Orifice Tube Install

[DavidProehl]

This should be super easy, for some reason it isn't.

I'm wrapping up my install of a new evaporator, and I'm installing the orifice tube (probably should have done this before the evaporator was in the car). I used 134a a/c oil to lube up the inside of the tube and the OT, but it was taking a serious amount of force to go in, and it didn't go in more than half way. Eventually, I broke the OT with the force I was applying before getting it all the way inserted.

Luckily, I happen to have another OT on hand, but I'd be interested in some pointers on getting it in there. I'm putting it in the smaller of the two pipes, and in the direction shown in the below photo.

http://i.imgur.com/3XCew.jpg

From reading this thread (http://dmctalk.org/showthread.php?1028-Where-is-the-Orifice-Tube&), it sounds like it should just slide in. What am I doing wrong?

[Bitsyncmaster]

I can't see your photo at work (office will not access the photo sites) but the OT should slide in without to much force. Make sure your tube on the evaporator is not bent where the OT installs into. The short side goes into the hose coupling so really as long as you can start the treads.....that will push it in the correct amount.

FYI:
OT tubes come in two types and many sizes. The type change is just where they put the finger to pull the tube with. One type goes into the hose and the other type into the metal tube. Many systems put the OT into the hose end at the output of the condensor.

[DavidProehl]

So are you saying it is ok if the OT isn't in the evaporator tube all the way as long as I can screw on the metal hose that connects to the evaporator? I may be able to do that much. I'll give it a try.

[WelmoedJ]

If you're putting the orifice in the way it is taped to the pipe, it's the wrong way.
The conical end should go in first (into the pipe), the square eye should be pointing towards the dryer (accumulator).

[Bitsyncmaster]

If you're putting the orifice in the way it is taped to the pipe, it's the wrong way.
The conical end should go in first (into the pipe), the square eye should be pointing towards the dryer (accumulator).

I think your wrong but the OT is just a tube so it works either way. That square end is what you pull it out with.

[WelmoedJ]

I think your wrong but the OT is just a tube so it works either way. That square end is what you pull it out with.

You're right about the pulling.
However as the OT has to be put into the pipe, my afore statement sticks.
I've assisted in the replacement of a couple of OTs in several D's and the way I described it, has been the way we did it.

[dmc6960]

The orientation in the original picture is correct...

http://www.autoacsystems.com/fasttrack/orificetube/A5100_GMOrificeTube.jpg

[Ron]

Look on the orifice tube there is usually a small arrow pointing in the direction of flow. You cannot go by the tab or tabs to pull one because some go in the condenser pipe and others go in the evaporator pipe, like a De Lorean. The tubes are sometimes tapered too! If no arrow, the answer is that the larger screen ALWAYS filters incoming refrigerant. The smaller screen is a backup (for if/when the large one bursts).
So the orientation in the photo is correct.

If you can't get it to go in and you are 100% certain you have the right size diameter OT, usually the tube is defective, twisted or otherwise abused. Since this one is new and it goes in part way, I would suspect the former more-so. In any event, I would try this. DO so at your own risk ;-) :
Remove the O-Ring and see if the OT will go in easily all the way, If so try the O-ring if it is not hard etc. If not, you can take a tapered rod and gently tap it into the tube while FIRMLY holding the tube BEHIND THE CRIMP -- DO NOT allow the tapping force to travel the tube or you may cause the evaporator to leak! You must be certain not to use a rod that is too big else you will be screwed looking for a OT to fit.

[dmc6960]

Check if there is any curve in the evaporator pipe where the orifice tube goes. If there is any kind of bend at all, it will make it extremely difficult to install the orifice tube, just like you have experienced. Try straitening it out.

If it already is completely strait, try more oil.

[Ron]

I think there is an echo in here Jim. LOL

[WelmoedJ]

The orientation in the original picture is correct...

http://www.autoacsystems.com/fasttrack/orificetube/A5100_GMOrificeTube.jpg

My bad, guys!
I didn't notice that until the large picture was entered.
Apologies to all.

