The A/C on my 1995 Fleetwood (great car!) stopped working a while back; compressor wasn't even cycling and so I took it in for a diagnosis.
The GM mechanic, knowing I didn't want to put hundreds of $$ into the repair at this point told me confidentially that the accumulator had hairline cracks and if I replaced it and added some R134a that it would work.
I did so and the compressor started running but only warm air still blows out the vents and a check of the low-side pressure revealed it is way too high, about 100psi.
Does anyone have any thoughts as to what the problem could be now??? I'm at my wits end!!!:hmm:

The A/C on my 1995 Fleetwood (great car!) stopped working a while back; compressor wasn't even cycling and so I took it in for a diagnosis.
The GM mechanic, knowing I didn't want to put hundreds of $$ into the repair at this point told me confidentially that the accumulator had hairline cracks and if I replaced it and added some R134a that it would work.
I did so and the compressor started running but only warm air still blows out the vents and a check of the low-side pressure revealed it is way too high, about 100psi.
Does anyone have any thoughts as to what the problem could be now??? I'm at my wits end!!!:hmm:

who put the a/c in?

are you sure its the low side? make sure you add a/c on teh low pressure port and you are checking it on teh low side which is actually right on the a/c canister thing which the hole in it.

remove the air before the system blows or worse a.s.a.p.

just make sure you added the air in the metal canister thing and that is where you are checking the pressure.


to be honest its been a while since i did mine but i dont remember if the a/c has to be on or off when you check the pressure someone on here should know

If the compressor is not running, it will show the same pressure on both sides, typically somewhat high. As the compressor kicks in, the low side will drop, and be pulled down, and the high side will build up. As the orifice is varied, or the compressor is cycled, it will attempt to control or maintain the pressure differences.

Is the compressor actually doing anything? Do you have high side gauges? They are very important, far more than the low side. If the input shaft to the compressor is broken, the compressor will appear to be running but it won't compress anything because it isn't running.

Check pressures JUST as the compressor cycles off, as they start to peak out. Remember, all doors and windows open when measuring pressures!! You must attempt to make the interior of the car as close to ambient as possible. Use the GM book for the pressures, they vary widely depending on temp and humidity.

the pressure does vary but not to more than about 50 psi max that i know of on my gauges this is for the low side

Thx for the replies so far... Before I added one pound of R134A, after installing the new accumulator, the compressor began running, whereas before it was not at all. Trouble is, now it does not seem to ever stop running, the low-side pressure is about 100 PSI, and only warm air is blowing out of the vents! Do you think I have a clogged orfice tube???

Duh, in my first sentence of my last reply I said "Before I added one pound of R134A," . I didn't mean to have the word "before" starting off the sentence!

Correct me if I am wrong, but if the orifice is plugged, I would expect low side to be very low, and high side to be very high (think of the compressor sucking on plugged up low side) and yes, it would cause insufficient cooling.

But for high low side, too much freon, no compressor working, or temps that high and low side pressure is SUPPOSED to be high, but no conditions in the FSM indicate over 55 psi (RL 60%/100 degrees F). I would speculate by the chart, that around 70 psi low side @ 100F and 100% RL.

According to my 94 Fleetwood FSM:
60% Relative Humidity (I can post more humidity's if needed, most are very close to these numbers) These prtessures are @ 2000 rpm, all doors/windows open.

Ambient Temp....Max Low Side...Max High Side...Outlet Temp F
70....................23..................200..... .............43
80....................36..................315..... .............56
90....................43..................365..... .............64
100..................55...................375..... ............78

As you can see, high side is likely more important than low side. The book says for a insufficent cooling check to start car, run at idle, set for max cooling (60F), all doors/windows open, blower on high, and then feel the evaporator inlet, or the pipe just after the orifice/expansion tube. And feel the accumulator assy.
Proper operation is if both the evaporator inlet and the accumulator are much colder than the outside air, and both are near the same temp. If the exaporator inlet tube is cooler than the accumulator assy, or frost is present on the accumulator, then low charge is indicated.

it does not stop running when you have your a/c on or off?


if your ac is on then it should never really stop running that i know of.

it should turn off once you a/c is off though.

I would just drain all the freon out of the system and add the recommended pounds to the system to be safe.

Most important it could be that the freon is either overfilled or the freon is old maybe? old freon can give hot air then again you may have another problem in your a/c system which you should have checked out.

Yup, I am leaning that it might be over filled, or the compressor not actually compressing. When the compressor is not on, the system won't accept freon well, as it is higher pressure in the system than the can, so it equalizes and doesn't move.

I am now completely stumped! Before with the supposedly cracked accumulator the compressor was not turning/running at all ever. Now that I installed the new accumulator and added 1 pound of R134a it never stops running, no matter if the A/C is turned on or not, only warm air blows from the vents, and the low side pressure (checked right at the accumulator inlet valve) is about 100 psi!
Any ideas on what the hell is going on?!?!

I am now completely stumped! Before with the supposedly cracked accumulator the compressor was not turning/running at all ever. Now that I installed the new accumulator and added 1 pound of R134a it never stops running, no matter if the A/C is turned on or not, only warm air blows from the vents, and the low side pressure (checked right at the accumulator inlet valve) is about 100 psi!
Any ideas on what the hell is going on?!?!

just take it to a local a/c shop not the same one you took it to because they dont seem to be too good and then just have them diagnose it.

It's way to difficult to diagnose over the net and no one around here is an a/c expert.

It sounds as if maybe a bad orifice tube... Just a stab in the dark but judging from your pressure.

Just curious, but how does the accumulator feel after a few minutes of operation? Should feel pretty cool. If its hot (which i'm guessing it might be) feel down the lines and see if it gets cold suddenly somewhere.

That's another perplexing thing about this whole deal: the accumulator doesn't feel hot OR cold and neither do any of the lines going into/out of the evaporator or condensor! I guess I'll have to give up and take it into the Caddy dealer and get hosed by their rates!

It sounds like the compressor isn't compressing, that is why the pressure is high. It is normal to be high at that time. Turn the car off and watch the gauge, turn the car on and watch the gauge (with the compressor on, look for the front to be spinning and you will heat it CLICK when you engage it from the dash) the pressures won't change if the compressor isn't compressing. Just because it is spinning doesn't mean it is compressing, I know, I had a Ford 4.0L that broke the input shaft and did that to me.

Still not sure but I think you may be right about the compressor spinning but not actually compressing; it never seems to cycle off, etc. I guess I'm in for a high $$ repair!