EverydayDiesel

For those of you that know, I have replaced the compressor, liquid line, condenser and drier all at the same time a few months ago. I pumped down the system with a 5fcm robinair pump and installed the proper amount of freon. The a/c worked for a few months until recently it got hotter and hotter.

My compressor was cycling on and off so I hooked up my gauges and added about 1/2 can of r134 to the system. The compressor stopped cycling so rapidly which was good but the a/c still blows hot. The gauges read 25/275 in 95 degree weather.

The condenser is getting hot. The liquid line that goes from the condenser to the firewall is hot towards the front of the truck and is ice cold (with condensation on the line) towards the firewall side. The other line coming from the firewall into the drier is normal (warm temp) the same as the actual drier itself.

What is happening? Is the box inside the truck plugged? Is this the symptoms of low refrigerant? What do I need to do to trouble shoot this further?
Thanks for the help


Here is whats going on

Diesel Doc

be sure the blend door isn't stuck. You may be a little low still low side should be around 40

EverydayDiesel

how do I do that? would the blend door cause the drier not to get cold?


and why would the high side be about right while the low side looks low according to the service manual?

ive learned alot about a/cs in the recent months but I still have alot to learn

jrs_dodge_diesel

The evaporator could be plugged with dirt. The incoming air is not filtered going through the airbox.

Diesel Doc

+ 1 on the evap being plugged you would have to take the dash apart to check if it is just blow it out

EverydayDiesel

anyone have a write up on taking the dash a part?
Do the air bags have to come out?

1-2-3

I just recently changed my evap. It had a leak. I don't know how any air ever passed tru it. The surface was almost completely covered with a dirty grime.

First question from me==> What prompted you to change the parts you did?

EverydayDiesel

my compressor clutch failed...
i decided to replace the drier because everyone said to replace it with a new compressor.

The liquid line was a little worn so I went ahead and replaced that and also the condenser up front was dented and in bad shape so I replaced that also

Diesel Doc

I should have thought of this earlier. did you check the orifice tube to bee sure it was clean when you changed all the parts. also did you add oil to the system. was the compessor already "loaded" when you got it a over oil situation can wreak havoc and make you pull your hair out also.

EverydayDiesel

the liquid line (which contains the orface tube) was brand new so I assume it wasnt plugged plus it worked for a few months with no problems.

I added 6.25 ounces to the compressor. I flushed out the evapcore with a/c cleaning chemicals and blew it out with compressed air the best I could. I bet this is where my problem is, its the only thing that makes sence at this point. I guess ill go to napa or orileys and pick up a new one and replace it. Pump down the system and add the refrigerant.

EverydayDiesel

One question for all you experts....

I added 6.25 ounces of pag oil when it was brand new...ran it for 2 months just fine.

Now that Im opening up the system, replacing the evap core and pumping down the system again. Do I have to add any more oil?

Diesel Doc

alot of compressors come with oil in them already thats why I asked if it was a loaded compressor if it was and you added oil you are over oiled.
If you could blow air thru the evap it is probably ok we were talking about the external fins being full of dirt I see it alot on trucks that work in the dust alot

EverydayDiesel

I drained the oil out of my compressor first....and I measured it...it was a little low so I added enough to make it read 6.25 and then I poured it back in the compressor.

1-2-3

"I flushed out the evapcore with a/c cleaning chemicals and blew it out with compressed air the best I could"

I can't help but ask how you did this? The dash has to be removed to get to it. Do you mean the condensor coil in front of the radiator?

May be bad news now, but you could have replaced the clutch without removing the compressor. You need a special puller, but most auto parts places will loan you one when you get the clutch.

Diesel Doc

I think he meant internaly with the lines off