause could be over charged refrigerant. My low side pressure reading is way too high, and high pressure side is high as well since it forced pressure relief valve opened few time.

This is a piece of totally not worthy DIY job, I called my local Firestone that I bring my car there for regular services, I was told it only costs $50 to vacuum and recharge the A/C, and I have wasted on 4 cans of 134a which are more than what the shop will charge. I just hope there is no leak.

I know it is not good, but they want me leave the car there for a day for the job, and the only day I can do that is Friday, but this week we have hot temperatures and I can't get through without A/C another 2 days and I can't use the other car that my wife needs to transport my kid. Oh, well, I will definitely have this done in the shop next time.

njmaxseltd

iTrader: (19)

Yes, if it's charged correctly.
Both my Maxima and my Exploder blow ice cold a/c.

Mistertones

My 2010 Corolla S sucks! Barely cold air coming out. My Max has much colder air flowing through.

stamar

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.

Maxima-4DSC

iTrader: (1)

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.

isambi

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

oldngivout

iTrader: (8)

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.

theWalkinator

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.

WhiteMaxima9600

Just curious what are the specs for the low/high side pressures?

oldngivout

iTrader: (8)

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.

WhiteMaxima9600

where can i check out the service manual? Is there a link?

theWalkinator

Just wondering, do the blower fan and A/C work independently?

Snellgrovia

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.

WhiteMaxima9600

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

1992maximase30

you know what the older one's when they first came out with the diy kit (which i have the hose), those gauges are the best one's.

the new one's that has plastic those are crap.
i had to damage out a few of those already.