A/C for 2002 Maxima
08-02-2005, 11:34 AM
#1
A/C for 2002 Maxima
My Max is not blowing cold air anymore...its slightly cold at best. Leaving the Auto Temp setting on 73, the Max keeps the fans at FULL trying to get the cabin cooled (this is in 91 degree heat).
I guess I'll go by and get a can of R134A from Advanced Auto. Does anyone have a write up? R134A systems must be in the exact pressure range.
I guess I'll go by and get a can of R134A from Advanced Auto. Does anyone have a write up? R134A systems must be in the exact pressure range.
08-02-2005, 12:52 PM
#6
Supporting Maxima.org Member
Join Date: Dec 2004
Location: Lakeland, FL
Posts: 1,587
i dont have a write up, but i have an EPA 609 and an ASE cert in a/c 
basically, if you have a low charge, you have a leak. you need fo find the leak and fix it, then charge the system
turn the compressor on max a/c and take a look at the compressor clutch and tell me what its doing (cycling, etc.)...
and well go from there.
basically, if you have a low charge, you have a leak. you need fo find the leak and fix it, then charge the system
turn the compressor on max a/c and take a look at the compressor clutch and tell me what its doing (cycling, etc.)...
and well go from there.
08-02-2005, 02:18 PM
#7
Excellent! Thanks Bewts.
With the car running. The fans and compressor kick on and stay on. After about 3 min, the air is as cold as it will get (sorry, no thermometer) but the fans and compressor remain on.
With the car running. The fans and compressor kick on and stay on. After about 3 min, the air is as cold as it will get (sorry, no thermometer) but the fans and compressor remain on.
08-02-2005, 06:45 PM
#9
Hi Bewts,
Yup, the ac kicked on and stayed on. I added some oil/R134a to the system (just a little) and got it to cycle. The guage shows it drop to 25 psi when the AC kicks on and then go up to 45 psi when the AC shuts off but it is no cooler inside than it was.
Yup, the ac kicked on and stayed on. I added some oil/R134a to the system (just a little) and got it to cycle. The guage shows it drop to 25 psi when the AC kicks on and then go up to 45 psi when the AC shuts off but it is no cooler inside than it was.
08-02-2005, 07:44 PM
#11
It was on for about 3 sec then off for about 10 (added a bit to much). Cycled some out of the system and it runs without kicking off but the pressure is 25 psi while on (shut off the AC and it goes up to 45 psi). Im going to take it to my mechanic tomorrow. This kit doesn't come with a high side guage, so there may be something trapped in the orifice.
08-03-2005, 08:11 AM
#12
Supporting Maxima.org Member
Join Date: Dec 2004
Location: Lakeland, FL
Posts: 1,587
unlikely, though possible.
its probably a leak, youll know when the rest of the refer leaks out, or when your mechanic tells you.
id just buy a leak detection UV kit and go from there.
hope the damage isnt that bad
its probably a leak, youll know when the rest of the refer leaks out, or when your mechanic tells you.
id just buy a leak detection UV kit and go from there.
hope the damage isnt that bad
08-04-2005, 07:25 PM
#14
Supporting Maxima.org Member
Join Date: Oct 2002
Posts: 109
On the 02/03 Maximas, the a/c compressor is not supposed to cycle. That is true for both the regular and the automatic a/c systems. It is a variable displacement compressor that modulates its capacity according to the suction pressure. On an ATC system like you have, if the "auto" light on the controller is on and the outside temperature is above 23F, the compressor should be running without cycling. The compressor will cut out if the condenser pressure is too low (indicating an empty system --> leak) or too high (one or more of overcharge, a high-side blockage somewhere, inadequate condenser air flow, or extremely high ambient temp) or under a few other conditions (engine stalled or about to stall, throttle floored, etc). Basically, with the a/c system on "auto" and the car idling, the compressor should run all the time unless the weather is well below freezing.
If you added refrigerant and the compressor was running all the time before but is cycling now, then likely it is now overcharged. The very short cycling you report, and normal evaporator pressure when the compressor is on, are consistent with overcharge. You might also hear the radiator fan switching to high speed shortly after the compressor clutch pulls in, due to the abnormally high condenser pressure. It is too late now but you should have started by checking whether the compressor discharge line was hot where it enters the condenser and the suction line cold where it comes out of the firewall. If they were, then your problem is likely with the control unit or one of its temperature sensors. If they were not, only then would you suspect a refrigeration problem. (On a cool day, the compressor discharge line might not be hot, but on a 90 degree day it should be too hot to hold your finger on it.)
