Hey guys I am in the middle of replacing the entire AC system on my truck and just have a few questions. I purchased a four seasons 38639 orifice tube per recommendation of @SkySkiJason and I cannot seem to get it to seat all the way inside of the evaporator tube. I made sure to put pag oil on the o-rings and I can only get it to go in the evaporator tube to where the end of the orfice sits about a 1/8 inch inside the evaporator tube. It is supposed to go in about another inch inside the EVAP tube but I have tried several times and ended up bending the orifice tube so I was wondering if it absolutely has to go all the way in? Seems like both of the o-rings on the orifice tube would be seated but just not all the way inside the evap tube like it is supposed to be. Have any of you guys had this problem seating the orifice tube? I measured my old orifice tube and the new one and both of them are 10 mm wide so I'm a little worried that maybe the new evaporator tube might be too small. Also wanted to ask if it might be a bad idea to use the four seasons 38639 orfice tube ( I believe it is smaller than the stock OT) being that I'm replacing all of the components on the AC system? I've heard this smaller orifice tube can cause things to freeze up on max setting so thinking I may need to use the stock orifice tube. Another question is after I pull a good vacuum and when I am charging the system with refrigerant should I hold the can upright or upside down? I've seen people do it both ways on the internet but apparently if you hold the can upside down it will let the liquid go into the system instead of the gas. Last but not least I believe that the entire system is supposed to take 9 oz of pag oil but my new motorcraft compressor comes with 7 oz already in it and from what I understand I'm supposed to put 1 to 2 oz in each component I replace such as the dryer, evaporator, condenser ,and new AC hoses. This would put me well over the 9 oz capacity so should I drain some of the PAG oil out of the compressor to allow for adding the extra oil in each component? Sorry for all the questions this is my first time working on a AC system so just trying to get it done right the first time. Thanks for any help.

 

Here is some pics of old EVAP and orfice tube. I don't even know how the AC system was functioning at all 😳.


Orifice tube was caked! I have no idea how woodchips got inside the AC system....

 

It has to go all the way in. Have you got it facing the right way?

 

Yes I made sure the arrow was pointing in. You can see in the picture I bent the orifice tube by trying to force it in.

 

First thing that comes to mind on the oriface tube is there is something left behind in the pipe, or the cage on the orifiace tube needs to be trimmed down a little to be able to fit inside.
If you're replaceing EVERYTHING, I wouldn't be afraid of adding a couple extra ounces just to coat the insides of everything. But no more. It will just reduce the performance of the AC. 9oz doesn't sound like much, but there's not a lot of room inside the AC system and it needs all the room you can give it.

 

The EVAP is a brand new motorcraft so there shouldn't be anything in there but I will double check. Unfortunately the o-rings are the widest part of the orifice tube so there's no way to trim it down. Thinking I may have got a EVAP tube that was manufactured incorrectly but I'm going to try a different orifice tube and see what happens. If there is 7 oz already in the compressor that only leaves me 2 oz for all the other components which doesn't seem like enough so that's why I was thinking about taking some out of the new compressor but I am a little unsure. Definitely don't want to hinder the performance of the system, once the oil is in there I would imagine it would be difficult to get it back out.

 

Looking up AC compressor mounting bolts in the tech section it says 50 ft lb. That seems like a lot of torque for a 10 mm bolt. Set my torque wrench to 50 foot pounds and I can't seem to get there, I feel like I'm going to snap the bolts. Does that seem right to you guys?
On edit: I did clean out the bolt holes with brake cleaner and compressed air, also cleaned The bolt threads and put a small amount of hilco lube on them

 

@Kwikkordead which part of the orifice tube were you talking about trimming? Not sure I see anything that I could actually trim but open to suggestions

 

If the compressor bolts feel tight then they're tight I wouldn't worry about a torque spec so much on something like that. Try your new orifice in the old evaporator just for a comparison. Might tell you if you're chasing the right tail or not. If it doesn't fit there then you may be right that you've got an oddball. If it does fit just fine then I'll be checking for an obstruction in the evaporator or possibly it got dinged and won't allow the new tube to seat properly.

 

I was just talking to my dad and he mentioned the same thing. The new orifice tube slipped right into the old evaporator. That's a real bummer, looks like I may have to remove the evaporator again to trade it in. I will be sure to check for any obstructions before I do so , here is a pic of the new orifice tube inside of the old evaporator 😩

 

Rather than change the evaporator coil again, maybe you could score the orifice that goes with it.

 

The EVAP doesn't come with a orfice tube, is that what you were referring to?

 

Yeah, is it possible that there is a mismatch rather than a defect? If that's the case, maybe you could find the orifice that goes with the evap coil.

 

I just put my borescope inside the EVAP tube and it is clean as a whistle. I then tried to put the old orifice tube inside the new EVAP and it does the same thing, doesn't go all the way in. The whole reason I spend extra money on motorcraft parts is to avoid situations like this. I guess if it wasn't for bad luck I wouldn't have any luck at all....

 

Hey, that's my song.