GRAND_LS 4

iTrader: (2)

Alright, my A/C hasnt been cooling too well in this weather of ours. So I went out a bought a pressure gauge, plugged it into the Low pressure socket, started the AC on full blast and got a reading close to 55PSI.

However, The A/C is still not very cold during the day; it takes a long time for it to cool. Its only truly cool when it’s raining or at night.

What do you think might be causing this?

What should the PSI be on the LS? is the 55PSI the reason why its not cooling enough? is it too high?

Thanks guys.

GRAND_LS 4

iTrader: (2)

Oh yes, I just thought about the cabin filter, its not that old (its still very clean), but Im going to change it anyways.

Any other reasons?

gserep1

It is either overcharged, or your compressor is not operating efficiently. Are you sure your compresor clutch is engaging?

Plug in the low side gauge, and see what the reading is on the low side when the compressor is not turning. The value should be HIGH, because the presures on the low and high side shoujld equalize in a few minutes after being turned off..

When you start the compressor, the low side will go down normally to about 25-27, and the high side should go up to around 140 to 180 depending on how hot is in outside. The discharge line (small line) should be HOT to the touch, and the big sized low side line should be very cold to the touch. If the low side pressure does not drop below 55, either the compressor is not turning, or the system is overcharged. Make sure that the electrical system of the AC system is operating correctly.

Keep in touch, and good luck.

ychachad

Grand LS,
55 psi is too high on the low side. Dangerously high, in fact. You can multiply that pressure several fold on the high side, and blow a line or the compressor. The max you want is about 45 psi.
Why did you charge it? Because it was leaking? Fix the leak first, then charge it. you may have to vaccuum it first before fixing the leak.

GRAND_LS 4

iTrader: (2)

Thanks a lot for your help guys. After I read the gserep1's post, I went ahead and recorded some number. The outside temperature was 91F

The Numbers are the following: (I let the car warm up before engaging the compressor)

Max fan speed w/compressor ON - 65PSI (Air was not cool)
10mins later, it gradually dropped to 55PSI after a while (a bit cool)

10more minutes later I turned down the fan speed to Lowest:
Low fan speed w/compressor ON - 35PSI it was cool

Back to Max fan speed w/compressor ON - 55PSI

Max fan speed w/compressor OFF - 100PSI (then after I turned on the compressor, it went back to 55again)

I couldnt get any readings for the High side because the socket was a larger then the Low side, and wouldnt fit my gauge.

ychachad- I never said I charged it, I only bought a gauge, I've never charged or touched the A/C system since I bought the car

GRAND_LS 4

iTrader: (2)

So now, should I release some of that pressure? would that help? and whats the best way to go about it?

gserep1

Feel the two lines coming oout of the compressor. The big line is the suction line and should be cold, and the small line is the discharge line, and should be very hot with the compressor running. Be careful touching this line as you can get burned.

If the small lines are not hot, then the compressor is not pumping much and is going bad. If the line is extremely hot, it is overcharged, and some needs to be drained out.

The big line should be really cold, but I have a feeling that it is not as cold as it should be. The combination of not too hot discharge and not too cold suction line points to a weak compressor.

They DO make a high side line for the discharge side. the lines are purposely different sizes to prevent putting gas in the high side, and subsequently blowing up the bottle used to charge the system. This is very dangerous. So with theproper equipment, each line goes only on the right line.

If the uit is overcharged, it is possible that the system is near the cutoff pont for the high side. Each side has a safety switch to prevent damage. The low side switch opens if freon level drops too low, and the high side cutout switch turns off the compressor if discharge pressure gets too high.

Try this and get back to us.

GRAND_LS 4

iTrader: (2)

When I mentioned a bit cold, or not too cold, I was talking about the Air from the vents, not the actual lines.

The lines were exactly how they are supposed to be, one is really hot, and one is really cold.

Im going to try and let it out, and see what happens. I'll let you guys know what happens, thanks a lot for the help