A/C High Pressure
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Freshman User
Joined: Jul 2003
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From: Florida
A/C High Pressure
I have a 95 Aerostar with a 4.0 and dual air. The problem I have is as follows. Very slowly the AC has been blowing warmer and warmer to a point where it only puts out about 55 to 60 degree air in both the front and rear. Finally went out and bought a gage to check the pressure and found that the pressure on the low side is about 85 to 90, well into the red zone. The compressor does not shut down and both low pressure lines are cold and produce a sweat. Also lots of water runs out under the van at both front and rear. Can anyone out there point me to the problem and possibly a fix? Any help is greatly appreciated. Hot in Florida.
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Freshman User
Joined: Jul 2003
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From: Florida
Thanks for the quick reply Bob. Is the valve on the compressor or in the line? Can it be replaced or does the compressor have to be replaced? And Mike, the 95 Aerostar does not have an electric fan. Thanks for the input. We all learn from this great forum.
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Freshman User
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From: Florida
Bob I was affraid you would tell me to replace the compressor. On the 4.0 the compressor is right on top and easy to see, but how much of a job is it to replace and does it require any special tools. Thanks again.
Postmaster
Joined: Sep 2003
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From: Southern California
I haven't had a compressor fail that way on me yet. Compressors either work or they fail by developing leaks. I'd check the fan clutch first and replace that. It sure is a lot cheaper and easier than the compressor.
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From: Florida
Thanks Cooper. Just a thought from me. At speeds about 50 MPH and ac set on max it cools to about 50 degrees, at idle about 60 to 65 degrees. Is this an indication that it could be the fan clutch and if so how do I check it?
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Postmaster
Joined: Sep 2003
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From: Southern California
Yes, that sounds like the fan clutch. I don't know of a good way to check the fan clutch. It's cheap enough that I'll just replace it. Anyway, try this. Take a BIG house fan (and I mean BIG) and blow on the radiator while the A/C is running. I bet you'll see a drop in both high and low side pressures, and the A/C will work better. If that's the case, replace the fan clutch.
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From: Florida
OK Copper, spelled you ID wrong last time. Sorry about that. Got the fan out and set it in front of the van as close as possible. Running at idle the psi went down to about 73, with the engine reved up it was between 68 and 71 psi, about a 10 psi drop. Do you think that was significant enough to change out the fan clutch?
Postmaster
Joined: Sep 2003
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From: Southern California
I'd change the fan clutch in that case. Just to be sure, turn off the engine after it has reached operating temperature. Then turn the fan by hand, You should feel lots of resistance. If there is no resistance, the fan clutch is bad. Also, the 3.0L has left-handed thread on the fan clutch and the 4.0L has right-handed thread. So, be careful about that.
On a different note, the plastic fan blade on the 4.0L engines has a tendency to crack around the fan clutch. Watch out for that too.
On a different note, the plastic fan blade on the 4.0L engines has a tendency to crack around the fan clutch. Watch out for that too.
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Joined: Apr 2001
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In lieu of using the fan, you can also get a garden hose and continuously spray a fine mist of water through the grill onto the A/C condensor (looks like the radiator, only thinner.) If you get a cooler air flow from the vents then the fan clutch is bad or the condensor itself is plugged either internally or externally with bugs, leaves, etc. It is unusual to accumulate enough road debris to clog the condensor as airflow through the grill tends to blow off such accumulations.
If you had the system recharged before this began, it is possible the system is overcharged. This produces the same effect as undercharging - poor cooling. If someone has dumped a few cans of refrigerant into the system without using a gauge, this is a good possibility. Hope you get it figured out.
If you had the system recharged before this began, it is possible the system is overcharged. This produces the same effect as undercharging - poor cooling. If someone has dumped a few cans of refrigerant into the system without using a gauge, this is a good possibility. Hope you get it figured out.
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Joined: Jan 2003
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From: Durham, NC
Frank, do you have a way to check the head (high side) pressure? If it is very high, then I agree you have a over-charge, or a condensor air flow problem. If the head pressure is low, then I would say you have a compressor problem...
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From: Florida
Bob, I don't have a gage to check the high pressure side. And thanks to aerocolorado for the garden hose tip. Will try that tomorrow. Also I have owned this van for a year and a half and the system has gone down hill since then. Will also start looking around for best price on a fan clutch. Thanks guys for all your help with this.