Confusing A/C Problem
 

So earlier this summer, about a month ago I had to recharge my A/C unit on my 1997 Accord because the air was not cold enough. It worked fine and the A/C has been cool for about the last month.

Today the A/C stopped working and is blowing regular warm air. Here is what I have gathered so far about the problem.

-When the A/C is turned off, the coolant pressure gauge (connected to the low end) reads that there is the proper amount of coolant in the system.

-When I turn the A/C on and take the reading the gauge reads that there is zero pressure in the system.

-When I turn the A/C on, I can still here both the cooling fan turn on and the compressor click on initially.

-There is also a slight hissing sound coming from under my glove compartment area in front of the passenger seat, however that sound started in the beginning of the summer.

Anyone have any ideas on what the problem could be. I have also checked all fuses and they all seem to be unbroken. Thanks.

When you turn on the A/C, the low side pressure is being sucked into the compressor.
It can even go into vacuum if you had a real set of gauges to view.
Consider that the system was already low on freon once before, meaning freon leaked out somewhere.
So now it is low on freon again, meaning the leak did not fix itself. LOL
Look around line fittings for oil seepage and also unplug the pressure switch and check in there.
The oil bonds with the freon so where ever the freon leaks there will be oil seepage.

Thanks. So even if all the coolant has leaked out, the pressure can still read as full (on the low side) when the A/C is turned off?

By the way, you can go to AutoZone and buy a can of Leak Dye and a pair of those funny looking glasses they have , and find your leak ...

Might want to pick up another can of freon with stop leak and oil already mixed in with it...

WheelBrokerAng :)

Thats what I was planning on doing. Earlier this summer I refilled it with just 134a with no leak seal. The summer before that I use the coolant with leak seal and it stayed full for a whole year.

I just wanted to be sure that it was normal for the A/C pressure gauge to read as full when the A/C is turned off. I don't want to risk putting to much coolant in and over-pressurizing the system.

The car has had a slow leak of A/C coolant for a few years now (usually requiring 1 can of 134a at the beginning of each summer), this is just the first time it has drained so quickly.

Just watch your gage and you wont be over filling it at all..:)

But is it normal for the gauge to read as full when the A/C is turned off, and empty when the A/C is turned on?

The best thing is to get a real set of gauges, like HondaDude said. You have to watch both the high & low sides, to tell the difference between a leak here or there, vs. a plugged expansion valve, vs. other problems.

OK, but under normal circumstances if the freon has leaked out, will the pressure still read as fine when the A/C system is not in use (turned off).

evac and recharge the system,leave under a vacc foe at least 30 minutes , add 1 lb of r134-a and some dye, DO NOT add any sealant in the a/c system it will plug up the expansion valve.....

the pressures you are reading on the gauge ,, if the high and low side about the same ?? it might be stabilizing pressures due to ambient temperature ..