Let's try and do it better in 2012.

[DavidProehl]

Thanks Ron & Jim.

Here is a better picture of how far it slides in.
http://i.imgur.com/jjjZGl.jpg

My pipe looks straight, not sure how I would straighten it any more. I originally tried installing this when the evaporator was outside the car (before I had a chance to possibly bend it in any way), but had the same issue. I figured it was because I didn't have lubricant. I now have lube, but things are more difficult since the evaporator is installed.

I didn't quite follow the tapered rod suggestion, are you talking about using something like this to tap it in?

Tapered rod:
http://www.supplierlist.com/photo_images/188353/MAXDRILL_Tapered_Drill_Rod.jpg

[Ron]

I guess it goes w/o saying but the rod I mentioned above should be tapered on the end only...:bang:

=======
LOL WelmoedJ



EDIT: MAN, I'm having bad timing today lol.

The rod MUST be round! ...you would be reshaping the tube. I hesitate to say because if it gets stuck you will hate me lol, but first time I did it years ago, I went through some deep well sockets (because they are tapered) and an extension that locks onto it... I do a lot of AC work so I wound up making one out of an extension. Like I said before there is a crimp in the tube that the OT butts up against. No need to go that far -- if you spread it open, the evaporator will eat the ot. I said to hold behind the crimp so as not to distort the area that the OT goes in any further. Use lots of AC oil! Got me?

[Soundkillr]

Yea dont open the crimp. I once got one that had a bad crimp. I knew i shouldnt have installed it, but the vendor assured me it would be ok. Got it charged and 30 seconds later it sucked up the orafice tube. That was fun. Got to do the whole job over. I wasnt happy.



I guess it goes w/o saying but the rod I mentioned above should be tapered on the end only...:bang:

=======
LOL WelmoedJ



EDIT: MAN, the I'm having bad timing today lol.

The rod MUST be round! ...you would be reshaping the tube. I hesitate to say because if it gets stuck you will hate me lol, but first time I did it years ago, I went through some deep well sockets (because they are tapered) and an extension that locks onto it... I do a lot of AC work so I wound up making one out of an extension. Like I said before there is a crimp in the tube that the OT butts up against. No need to go that far -- if you spread it open, the evaporator will eat the ot. I said to hold behind the crimp so as not to distort the area that the OT goes in any further. Use lots of AC oil! Got me?

[Bitsyncmaster]

You're right about the pulling.
However as the OT has to be put into the pipe, my afore statement sticks.
I've assisted in the replacement of a couple of OTs in several D's and the way I described it, has been the way we did it.

Now that I see the photo (I'm at home)....It does show it backwards from the way I install them,

[Bitsyncmaster]

I had one break off with nothing left to grab. I pressurized back at the compressor and blew it out with about 100 PSI.

[Ron]

Yea dont open the crimp. I once got one that had a bad crimp. I knew i shouldnt have installed it, but the vendor assured me it would be ok. Got it charged and 30 seconds later it sucked up the orafice tube. That was fun. Got to do the whole job over. I wasnt happy.Knowing you, I'd like to have heard the next phone call LOL!!!

No need to get that close to it because there is plenty of room even on the short side. In this case I would keep tapping and checking until I knew the hose would never hit the OT plus a tad and move on... If the pressure ever moves it, the crimp will grab it.

[Soundkillr]

....Twas a fun phone call!:swear1:


Knowing you, I'd like to have heard the next phone call LOL!!!

No need to get that close to it because there is plenty of room even on the short side. In this case I would keep tapping and checking until I knew the hose would never hit the OT plus a tad and move on... If the pressure ever moves it, the crimp will grab it.

[DavidProehl]

Now that I see the photo (I'm at home)....It does show it backwards from the way I install them,

Dave - Are you saying the photo in my last post has it in backwards? I can definitely slide it in way further, and very easily, if I flip it around. All the previous posts though indicate I'm installing it the proper direction.

