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This is my wifes vehicle and I feel awful that her and the kids have to ride around in this oven. She loves the truck so I am up against the wall trying to fix the air for them. I have replaced the compressor, condenser (now a parallel flow), both evaporators, accumulator, both metering devices. Pulled a vacuum for two hours and vacuum held for several hours after. Pressure tested and it held for several hours at 300 psi. 14 ounces of PAG 46, 68 ounces of 134a and poor vent temps. Something that I cant wrap my mind around is for example, driving this truck a couple days ago (In Phoenix) it was 108F, drove several miles down the freeway and vent temps were mid 60s, definitely better than 108 but not great. Go into our destination, truck parked in the direct sun for a few hours. When we left the ambient temps were still around 100F but now that the sun is going down the vent temps are about 45F. Still hot out but it seems this truck doesnt like the sunlight. It could be 108F outside at night and the AC would be very cold, 108F with sun up and vent temps are mid 60s.

Windows are tinted, plenty of airflow through vents, both evaporator boxes are sealed up with tar tape. I cant get the low side numbers down to a normal level, they are hovering around 48-55 psi while high side is in the correct area of 250 psi. I have even installed a smaller orifice tube than what factory uses and all it does is cause the high side to go up, low side doesnt go down. I do a good share of AC work and have diagnosed a lot of issues on other vehicles but this one has me stumped and I think it is all because the rear system uses a expansion block which is variable orifice size.

I should also note that these numbers are while running both front and rear systems on high with windows down and engine idling ( I didnt have anyone to run the throttle while testing). Anyone else have this issue and find a cure? Thanks fellas and sorry for the long read.
 

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You've covered a lot of the bases. I would check that your blend door is closing completely and check to see if you have a heater control valve. If not, might consider getting one.

Also, might want to put eyes on the evaporator. They can get pretty nasty sometimes.


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Unfortunately I have covered those bases as well. Both evap's are new and I also installed ball valves on the three heater hoses going to and from the heater cores. The third valve was so hot coolant wouldn't find its way backwards into the heater core. I am stumped. The last time I worked on the AC on this truck was 2 years ago and I don't recall if I checked the recirculate door, I'll try looking into that too.
 

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2003 Excursion with the same problem

I've done every thing you mention in your AC repair and I have the same problem, I live down in Yuma, AZ with temperatures in the 115 area and the best vent temp is 65 F I'm at my wits end. So what have you found any thing? Any help would be appreciated
Bill
 

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I haven't figured it out at all. I drove the truck all last week and if I stayed on the freeway and was moving 50 mph or more for several miles it would actually get to be decent air temps, not great by any means but maybe mid 50s. I am in Phoenix and was seeing same ambient temps as you were.
On another note, after say 5pm the air becomes brisk from the vents and after 7/8 pm the air temps are mid 40s from the vents so I'm guessing the evaporator on this truck just isn't efficient enough to cool an apartment size vehicle. My next step is to install an electric pusher fan and see how it does.
 

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It might be that the condenser isn't getting enough heat removed to liquefy the refrigerant. Considering the difficulty in liquefying R134a in the first place, the huge stack of heat generators up front, the dry ambient heat you have- that might be the issue. A sight glass sure would be nice


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I haven't figured it out at all. I drove the truck all last week and if I stayed on the freeway and was moving 50 mph or more for several miles it would actually get to be decent air temps, not great by any means but maybe mid 50s. I am in Phoenix and was seeing same ambient temps as you were.
On another note, after say 5pm the air becomes brisk from the vents and after 7/8 pm the air temps are mid 40s from the vents so I'm guessing the evaporator on this truck just isn't efficient enough to cool an apartment size vehicle. My next step is to install an electric pusher fan and see how it does.
That was my next step too, I placed my shop swamp cooler in front of the Excursion with just the fan on high no water and it dropped the low side around 10 psi and the vent temp also came down to around 58 degrees, so I think adding a fan out front mounted to the condenser would help out at low speeds and maintain temperature from the vents. I was also thinking maybe it's time to replace the clutch fan and or replace the main fan with two 15 or 16 inch electric fans, my Excursion has 222K on it maybe it's passed due for a change.
 

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A little update for you, I installed a Flex-a-lite 272 Super Duty Fan and a Flex-a-lite 32050 Temperature Sensor this made a big change in vent temps during stop and go traffic in Yuma, AZ. During long drives I can the vent temps down in the mid 50's to the high 40's this is best I can do, like you said it's trying to cool down a small size apartment. PS With in about 5 miles of highway driving it's feeling pretty good inside compared to the over 100 degrees outside. Last but not least the MPG jumped up to 18 to 19, Hope this helps
 
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