Hi,

Been working through an AC problem on my 2002 7.3 Excursion XLT; the high side gets to 350-450 with only 2-2.5 cans. Up to now, I have replaced pretty much everything except the cabin evaporators and hoses. The system now evacuates ok. My current operation is to replace the front evaporator and now have it out. Man those 11 screws that hold the housing are a pain to remove. But it is out and I have confirmed that w/o the orifice I can blow air through the unit without too much difficulty. Adding in the orifice (new) adds significant difficulty using my breath but I have no experience here. I am assuming the front probably wasn't the issue. The rear suction quick disconnect appears to be frozen solid; been spraying PB a lot and have gotten a lot of the crud I saw on the spring loose but I cannot even turn the pipe. The high side (smaller) came off ok. Is this normal to expect difficulty on these pipes? Inside the rear well, I was able to take both the nuts off on the right side of the expansion valve but I cannot budge the evaporator side. I am not too concerned about that as I can hack saw those off once I figure out how to remove the panel. Are the evaporator nuts typically on crazy hard? As of now, my only concern is the suction side quick disconnect. Destroying that link would not be my first choice as I would have to both replace the long runner as well as possibly the pipe going up into the chassis to the expansion valve. Any ideas on any one? Any ideas on how to get the spring out? Although since the pipe doesn't twist around I am more concerned about that. I believe there is a rear filter unit just above that quick disconnect that may be clogged which could explain the high readings. Assuming the back is the culprit would that explain the 350-450 high side reading with only 2.5 cans installed? I decided to cease filling at that point. Thank you for any advice or pointers.

Best,
Chris

 

I'm not familiar w/ the EX's but to be honest I'm having a little trouble understanding all the components you're referencing, in particular the connections that are giving you grief. The saying goes "A picture is worth a thousand words". It may help us work through your problems.

 

Lack of airflow thru the condenser causes the high side to have high pressure
A plugged orifice also causes it
You have torn into it so much, it is going to be hard to give you advice
You make sure the fan by chance is not going the wrong way and check the condenser fins for debris
Check the fixed orifice
Leave the evaporator alone

 

UPDATE : Thanks for the advice. 2 things that I want to document because they informed me for future work. The first is that my new set of AC manifold gauges had a leak on the high side. Not sure how much this impacted the result but I replaced that and my vacuum is better held now. The other is that I took advice to use the garden hose to spray the condenser while filling 134a and it made all the difference. My high side pressure stayed around 120-160 psi during the procedure while I frequently sprayed it. It makes me remember and respect the equation PV=nRT. Has anyone considered adding AC fans to the condenser? I assume they didn't come standard as my truck didn't have them. Not sure how much they would help but I guess the unit, as-is, would cut out during idle as I imagine the pressure (ie temp) would get too high with little airflow under those conditions.

Best,
Chris