# Air conditioning problem...



## JudgeTredd77 (Jun 6, 2003)

Hello all!

I'm having a weird problem with the A/C on my '99 Sentra (1.6). Last summer, the condensor was leaking so I had it changed. The system worked fine all summer long. That is, until this summer... the A/C was shot again and I was shocked to see that the condensor (same part that was replaced last summer) was leaking again! Luckily, it was under guarantee, so they changed it free of charge!

The problem is that now, their still isn't any cold air coming out of my car. The system is all charged up with freon and the pressure readings are perfect: no leaks! What could the problem be now? Could it be pure coincidence that the compressor now decided to stop working too? Is my mechanic screwing me? Any ideas and/or experience with a similar problem?

Let me know quickly! It's frickin' hot outside!
Judge


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## IanH (Feb 11, 2003)

JudgeTredd77 said:


> Hello all!
> 
> I'm having a weird problem with the A/C on my '99 Sentra (1.6). Last summer, the condensor was leaking so I had it changed. The system worked fine all summer long. That is, until this summer... the A/C was shot again and I was shocked to see that the condensor (same part that was replaced last summer) was leaking again! Luckily, it was under guarantee, so they changed it free of charge!
> 
> ...


If the pressures are fine the compressor must be working!
So what are the pressure readings at say idle and 2000 rpm ?
Did you get the dryer changed ? FREON breaks down with water to form acids that attack the Condenser and Evaporator. I have lost a condenser in the past due to this.

Make sure the system is vacuumed for long enough to remove the air and water. This depends somewhat on the connection and the pump but an hour would be my minium.
(I have a very large industrial pump.)

Do you have a temp gauge that you can measure the Air intake and the air coming out of the vents.

Its possible its been over charged if it is in fact all working. Again what are the pressure readings for the LOW and HIGH sides of the system, what is the ambient temp when this was recorded and at what rpm.
You are looking for numbers like say 50 -60 psi on the low side and 200 - 300 psi on the high side approx.


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## JudgeTredd77 (Jun 6, 2003)

Ok, so I picked up my car from the garage and they swear it's full on freon and doesn't leak. They suggest the problem may be the compressor. But when I push the A/C button, I hear the compressor starting up, just don't have any cold air. I don't have any instruments or guages... I'm no expert, but shouldn't the system work if it's full on freon and if the compressor works?


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## IanH (Feb 11, 2003)

JudgeTredd77 said:


> Ok, so I picked up my car from the garage and they swear it's full on freon and doesn't leak. They suggest the problem may be the compressor. But when I push the A/C button, I hear the compressor starting up, just don't have any cold air. I don't have any instruments or guages... I'm no expert, but shouldn't the system work if it's full on freon and if the compressor works?


Well No.
the system works as a heat pump. It moves heat around.
The temperature you get on the low side depends on the pressure. If the pressure is too high or the flow is restricted you will not get the cooling you are looking for.
Also download the FSM from the sticky at the top of the B14 section.
http://www.nissanforums.com/b14-95-99-chassis/60760-b14-full-service-manual.html

So try this. 
Start the car and listen for the A/C to click on. then feel the temperature of the low or return line. this runs from the evaporator (near passenger side fire wall back to the compressor.) See HA-57 in FSM
Then increase engine speed and see if it gets cooler. 
Do you get any cooling at all on the freeway at higher speeds ( maybe leave the car in a lower gear to keep engine speed up.) 
Please talk to your shop and ask them for the amount of freon in Ounces they put back in the system and the pressures they measured. Or take the car back and get the information.


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## EvilPotato (Sep 6, 2005)

do the fans kick in when you turn on the A/C? cause that's what was wrong with my A/C. I discharged the r134a and vacuumed the water and lubricant and whatever else is in there and refilled it again, adjusted the air mix door and water cock, and still no cold air. Then I looked at the FSM and in the diagnostic section for the A/C it says the fans should be on when the compressor kicks on. I replaced the burnt fuse just now and viola!


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## EvilPotato (Sep 6, 2005)

and also when i had way too much refrigerant in it there, the compressor kicks in and stays on only for few seconds and cuts off, weird huh? so look out for that.


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## mudpaws (Feb 25, 2009)

*closed link*

I didn't see any FSM there, except the ones you have to buy. It just says the guy registered his domain name. No help.


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## EvilPotato (Sep 6, 2005)

http://dl.dropbox.com/u/1645935/b14_FSM.rar


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