'03 A/C Evaporator clogged...i think

[joners]

2003 Explorer with rear controls. I've searched and couldnt find much pertaining to my problem.

A/C wasnt working a couple months ago, clutch wouldnt kick in. Took to shop and they said it appears to have no leaks, they evacuated the system and refilled it. At the time of refilling it, I was sorta helping them out and the rear controls were left off. A few days ago I took the truck back to the shop as the A/C wasnt that cold out of the vents, I told them that it has rear controls and that they were off when they filled the system. He topped it up and said it appears to have no leaks. So today while on a 9 hour road trip, about 3-4 hours in I notice that there is barely any air coming from the vents. It's cold but there is just no power. I turned off the A/C and just let it blow air, after a few minutes the vents have much more power. I am assuming the evaporator is icing up.

Now, has anyone ever taken the blower assembly apart? Is it easy to clean the evaporator, if all mine needs is a cleaning?? (I hope)

I also noticed that the compressor doesnt cycle on/off, it runs constantly. When I got the A/C recharged the first time, it was cyling on/off.

Im out of town for the new few days so I wont be able to take it to the shop. Do I just have a bad switch perhaps, and the evaporator isnt clogged?

 

[rhauf]

2003 Explorer with rear controls. I've searched and couldnt find much pertaining to my problem.

A/C wasnt working a couple months ago, clutch wouldnt kick in. Took to shop and they said it appears to have no leaks, they evacuated the system and refilled it. At the time of refilling it, I was sorta helping them out and the rear controls were left off. A few days ago I took the truck back to the shop as the A/C wasnt that cold out of the vents, I told them that it has rear controls and that they were off when they filled the system. He topped it up and said it appears to have no leaks. So today while on a 9 hour road trip, about 3-4 hours in I notice that there is barely any air coming from the vents. It's cold but there is just no power. I turned off the A/C and just let it blow air, after a few minutes the vents have much more power. I am assuming the evaporator is icing up.

Now, has anyone ever taken the blower assembly apart? Is it easy to clean the evaporator, if all mine needs is a cleaning?? (I hope)

I also noticed that the compressor doesnt cycle on/off, it runs constantly. When I got the A/C recharged the first time, it was cyling on/off.

Im out of town for the new few days so I wont be able to take it to the shop. Do I just have a bad switch perhaps, and the evaporator isnt clogged?

Normal compressor operation is usually constantly running at idle, and cycling on and off at higher RPM's.

if you're evaporator is icing up, i'd try replacing the expansion valve. other than that, it could possibly be that the filter is clogged (the filter is usually located on the output line from the compressor, built into the hose)

if you have front, AND rear a/c, and they both stop working. i would say it's very unlikely that both expansion valves are bad. and i would therefore blame the in-line filter. if only one system quits working, then it's the expansion valve for that system.

oh, if the filter is clogged, the accumulator will be warm (while the a/c is running, after the vents go warm) if it's icing up, the accumulator will be really cold (its temperature rides with the evap)

you could also feel the accumulator, if one half is warm, and the other is cold, the accumulator is to blame.

 

[joners]

The vents dont go warm, there is just no airflow after the A/C has been on. Hopefully today is warm enough to need A/C. I'll time how long it takes to have poor airflow.

 

[jrford]

could the A/C drain be plugged allowing it to ice up? I haven't tried this on the Ex. but on another truck it was easy to drop the fan motor, 3 screws and wiggle it out. then with a mirror you can get to see inside a little bit. Also you might find junk it that fan blade which can kill air flow.
Other than that maybe a Blend Door issue as a wild guess.

 

[joners]

Rear air flow doesnt appear to have affected air flow when front vents are hardly blowing any air.

 

[joners]

Well today it didnt seem to have poor airflow like yesterday.

There is water on the ground after sitting idle, so it's draining off the evaporator. The accumulator is cold, it looks like there is slight ice on the fittings where the insulation stops.

I talked to the A/C shop and they said its most likely dust/dirt blocking airflow. This weekend I'll try to take the heater box apart and see what I find in there.

 

[rhauf]

Well today it didnt seem to have poor airflow like yesterday.

There is water on the ground after sitting idle, so it's draining off the evaporator. The accumulator is cold, it looks like there is slight ice on the fittings where the insulation stops.

I talked to the A/C shop and they said its most likely dust/dirt blocking airflow. This weekend I'll try to take the heater box apart and see what I find in there.

if there is ICE on anything, i'd say you have a problem. it's getting too cold. you probably need to change the expansion valve.

and now that i see you mean the air flow actually stops, i agree with your original idea that it's icing up. replace that expansion valve before something gets damaged (it can ruin the evaporator if it ices up)

 

[joners]

may be a dumb question, but can the expansion valve be changed with out having to empty out the refrigerant and fill it up again?

 

[rhauf]

may be a dumb question, but can the expansion valve be changed with out having to empty out the refrigerant and fill it up again?

Nope, sorry.

 

[joners]

Seems the compressor doesnt shut off. It used to cycle on/off when idling, and when RPM's would raise.

Would this be associated with the expansion valve or something else? I guess thats why it's icing up? I took a look at the heater box today. Looks like the evaporator is located behind the dash where the HVAC controls are....

 

[joners]

So it ended up being a pressure sensor. The shop took it off, cleaned it up a little and is working properly now. He said if it keeps doing it, just buy a new sensor.