AC Problem

[photog3740]

I have 1999 Eddie Bauer. The AC is not working very well.
I thought it was the blend door, which ended up not being broken. I did replace it via the plenum. The actuator is working correctly. The refrigerant is full.
The AC will be cold, then get warm and then hot. Max AC doesn't help. If I turn off the AC, wait awhile, turn it back on, sometimes it will be working correctly.

What else could it possibly be? Summer is coming, so I need it to work.
Any help here is GREATLY appreciated!!!!!!!!
Thank you!

 

[fixt]

So, what is the compressor doing while this is happening?
How do you know refrigerant is full without gauge readings?
It would help to know.

The static system pressure reflects ambient temperature, and is the same on both sides of the system high and low. When the compressor starts, the low side pressure will drop to something around 35-40 depending on temperature and high side pressure will increase, that's compressor discharge pressure and is the liquid side. If the pressure drops too low the low pressure switch will turn off the compressor until pressure rises above its trip, somewhere around 24-28 but it varies.

The following is a guess.
Your system starts up and gets cold, and the compressor then trips on low pressure due to lack of R134a.

A gauge set will tell you this. The charge port is on the top of the condenser on the passenger side next to the firewall. The low pressure switch is just below the port.
A qiuckie charge kit will probably get you there, but don't use one of stop leak kits. They usally destroy AC and a reputable shop won't attach their expensive machine to it if they know its in there. Be advised that the gauge on the quickie kits are not very accurate. Its better to perform real repairs if needed than applying a band aid fix.

Based on the info provided, it sounds like the system is just low. The static pressure won't tell you much other than there is some R134a remaining in the system; that static pressure will reflect ambient temperature.

Gauge sets are not very expensive and will save you a great deal of money. Its well worth the time invested to learn how to use one and the basics of the AC system.

But please don't use the stop leak stuff.

 

[photog3740]

Hi there,
Thanks for responding. I do have gauges, Yellowjacket brand.
I hooked them up and the low side pressure was low roughly low side - 24, high side was low too. I added 1 can of freon, with the AC on max. Static pressure without opening the knobs, and the engine running after recharge is: low side - 35, high side - 185.
I do have a question though. I know you don't open the high side while charging, but do you open either or both low and high side knobs knobs while testing?

 

[photog3740]

I just went for a test drive. It's still doing the same thing. Cold when I start driving, then after a few minutes, gets warm, then hot. So, I'm at a loss as to what it is.

 

[Tanners]

It sounds like your heater control valve could be stuck or the vacume line could have come off. That what happened to my 98 EB with the 4.0 SOHC.

 

[photog3740]

Where is the vacuum line located?

 

[Tanners]

The valve and the vac. line are on the pass. side by the frount of the engine. Its best to remove the frt. tire to get to the valve if you change it.

 

[fixt]

Hi there,
Thanks for responding. I do have gauges, Yellowjacket brand.
I hooked them up and the low side pressure was low roughly low side - 24, high side was low too. I added 1 can of freon, with the AC on max. Static pressure without opening the knobs, and the engine running after recharge is: low side - 35, high side - 185.
I do have a question though. I know you don't open the high side while charging, but do you open either or both low and high side knobs knobs while testing?

I don't believe you need to open valves to read pressures, just to add or evacuate the system.
That static pressure sounds low, it sounds like the compressor was running.
Static pressure will be roughly the same on both high and low after equilibrium is reached withe system off. Probably somewhere around 100 or so, its temperature dependent. It takes a little bit to equalize after the system is shutdown.

What does the low side pressure do with the compressor running and what is the pressure where the compressor trips. With AC on max and compressor running, does it draw down pressure and trip then restart after pressure comes back up, or does it just stay shut down?
What I'm asking is does the compressor cycle on pressure, off then back on?
If so, what are those pressures?

Check these with the window down, AC on max, blower on high. RPM should be about 1100 I think. You may need to enlist your SO to help with that part. Check the evaporator coils are unrestricted by debris or "stuff".

I ain't no expert by no means, but maybe an expert will jump in here after a bit to help.

 

[photog3740]

Here is the latest.
With the engine, cold and off, the static pressure is: low side - 87, high side - 85.
Start the engine, AC on max, low side - 32, high side - 165.
Rev the engine to about 1100rpm, low side - 82, high side - 85.
The AC clutch only went on when the car was first started. It never cycled after that.
So, with this in mind, the AC clutch is bad?

 

[fixt]

The static pressures are hard to tell anything about as they are temperature dependent, basically there's enough R134a in there to allow the compressor to start. After start when pressure is drawn down it might trip, but should restart if pressure increases enough, and it seems like it is. Since it doen't appear to cycle after the pressure increases, I personally am inclined to think the problem lies elsewhere.

As far as the clutch goes, there's a good picture of the assembly post 25 and 26 of the thread below, and the thread also talks a little about the EATC circuit which I don't have, just the manual controls with knobs.
http://www.explorerforum.com/forums/showthread.php?t=385863
Some troubleshooting ideas in there too, might help narrow it down.

Since the AC field coil and clutch engages one time at start, I would think that its working and something else is causing the trip. The running AC pressures at start are not out of line, though maybe a little low. The 1100 rpm pressures is after a compressor trip; the clutch is disengaged.
That ain't much help, but with a seemingly lot of people having trouble with their EATC controls, I might start investigating that if I were so equipped

 

[pitbulldell]

I had the same problem before with my a/c . it would work when you first started the truck but then stop working. Turned out to be the a/c clutch. Try this test next time it stops working turn the a/c on max and take the handle part of a large screw driver or a hammer and give the a/c clutch a few taps. Mine would then engage after a tap but would not engage on its on.

 

[TCPRR]

Ac

If you are low on refrigerant you have a leak.
AC systems are sealed and just don't need recharging for no reason.
Your system just needs refrigerant is the biggest lie in the world.
Sounds like you have air or moisture in your system.
The system needs to be serviced; evacuated, leak checked, repaired and recharged.