Hi

I know one or two people have had A/C issues recently on the org. My problem is this, my A/C is not very cold. I have checked the pressure on the low side and it seems to be OK (about 40 psi). I checked the compressor and it seems to be spinning when I turn on the air in the car. The metal pipe with the tap for the low side seems to be cold but the A/C inside the car doesn't seem to be very cold. I have had this problem for a long time, since last summer, but tolerated it until recently got over 100F outside.

Another funky thing is that when I set my A/C to auto the A/C compressor is spinning (the center part - meaning it is engaged) no matter how cool it is inside the car. I thought the A/C clutch was supposed to disengage when a certain temp is hit inside the car. Not sure if this is normal, but it's not a huge deal. The not being cool is a bigger deal.

Any ideas?

 

I just know that AC in general is not cold these days. They switched from fre-on to this environmentally safe stuff, and it's just not the same anymore.

 

When replacing my compressor, and related compontents, I was told that it is a good idea to get the system evacuated and recharged. Nissan did a good job building this car, but there are still leaks somehow due to age. Costs about $70-100 shop around.

BTW: the new stuff is called R-134 and our car comes stock with it. Also, fortunately for us, it is less expensive than the R-12 that is also used by some newer cars.

 

The new 134-A refrigerant isn't as efficient at removing heat as the old R-12 was but the manufactures compensated for this by making the condenser and evaporator more efficient by increasing their surface area. The A/C in my '95 GLE is quite cold. Chilly in fact.

I haven't checked the pressure in my system but 40lbs on the low side sounds a little high. Usually the pressure and temperature are directly related meaning if the pressure is 40lbs the temp is 40* which is on the warm side. A pressure of 32 to 34lbs is normal. put a thermometer in your center vent with the temp selector on the coldest setting with the blower on high. The temp should be about 40* colder than the outside air temp.

There should not be a big difference in temperature between the two pipes coming from the condenser in the engine compartment. One should be cold and the other no quite as cold. Like a 5* difference. If one is quite a bit warmer you need a charge.

Small cans of refrigerant with the correct hose and fitting are available at just about all auto parts stores so I would buy one and add a little to your system to see if it helps. The stuff is pretty cheap and easy to add so I think its worth it to try.

Be careful if you decide to take your car in to have it checked. A/C repair shops are required by law to fix the leak before they can re-charge a system and if it needs to be re-charged it has a leak. The leak may be tiny but it is there and they will CHARGE you to find it.

 

[QUOTE]Originally posted by exhip95
[B]

exhip95 is right. Watch when recharging your system; don't overcharge it. If you do, the AC clutch won't engage, and you'll blow nothing but hot air. If this happens, release some of the pressure. I learned this from personal experience. After releasing pressure, mine worked fine. 40 psi seems high to me. Mine is around 30, and works fine. Also keep in mind that the AC will drop the temp only so many degrees, and not necessarily keep the interior at a certain level. If it is in the 100's outside, it probably isn't a reasonable expectation for the interior to be a cool 70. Atleast that is my experience. Confined space + automotive glass all around + direct sunlight = hard working AC.

 

His pressure at 40, if his gauge is correct is sort of OK. Lets assume the system pressure is correct and take a look at the air flow direction cotrol.
There are flapper doors which direct air in the HVAC unit. If his heater control door is open a touch, then some air coming out of the evaperator coils is going through his heater core. That could produce the effect he's complaining about.

When you have the system in AUTO mode, the compressor runs all the time to dehumidify the air. The only time the compressor will not run is when the outside air temp falls below freezing.

AUTO mode regulates the cabin air by changing the temp of the delivery air. If it gets to cold in the cabin, the system warms the air slightly to compensate, it does not cycle the compressor like a window A/C unit does.

Hope this helps.


Sometimes it's best to let the A/C pros take a look too.

 

Good points. I had forgotten he has the auto AC which is definitely more technologically advanced than those of us who must suffer with the manual thing. Your points make a lot of sense and should be considered.