If you have overcharged the system, your only real recourse at this point is to take it to a shop with the equipment to evacuate it and refill it.
Once you get that taken care of, if you still have the problem you might want to search around on the forum for one of the writeups on the self-test for the control unit. This ought to help in identifying a bad temp sensor.
BTW one other simple thing to look at: have you replaced the cabin filter? If you have never replaced it then the problem might simply be that it has become clogged and the air flow over the evaporator is too restricted to cool the car. If that were the problem, though, then the air discharged from the vents would be cold.
Good luck with it.
If you added refrigerant and the compressor was running all the time before but is cycling now, then likely it is now overcharged. The very short cycling you report, and normal evaporator pressure when the compressor is on, are consistent with overcharge. You might also hear the radiator fan switching to high speed shortly after the compressor clutch pulls in, due to the abnormally high condenser pressure. It is too late now but you should have started by checking whether the compressor discharge line was hot where it enters the condenser and the suction line cold where it comes out of the firewall. If they were, then your problem is likely with the control unit or one of its temperature sensors. If they were not, only then would you suspect a refrigeration problem. (On a cool day, the compressor discharge line might not be hot, but on a 90 degree day it should be too hot to hold your finger on it.)
If you have overcharged the system, your only real recourse at this point is to take it to a shop with the equipment to evacuate it and refill it.
Once you get that taken care of, if you still have the problem you might want to search around on the forum for one of the writeups on the self-test for the control unit. This ought to help in identifying a bad temp sensor.
BTW one other simple thing to look at: have you replaced the cabin filter? If you have never replaced it then the problem might simply be that it has become clogged and the air flow over the evaporator is too restricted to cool the car. If that were the problem, though, then the air discharged from the vents would be cold.
Good luck with it.
08-04-2005, 10:18 PM
#16
Take your car in to have eighter the expanssion valve repleaced or cleaned out. Most likely the valve has gone bad- its a common problem on a 4th gen and 5th gen Maximas. You would wanna see what the low side and high side pressures are at with the AC runing on MAX cool, recirc button on- and engine RPM at 2500RPMs. It shouldn't be any lower than around 25psi on low side and around 150 deg for high side. With the system properly charged you should see 70psi on low side on a 70 deg day at sea level- this is with the system stabilized, off for a good hour or so. Maxima AC systems are not the greatest systems in the world in terms of cooling, the condenser efficiency is not up to par, I'm suprrised Nissan didnt use a dual condenser system like a few cars do. Basically its a 2 piece condeser but its all designed to be one unit, you will have more lines going into the receiver drier but the efficiency will be much improved. On a Maxima you should NOT see the compressor cycling- since its a variable displacement compressor, one of the newer designs in AC systems.
08-05-2005, 03:42 AM
#17
Good info imjd. The system did start cycling when my less than adequate guage showed it was too high. I evacuated the system down to 35 - 40psi and the compressor remained on.
Yesterday I bought a small thermometer to read the temps. In the morning, at app 72 degrees, on AUTO and RECIRC the car put out 44 degrees. In the afternoon, at app 95 degrees, the car held 50 degrees on AUTO and RECIRC. I stopped by a pet store for about 15 min, came out and the car took 3 miles to get the temp at the vents to 60 degrees...then held it there till I got home.
I'll mention the expansion valve this morning when I see my mechanic.
Yesterday I bought a small thermometer to read the temps. In the morning, at app 72 degrees, on AUTO and RECIRC the car put out 44 degrees. In the afternoon, at app 95 degrees, the car held 50 degrees on AUTO and RECIRC. I stopped by a pet store for about 15 min, came out and the car took 3 miles to get the temp at the vents to 60 degrees...then held it there till I got home.
I'll mention the expansion valve this morning when I see my mechanic.
08-05-2005, 07:22 AM
#18
Supporting Maxima.org Member
Join Date: Oct 2002
Posts: 109
[Bewst]
TXV, as far as I know. With a variable displacement compressor, suction throttling is not needed. Sorry to step on your reply a little bit there, but I realized you were on the wrong track when you told 2002 to look for the compressor cycling.