[Bitsyncmaster]

I just went out to look at an old orifice tube (used). And it does have trapped "dirt" on the long screen side of the tube. So the long side is indeed the inlet as shown in the later photo. You only need to insert the OT until the O-ring seals. Don't force it in to far or you will be sorry when you can not remove it later.

[Bitsyncmaster]

Dave - Are you saying the photo in my last post has it in backwards? I can definitely slide it in way further, and very easily, if I flip it around. All the previous posts though indicate I'm installing it the proper direction.

Your photo shows it correctly. I must have been remembering another car I worked on.

[Ron]

I had one break off with nothing left to grab. I pressurized back at the compressor and blew it out with about 100 PSI.My little stainless friend.

7483

[dmc6960]

I dont know what your condenser>evap hose looks like, but if it will attach there without forcing the orifice any more it should work like that.

I remember more evap hose sticking out of the firewall though.

[DMCTek]

You do have to OT in the correct direction. It should also go completely into the evaporator.
Some go in easy and others are a struggle. There is a tool to aid install. I have broken these myself, the tool can help a lot. You should be able to find one at a Napa or Carquest. If you have trouble finding one I can send a photo of ours or try and locate one for you.

[DavidProehl]

You do have to OT in the correct direction. It should also go completely into the evaporator.
Some go in easy and others are a struggle. There is a tool to aid install. I have broken these myself, the tool can help a lot. You should be able to find one at a Napa or Carquest. If you have trouble finding one I can send a photo of ours or try and locate one for you.

Thanks for the tip, I had no idea there was a custom tool for this. Is yours similar to this: http://www.autozone.com/autozone/accessories/Tools-Garage-and-Equipment/Orifice-Tube-Remover-and-Installer/_/N-262y

[Ron]

FWIW- I have a set similar to that. They have been sitting in the same place in my recovery station cabinet for years...As an extractor, if the pipe is distorted rather than dirty, my experience is that the tool will just break the tabs off. It's simpler to gut what you can with needle-nose pliers and use a long screw. When you pull the metal tube out it leaves a perfect pilot hole...
As an installer, you don't need it at all if the pipe is not out of shape. If it's so bad that you are breaking one with new 'plastic', forcing it in there can ruin the o-ring on the tight sides and/or leak on the other, a SOB later.
I guess it's worth a try if you don't get carried away, but it seems to me that you ought to reshape the pipe -- fix the problem rather than use the 'get a bigger hammer approach'.

Different strokes I guess...

[David T]

There is a picture in the Workshop Manual at N:02:02 fig 16 & 17. Good luck using them! If the tube is going to be difficult you will be digging it out in pieces. Not a good thing to have to do with that soft aluminum pipe. VERY easy to puncture the pipe and now you're f-cked! As for installing, if it doesn't go easily the pipe is bent or otherwise distorted. You can try rounding it with a round tool close to the internal size of the pipe. Again, you must be REALLY careful with the soft aluminum pipe. If you just bought all of this stuff you should be talking to the vender you bought it from. BTW most orifice tubes were installed and then the pipe was bent installing the evaporator into the car. It is VERY difficult to remove the old tubes once the pipe is bent. If you do not know what you are doing it is probably best to just leave the old one in if the inside of the system looks clean. I have heard of some people trying to fry the old ones out with a heat gun. I have not tried that myself (yet).
David Teitelbaum

[DMCMW Dave]

This is the tool we use to put it in. You may need to cut a couple of the tabs off the end of the tube as the "long end" goes into the tool. This presses it in at the bottom near the o-ring so you don't break it.

7505

[Ron]

You may need to cut a couple of the tabs off...So you guys are the ones...:devil:

[DavidProehl]

This is the tool we use to put it in. You may need to cut a couple of the tabs off the end of the tube as the "long end" goes into the tool. This presses it in at the bottom near the o-ring so you don't break it.

