My AC works great for about the first 30 minutes. Then it slowly gets warmer. I turn the temp down to 65 F and the fan just blows more, but the temp is not as cold. Still colder than without the AC on. If I switch to Econ, it starts blowing cold for about 3 minutes then warms up. If I leave the AC off for a while then turn it back on, it blows very cold again. I just hate switching from AUTO to ECON all the time to keep the car cold on a 90 F day.

The car drips a lot of water when the AC is running, more than I am used to seeing with any other car. I got the car last fall so I don't know how long it has been doing this. It has about 175,000 miles on it.

The Engine temp does not change when any of this happens, it always stays just a little under half way.

Does it need recharged?

 

no you got water in your ac system.. it freezing up your valve at evaprator... u need to take it to a shop where they have ac machine and have them vaccum out water from your system. that should fix it ...

 

Thanks. I hope it will not be very $$$. How would water get in there in the first place? How could I keep it from happening again?

 

Water doesn't get into an A/C system.

Have the system serviced.
Either your low on refrigerent or the pressures are not correct.

 

just take it to a oil change shop that services a/c's... econ mode is for heating purposes i think, well at least the owners manual says so.

 

97green is right. Over time, a/c systems have a tendency to get moisture in the system which is why it should be serviced regularly. When the refrigerant goes through whatever metering device it has with moisture in it, it will freeze up at the metering device before the evaporator. Having your system serviced should fix your problem.

 

Thats BS. Water doesnt acculmulate in the AC lines unless theres a leak, in which case it wouldnt be working at all. The problem could be low refrigerant pressure causing the suction(low side) line to freeze up, or the condenser fan motor is going out and so the compressor is shutting off due to high head pressure. Definitely see a service shop.

 

Really. Well then explain what the purpose of a reciever dryer or accumulator is. The main purpose of them is to trap moisture using a desiccant. Get your facts straight.

http://www.id-usa.com/how_to_ac.asp

 

We will find out tommorrow what it is. I will take it to the shop right next to my work. I agree, I think SOMETHING is freezing since it does it when I have the AC WFO (wide F$#Kin' open). Then switch to econ and it slowly starts getting warmer. Switch back, and you can keep beer cold in the car for about 30 minutes. It blows very cold air. Then slowly gets warmer.

Thanks for the input. I will tell you what I found out.

 

I hate to quote peoples own **** but..." The primary functional difference is that the accumulator is designed to prevent liquid refrigerant from being drawn into the compressor." Last line of the the Reciever Dryer or Accumulator section. I was referring to water accumulating INSIDE the lines. Its a sealed system. Any water moisture shouldve been removed before refrigerant was added to the system.

 

My mechanic is swamped and said to check the high and low pressure. He didn't think it was low on R-134a since it blows very cold most of the time.

I checked the pressure today and got 150 psi on the high side and 34 psi on the low side at idle and 180 psi on the high side and 34 psi on the low side at 2000 rpm. The high side pressure slow increased to 200 psi and the low side dropped to 30 psi after about 2 minutes at 2000 rpm. I am guessing it slowly changed due to the increase in temperature of the engine bay. It was about 70 F outside and 60% humidity. From searching, the pressure should more than that on the high side, right? Do I need a new compressor?

I ran the car for 10 min on AUTO, recirc on,windows down, set at 65 F with the fan on high before testing. A/C was blowing very cold the whole time. The lines were extremely cold with condensation on them.

I could not get the car to act up. I need to test it at 70 mph on the highway, then it will act up. Just a little hard to read the gauges!

 

Any suggestions? New compressor? Recharge?

 

I'll check my notes and get back to you. I'm pretty sure the high side is supposed to be around 200 psi at 2,000 rpms and 30 psi on the low side but i'll double check.

 

If youre doing this while the car is parked and running, have a fan nearby blowing on the condenser and see if you notice a difference. Occasionally if the high side pressure is high like that its not getting enough airflow across the coils. Also, how do the fins look on your condenser...beat up, dirty?

 

I just looked at the condenser. It is pretty beat up where the air opening in the bumper is. Could that be my problem?

 

It will make the high side pressure a little higher. Still live-able but it could be a problem on hot days. You can either replace the condenser coils which you would have to shell out money for, or you can get a fin comb and straighten them out. You might get lucky and find a fin comb at Home Depot but I havent looked for them there. If there is a Commercial/Residential HVAC supply shop nearby you should be able to buy one from there without needing a contractors license. Otherwise another alternative would be to use a small flat-head screwdriver and straighten the fins manually. It'll take time that way but you'll be able to clean them off and and the coils will cool more efficiently.
(long post, sorry)

 

Thanks for the info, I will staighten the fins out the best I can and see if that helps.

 

Well you have been getting some good info. The problem is with the Expansion valve. The valve is sticking closed and blocking the flow of freon, it could be from moisture in the system, debris from a failing compressor or the drier is coming apart. Here's the fix, evac the system. Replace the expansion valve and drier. Vac the system and recharge. I would bet that the drier has failed and there are little bits of drier floating around the system. Hopefully the new drier will filter and trap any junk floating around after repairs.

 

feel free to flame me to death for my statement here, but if you have the automatic climate control, isn't it supposed to adapt to the cabin temp. once it is set? say, you ahve it at 60, and the car gets colder than 60 because it blows cold as hell, shouldnt the temp sensor built into the climate control activate the fan for heat to get the temp back to indicated?

i have manual controls, but my brothers maxima had auto climate control and it did this all the time, even when he had it new.

 

I won't flame you.

My AC works great keeps the cabin at the right temperature for about 45 minutes on a hot day. It adjusts as needed to keep the cabin at the right temp. Then after about 45 minutes it slowly warms up. The fan starts speeding up but the air coming out of the vents is not getting colder. I switch to ECON (AC off) for about 10 minutes and then switch it back to AUTO (AC on) and it works great again.

I will straighten the fans first. If that doesn't fix it, I think z32drifter is probably right.

 

Let's bump this. I usually have my windows open in the summer time, and coming back from Canada was the first time I wanted to put on my A/C. The problem is, it was set to 65 degrees, and NEVER got cold. It wasn't hot air coming out, but it certainly wasn't cold. Is this problem different from the problem the original poster was explaining? If so, what needs to be fixed?

 

My money's on one of two things.
1) Faulty expansion valve. This seems to support your pressures suddenly becoming higher on the high side and lower on the low side.
2) Compressor swash plate angle not changing, causing evaporator freeze-up. This is much less likely, but if the lower evaporator pressure is not causing the compressor's swash plate to change, it means the compressor would still be working at full displacement (full blast essentially).

I would agree with most others though that the expansion valve is either clogged or malfunctioning. If you have never opened the system before, it's most likely a malfunction. Sounds like at full blast that your compressor itself is doing a good job though.

BigLou93SE - you have a different issue. Most likely a leak or failing compressor. Hopefully just a leak. Have it tested by a shop and they'll let you know.

 

probably low on gas causing the evap to freeze and reduce air flow