[2002] 35-40 psi is probably a little high for the evaporator pressure when the system is running, but it is hard to say for sure because where the pressure actually settles depends on a lot of factors such as engine speed, dry bulb temperature, humidity, evaporator air flow, and more. Also if you have managed to introduce some air into the system the pressure will run high. And, it may still be overcharged.
Is the suction line cold? If it is covered with condensation (but not frost) then odds are your problem is somewhere else. Be careful of expecting too much from the system. I live in an area that's not as hot as hot and humid as yours, as far as I know my car's a/c works correctly, and in my opinion it does not have sufficient capacity for hot, humid weather, especially during stop-and-go or local driving.
IMJD, are we runninng a txv or h-valve or what?
[2002] 35-40 psi is probably a little high for the evaporator pressure when the system is running, but it is hard to say for sure because where the pressure actually settles depends on a lot of factors such as engine speed, dry bulb temperature, humidity, evaporator air flow, and more. Also if you have managed to introduce some air into the system the pressure will run high. And, it may still be overcharged.
Is the suction line cold? If it is covered with condensation (but not frost) then odds are your problem is somewhere else. Be careful of expecting too much from the system. I live in an area that's not as hot as hot and humid as yours, as far as I know my car's a/c works correctly, and in my opinion it does not have sufficient capacity for hot, humid weather, especially during stop-and-go or local driving.
08-05-2005, 08:18 AM
#19
I went in this morning. The low side was fine but the high side was around 200 psi (no air in the system). They emptied the system then put a vaccuum on it. Refilled to 1.1pds and the readings on low/high were perfect.
After testing, he had me come back and we chatted for a bit. Great place in Raleigh, PM if anyone wants to know. He put a sniffer all over the system and found what appears to be a leak where the two metal lines go into the compressor near the front of the car.
Since the compressor was hot, he advised me to wait until it is cool, then try some soapy water and see if any bubbling occurs or bring it back and he would do it.
He checked the needle on the low side to see if it flucuated, indicating an expansion valve problem. It moved very little. He said it still could be a problem, but would have to see how it does today in the hot temps (this morning it was around 80 in his shop).
So it looks like I have a leak, but probably pretty tiny. He surmised that I had .8 pds in the system then filled it up a little to high. The low charge probably caused my cooling to be off by what I noticed...slightly warmer over time. Note to self, just take the car in for AC problems. Do not try to fill with the stuff from the auto stores, there is no way to know how it affects the high side. He said they've had folks come in running psi so high on the high side he shields his face while working on it.
After testing, he had me come back and we chatted for a bit. Great place in Raleigh, PM if anyone wants to know. He put a sniffer all over the system and found what appears to be a leak where the two metal lines go into the compressor near the front of the car.
Since the compressor was hot, he advised me to wait until it is cool, then try some soapy water and see if any bubbling occurs or bring it back and he would do it.
He checked the needle on the low side to see if it flucuated, indicating an expansion valve problem. It moved very little. He said it still could be a problem, but would have to see how it does today in the hot temps (this morning it was around 80 in his shop).
So it looks like I have a leak, but probably pretty tiny. He surmised that I had .8 pds in the system then filled it up a little to high. The low charge probably caused my cooling to be off by what I noticed...slightly warmer over time. Note to self, just take the car in for AC problems. Do not try to fill with the stuff from the auto stores, there is no way to know how it affects the high side. He said they've had folks come in running psi so high on the high side he shields his face while working on it.
08-05-2005, 10:27 AM
#20
Supporting Maxima.org Member
Join Date: Dec 2004
Location: Lakeland, FL
Posts: 1,587
and 8lbs is a bit too much IIRC 
no... no problem at all, if you see that im mistaken, please, by all means correct me. im picking up my 5.5gen this weekend so i havent had a chance to run through it yet. theres still a bit to learn. i appreaciate the info.
Originally Posted by imjd
TXV, as far as I know. With a variable displacement compressor, suction throttling is not needed. Sorry to step on your reply a little bit there, but I realized you were on the wrong track when you told 2002 to look for the compressor cycling.
no... no problem at all, if you see that im mistaken, please, by all means correct me. im picking up my 5.5gen this weekend so i havent had a chance to run through it yet. theres still a bit to learn. i appreaciate the info.
Thread
Thread Starter
Forum
Replies
Last Post
Nintensity
5th Generation Maxima (2000-2003)
9
08-13-2015 05:41 PM
yat70458
5th Generation Maxima (2000-2003)
2
08-03-2015 01:16 PM