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Excursion A/C issues

Crude dude on Sun August 05, 2012 12:06 AM User is offline

Year: 2000
Make: Ford
Model: Excursion
Engine Size: 7.3
Refrigerant Type: r134a
Ambient Temp: 100F
Pressure Low: 50
Pressure High: 225
Country of Origin: United States

Hello guys, Ive been a frequent reader of but am a new member to the forum and I have a question to ask. I recently replaced the compressor, condenser, orifice tube, rear expansion valve and drier on my Excursion. I did not use any chemicals while flushing the lines and evaporators, I just used a lot of time and air until nothing else came out. I added the 14oz of oil to the system in a couple of different components and then vacuumed the system. I am not sure if my vacuum pump is weak or maybe my gauges are incorrect but all I could pull was 26". I pulled vacuum for 40 minutes and the system held vacuum for a couple of hours with no change in the needle. I installed the 68oz of 134 (5.5 cans of DuPont brand without dye or oil), slowly into the system and it will not cool below 65-75 degrees from the vents. Pressures are steady as a rock at 50/225 while idling and engine warmed up, rear a/c on as well. I recently replaced the heater hose vacuum switch with a ball valve and it did not help at all. System is quiet also, anyone have any suggestions? Evaporator lines in and out are cold as well as the lines going to the rear evaporator, I have an infrared temp gun but for some reason it says that those "cold" lines are 75-80 degrees although they feel much colder than that.

Dougflas on Sun August 05, 2012 2:15 AM User is offline

IR temp guns when used on alum lines can give false readings. IR guns do not like shinny metal. If the temps of the lines going into and out of the evap are the same, that will tell you the evap is filled with refrigerant and that is good. To evaluate your system, you need to give us the temps amd pressures at 1500 rpm. You should zero out your guages before you start. It is possible that you may have hard a deeper vacuum that 26". If your guages were zeroed, then 26" is not enough depending upon the sea level you're located.

Crude dude on Sun August 05, 2012 2:05 PM User is offline

Thank you Dougflas. I will try to work on it today and report back.

iceman2555 on Sun August 05, 2012 2:53 PM User is offlineView users profile

There is a good possibility that the system still has a significant amount of lubricant left from the OE charge. Blowing air thru a system may not remove all lubricants. Also, the system appears to be undercharged. Adding refrigerant by cans is not an effective method to recharge a vehicle. Consider that there was not a mention of refrigerant charge necessary to precharge your AC manifold hose assembly, this alone could account for 2-4 oz of refrigerant. Also consider that it is very rare that all of the refrigerant is removed from cans this could also contribute to a possible undercharge. Try a open door, max cool, high blower, engine at idle (N.O.T). Allow the system to operate with both system for about 5-7 minutes. Test the inlet and outlet temps of the evap, may have to rely on the finger test...since Infrared/Laser are almost useless when operating in a high heat area such as the engine compartment. Temps should be very close to each other. If the outlet is warmer than the inlet, test the inlet and outlet temps of the condenser. Feel the discharge line (compressor to condenser), if this line is extremely hot and the liquid line (condenser to evap) is warm, there is a very good possibility that the condenser is restricted. This will reduce the amount of refrigerant entering the evap and reduce system cooling. May use the temp gun for this test since this is away from excessive engine heat. Temp should be below 30 degrees F. An excessive temp drop would typically indicate a restricted condenser. Suggest this test even though the condenser has been replaced. We have experienced several failures associate with new condenser that were restricted with flux or other contaminants.
If the outlet is warmer (more than 8 degrees) add a couple oz of refrigerant (guess at the weight) and allow to re stabilize and re test temps. Do this till the temps are almost the same. From your post, it appears the system is undercharged.
We recently tested several different 'heat guns' and were surprised to learn that some were as much as 70-90 degress out of spec. Underhood temps play havoc with these units. A simple temperature tester with thermo couplers works best for AC work.
Good luck !!!

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

Crude dude on Sun August 05, 2012 3:53 PM User is offline

The wife has the Excursion at the grocery store for a while so I wont be able to check the temps for a while. I do know that the inlet and outlet of the front evaporator feel the same and they are chilly but I do not know what the temps are. The rear evaporator after the expansion block, if I remember correctly, was the same temps in and out also. What is your opinion on the 6mm tube condenser vs the tube and fin style condensers? I had the option of either but I opted for the tube and fin (factory was 6mm tube), I hear they are more efficient?? I am going into the blazing hot garage for a while to see if my manifold gauges are zero'ed out.

Edited: Sun August 05, 2012 at 3:59 PM by Crude dude

iceman2555 on Sun August 05, 2012 6:03 PM User is offlineView users profile

There are two type condenser being used with 134a. The 6mm pic and the Parallel Flow High Efficiency units. The 'Tube and Fin' type condenser was utilized with R12 and lacked the condensing efficiency to work with 134a. Please post a photo of your condenser to determine if you have the correct unit. It is doubtful that your's is actually a 'Tube and Fin' unit, but post the photo.
The inlet and outlet of the rear unit should not be the same temp. If the rear is a TXV (expansion valve) the inlet line should be warm and the outlet should be cold. If it is an orifice tube system, my catalogue states it is a TXV, the inlet and outlet would be the same.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

Crude dude on Sun August 05, 2012 7:23 PM User is offline

Sorry, that's what I meant was a parallel flow condenser. I was side tracked for a bit because I'm helping a friend try to gather parts for his 87 Bronco convert to 134. There are 4 lines going into the back TXV so I will check which ones are cold or hot.

bohica2xo on Sun August 05, 2012 8:50 PM User is offline

Idle testing is only part of the picture.

Windows down, cabin fan on highest speed. Engine speed to 1500 rpm. Hold 1500 rpm for 3 minutes to stabilize system. Record center vent temp, high & low side pressures while still @ 1500 rpm after 3 minutes.

Non-contact temperature measurements are known for errors. Use a regular dial type thermometer in the center vent. Leave it in the vent for the duration of the test.


"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Crude dude on Thu August 09, 2012 1:37 AM User is offline

Well I finally had some time to tinker with the ac and something told me to evacuate the system and check the orifice tube. I pulled the orifice tube and it was 2/3 covered in metal trash. Now I'm really in a situation because this is what happened to the last system before I replaced it a few weeks ago. I'm not sure if there was something left in the lines because I cleaned everything (except the evaporators) pretty good. Now I have to replace everything and start over, clean my gauges and manifold and check my recovery unit. Is it just me or is ac work a vicious never ending cycle haha.
Im pretty sure I still have warranty on the compressor, if it failed. I also picked up a self adjusting orifice tube for 105F and hotter weather, should I use this on the next build???

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