Well, I've tried everything I can think of, searched the forums and I'm still wondering what to do next to fix my AC. 2002 Excursion 7.3L

My AC blows air between 70 and 80 degrees (as measured by my a meat thermometer). Outside air is right at 98 degrees. I checked my compressor discharge line (warm) and my inlet pipe is cold and sweaty. I bought a can of refrigerant (R-134a) with a dispenser and gauge (the gauge is one of the color coded ones--4 color codes & corresponding pressures: green(0-25)--add, blue(25-45)--filled, yellow(45-65)--see an AC tech, and red(65-200)--see an AC tech). My pressure is right at the top of the blue band (45), so I did not add any refrigerant.

I cleaned the condenser fins and made sure the evaporator drain tube was clear. Still no joy.

When it is below 95 degrees outside, the AC will cool well enough going down the highway, but above that and it struggles, particularly while idling. I wouldn't mind doing one of the mods mentioned in the forum, but I think I need to get the system right before I start any mods. I figure it ought to put out air around 60 degrees, even with it really hot outside.

One thing that rubs me the wrong way is the outside temperature indication...it takes several minutes to indicate an accurate temperature, and only after driving for several minutes (my understanding is that this is the way it is supposed to work).

Any suggestions?

 

You need to rebuild your compressor clutch. If your guage is reading correct psi for r-134a then do not add any more. check the air gap btween the outside of the compressor clutch and the pulley, it should be between .025 and .028, any more(which means it is worn) and the compressor will not engage fully. any less, and the compressor will not disengage when cycled by the swith.

I just rebuilt the one on my wifes Expedition this week end and now its nice and cold in there.

 

Thanks for the reply. I checked the air gap and it was right at .028-.029, so it is right at the edge. I looked online for some parts and found a new clutch for about $50. Is this in line with your experience? How long does the job take?

 

I am sure you have read that you can remove the 8mm bolt holding the clutch to the pullley, and remove a washer(shim) from behind the clutch plate. this will bring the air gap closer, but dont go below .020.
the clutch kit for my wifes Expedition was $93. The hardest part of the R/R was to pull the pulley and the electro magnet off the pump. You need a 8MM socket for the bolt on the clutch plate, a pair of snap-ring pliers to remove the snap ring holding the pulley on, a 2 jaw puller to remove the pulley, and the magnet. make sure you seat the new magnet back all the way before you try to put the new pulley on other wise you will have clearance issues.(hint: a small rubber hammer does this well) Press pulley on shaft with either the hammer or unshimmed clutch plate by tightening the 8mm bolt to pull the pulley into place. replace snapring, shim clutch face, replace bolt. replace belt, start truck and turn on A/C to max to verify that clutch is engaging and running.
I would say this is about a 1 hr job, 2hrs tops.

hope this helps.
the bad thing about my wifes expedition is the a/c compressor is mounted on the lower pax side of the engine so I had to do it from a creeper.

 

Have you confirmed your blend door isn't stuck?? You may just be getting heat from the heater core... Does your Ex have the vacuum valve to shut off the core when on Max? Do you notice a difference between Max & "normal" AC?? How about the rear AC?? What's it feel like??

 

If it cools better going down the road I would ck the fan clutch . when you touch the discharge line it should hot not warm. 45 psi not to bad for dual units got remember that alot space to cool.If the discharge line is warm then the head pressure is not to high I would add that can you have see if it makes a difference. but still ck the blend door I have pencils keep the door open good luck.

 

Thanks again for all the replies--I really appreciate it. It is awfully hot here in Alabama!

Let me preface my comments with this: the only source of info I have for my Excursion is the Haynes repair manual. That being said, I really don't know how to check to see if my blend door is stuck open and I couldn't find it in the manual.

I'll check my rear air today on the way back from work. Max Air (recirculate, I assume) does cool off the cabin faster, but not substantially so. I'll see if I can't check the difference with the thermometer today. In regards to the mod (or OE in some) that shuts off the coolant to the heater core--I read a lot about that one, but I'm not sure how to check for that either.

Any help on these items would be appreciated, too.

 

If your going to be near Montgomery or Prattville anytime soon I would be happy to help you. PM sent

 

bdrummonds,

Thanks for the generous offer--I usually head down towards Clanton once a week...it wouldn't be too hard to continue down to Montgomery. I got your PM and once I get a chance to catch up on everything, I'll give you a call.

 

Here's a guy who deserves some reputation points! Now, if only I knew how to give them...

Way to go bdrummonds! What a guy!