R 134 A conversion
- Thread starter Wubbasnake
- Start date
Doing the R134a conversion on my 90 LX 5.0. Can someone tell me where the orifice tube is located and if it is servicable? Thanks.
Nobody will be able to tell you if your specific tube is servicable or not.
If you're getting that from the directions, they are asking you to find the orifice tube, and then examine it to determine whether or not it needs replacement.
The orifice tube is in the liquid line which runs from the condenser to the firewall and attaches to the evaporator.
If you're getting that from the directions, they are asking you to find the orifice tube, and then examine it to determine whether or not it needs replacement.
The orifice tube is in the liquid line which runs from the condenser to the firewall and attaches to the evaporator.
PuterAmI
Member
I would not try to service the orifice. As sgarlic mentions, it is in the liquid line. Just buy new since you are converting anyway. The orifice is the first place that the system will become clogged. It's only ~$25 for a new Ford one.
There is some question about the exact location of the orfice tube.
If it was in the liquid line that runs from the condensor to the evaporator, the liquid line would get cold because of the expansion of the liquid to a cold gas. This would expose the tube containing the cold gas to engine compartment heat, thus reducing the efficency of the air conditioning.
My Chilton's manual shows it in the inlet of the evaporator, which is where I would expect it to be located.
If anyone has actully removed & replaced the orfice, please post and clairfy the situation.
If it was in the liquid line that runs from the condensor to the evaporator, the liquid line would get cold because of the expansion of the liquid to a cold gas. This would expose the tube containing the cold gas to engine compartment heat, thus reducing the efficency of the air conditioning.
My Chilton's manual shows it in the inlet of the evaporator, which is where I would expect it to be located.
If anyone has actully removed & replaced the orfice, please post and clairfy the situation.
I would buy a new liquid line as (PuterAmI) said. It's quicker to do. About $25 from a autoparts store. You won't be happy with 134a. I have experience. I have tried 134a, Freeze12. I decided R12 IS the best cooling. If you have no air, you HAVE a leak. Better find it before putting money on a recharge. Find a GOOD repair shop do a leak test.
PuterAmI
Member
*raises my hand*jrichker said:
Only a few hundred times.
It is in the liquid line on the Fox. Follow it from the condenser. See that bump halfway? In there is the orifice. Trying to "service" the orifice is more expensive than just replacing the line. It is a "fixed" orifice.
For a brief explanation of the parts and flow of the A/C, please see the section titled "Introduction to the A/C system" in the below URL.
http://www.veryuseful.com/mustang/tech/general/R12-to-R134A-Conversion.html
I have a different experience. My orifice in my 89 was right at the intake to the evaporator. It was in the same place as my buddies 91. Both of them were not fixed, and were replace with a 2 dollar replacement from autozone
I use 134a in both my 89 and my 65. just make sure you replace the dryer. When its 105 out here at idle in the 89 I see about 53 degree temps. 52 degree drop seems like plenty to me.
The 65 doesnt have quite as effiecients a system(it is still stock components) but at idle i see about 61-65 degrees out the vents. Still very very livable.
edit: my apologies I read the post wrong
I use 134a in both my 89 and my 65. just make sure you replace the dryer. When its 105 out here at idle in the 89 I see about 53 degree temps. 52 degree drop seems like plenty to me.
The 65 doesnt have quite as effiecients a system(it is still stock components) but at idle i see about 61-65 degrees out the vents. Still very very livable.
edit: my apologies I read the post wrong
PuterAmI
Member
Strange, in all that I have done, I have never seen it in another place. Perhaps it is the plant it was installed at, not the year.
jrichker, your link does not work. There is no DNS entry for jrichker.stangnet.com, therefore I cannot change it to an IPv4 address.
jrichker, your link does not work. There is no DNS entry for jrichker.stangnet.com, therefore I cannot change it to an IPv4 address.
You are right. It must have disapppeared in one of the recient server crashes. Thanks for the heads up.PuterAmI said:
See http://bellsouthpwp.net/l/r/lrichker/ for my mirror site.
Zero_chance
Founding Member
Im not sure myself having only my own AC deleted car to reference from so I asked a "Master" mechanic and his response was "I thought them old Mustangs used a TXV" (Thermostatic Expansion Valve)
Soooo... no help there.
Soooo... no help there.
PuterAmI
Member
Definitely not. GM mostly used those. If you look under the hood of any late 60's, 70's muscle car (I had a bunch) you will see that thin metal line that is a dead giveaway to the TXV.Zero_chance said:
There are basically two systems in the American mobiles... the orifice/accumulator, and the TXV/dryer. The TXV/dryer is the one that has the sight glass up near the condenser. Remember those?
Zero_chance
Founding Member
Yeah, I know, I was just trying to point out how much this particular "mechanic" didnt know. He thinks hes Gods gift to the automotive world and hes really not. Theyre actively trying to replace him. Ive seen a lot of TXV cars and the sight glass. They cant use them on R134A because the polyalkylene glycol oil they use with R134A doesnt mix as good as the mineral oil did with R12 so it constantly looks like theres air moving in the system. If they still had sight glasses Im sure people would be trying to charge already filled systems. TXV systems are supposedly more efficient though I cant say Ive ever really compared the two. If it comes out cold and stays that way its efficient enough for me.
I've done a total of seven R-12 to R134a Mustang conversions (one 87, two 88's, two 89's, one 90, and one 92) and I've never seen the O-tube in any location other than the liquid line as previously mentioned. I also agree about changing the whole liquid line instead of trying to remove the old O-tube. Just remember there are different orifice tubes with different size openings/restrictions, and the color of the orifice can differentiate their diameter. I usually use the Ford Motorcraft Blue O-tube when converting systems over to R134a.
PuterAmI
Member
Camman, could that have been a filter that you saw on your cars? Even according to this article that I read a long time ago, the orifice is always located between the condenser and the evaporator. It makes no sense to meter the flow of the hot compressed gas. The orifice meters liquid.
ORIFICE TUBE
The orifice tube, probably the most commonly used, can be found in most GM and Ford models. It is located in the inlet tube of the evaporator, or in the liquid line, somewhere between the outlet of the condenser and the inlet of the evaporator. This point can be found in a properly functioning system by locating the area between the outlet of the condenser and the inlet of the evaporator that suddenly makes the change from hot to cold. You should then see small dimples placed in the line that keep the orifice tube from moving. Most of the orifice tubes in use today measure approximately three inches in length and consist of a small brass tube, surrounded by plastic, and covered with a filter screen at each end. It is not uncommon for these tubes to become clogged with small debris. While inexpensive, usually between three to five dollars, the labor to replace one involves recovering the refrigerant, opening the system up, replacing the orifice tube, evacuating and then recharging. With this in mind, it might make sense to install a larger pre filter in front of the orifice tube to minimize the risk of of this problem reoccurring. Some Ford models have a permanently affixed orifice tube in the liquid line. These can be cut out and replaced with a combination filter/orifice assembly.
Reference - http://www.familycar.com/Classroom/ac1.htm
ORIFICE TUBE
The orifice tube, probably the most commonly used, can be found in most GM and Ford models. It is located in the inlet tube of the evaporator, or in the liquid line, somewhere between the outlet of the condenser and the inlet of the evaporator. This point can be found in a properly functioning system by locating the area between the outlet of the condenser and the inlet of the evaporator that suddenly makes the change from hot to cold. You should then see small dimples placed in the line that keep the orifice tube from moving. Most of the orifice tubes in use today measure approximately three inches in length and consist of a small brass tube, surrounded by plastic, and covered with a filter screen at each end. It is not uncommon for these tubes to become clogged with small debris. While inexpensive, usually between three to five dollars, the labor to replace one involves recovering the refrigerant, opening the system up, replacing the orifice tube, evacuating and then recharging. With this in mind, it might make sense to install a larger pre filter in front of the orifice tube to minimize the risk of of this problem reoccurring. Some Ford models have a permanently affixed orifice tube in the liquid line. These can be cut out and replaced with a combination filter/orifice assembly.
Reference - http://www.familycar.com/Classroom/ac1.htm
LXSTASY
Founding Member
I bought the conversion kit and did it in my 91. The nipple that I put the conversion coolant in was in the front. I haven't had a problem with the system leaking and it still works after sitting the winter. I think I paid ~$40 for the kit and it worked well.
rd
Founding Member
I have not worked on the 89 ac much yet, but my 82 Bronco had the orifice tube in the inlet to the evaporator, just outside the firewall. It was easily replaceable.
In the 89 and similar Foxes, is it in a fitting in the liquid line out in the engine area or just before the firewall? Is it not easy to pull and replace?
If they are stubborn, can't you just screw something into them and pull them out?
In the 89 and similar Foxes, is it in a fitting in the liquid line out in the engine area or just before the firewall? Is it not easy to pull and replace?
If they are stubborn, can't you just screw something into them and pull them out?
PuterAmI
Member
It is in the liquid line. The liquid line runs from the condenser to the evaporator. This is in the engine area before the firewall.rd said:
No, you cannot. A "liquid line with orifice" costs less than $25. If you want to try and just replace the orifice in the liquid line, you need a crimping tool that goes for ~$350.
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