7505

Dave - Where can I find a tool like that? Haven't come across anything like that while searching.

EDIT: To be more specific, I've seen tools like that, but with the notch towards the end of the tool rather than the handle like your photo. Such as this one: http://www.amazon.com/Great-Neck-Orifice-Tube-Tool/dp/B004FEHXXO

[DMCMW Dave]

Dave - Where can I find a tool like that? Haven't come across anything like that while searching.

EDIT: To be more specific, I've seen tools like that, but with the notch towards the end of the tool rather than the handle like your photo. Such as this one: http://www.amazon.com/Great-Neck-Orifice-Tube-Tool/dp/B004FEHXXO

I honestly don't recall, it just kind of showed up in the shop maybe with one of the techs. Which means it probably came from Snap-on or Matco. But I couldn't find it online just now.

[Ron]

There is a picture in the Workshop Manual at N:02:02 fig 16 & 17. Good luck using them! If the tube is going to be difficult you will be digging it out in pieces. Not a good thing to have to do with that soft aluminum pipe. VERY easy to puncture the pipe and now you're f-cked! As for installing, if it doesn't go easily the pipe is bent or otherwise distorted. You can try rounding it with a round tool close to the internal size of the pipe. Again, you must be REALLY careful with the soft aluminum pipe. If you just bought all of this stuff you should be talking to the vender you bought it from. BTW most orifice tubes were installed and then the pipe was bent installing the evaporator into the car. It is VERY difficult to remove the old tubes once the pipe is bent. If you do not know what you are doing it is probably best to just leave the old one in if the inside of the system looks clean. I have heard of some people trying to fry the old ones out with a heat gun. I have not tried that myself (yet).
David Teitelbaum
+1

=================

RE: "now you're f-cked!" (Morning After pill, by Master Cool ;-)

7518

[Bitsyncmaster]

Just on a side note. If you’re using the VOV type orifice, make sure your tube is straight. Any bend will mess up the operation of the VOV. And if you get it stuck and want to remove it, it has no easy hole to use a screw to extract it.

That is when I had to blow it out with pressure.

[DavidProehl]

I want to post my resolution to this. Took me some time to work through it so I might as well document it!

I ordered the Orifice Tube installer/remover I linked to earlier, turns out it is only a remover :(

That left me looking for Dave's tool:


7505

I couldn't find it anywhere. So I went to Home Depot, and bought some 3/8 inch copper tubing. Yes, it is very soft, but I didn't want to apply a lot of pressure to the orifice tube anyway.

With a Dremel, I cut out slits for the sides of the orifice tub to go in, similar to Dave's tool. This is what I ended up with:

http://i.imgur.com/BTBTg.jpg

I slid this on the orifice tube such that it rested at the base of the filter, placed a piece of wood at the end of the tool and lightly tapped. Presto! Slowly but surely it slid in. It is now properly inserted.

I'm finally closing up my A/C system! Can't tell you how difficult that tube was to install without the right tool. Only took 2 minutes to install it once I had my homemade tool ready to go.

[DMCTek]

Bravo! Nice work. The tool has worked every time for me as well. I like the fact that yours is soft. If I do fiqure out where ours came from I will pass along the info.

[kings1527]

I want to post my resolution to this. Took me some time to work through it so I might as well document it!

I ordered the Orifice Tube installer/remover I linked to earlier, turns out it is only a remover :(

That left me looking for Dave's tool:


I couldn't find it anywhere. So I went to Home Depot, and bought some 3/8 inch copper tubing. Yes, it is very soft, but I didn't want to apply a lot of pressure to the orifice tube anyway.

With a Dremel, I cut out slits for the sides of the orifice tub to go in, similar to Dave's tool. This is what I ended up with:

http://i.imgur.com/BTBTg.jpg

I slid this on the orifice tube such that it rested at the base of the filter, placed a piece of wood at the end of the tool and lightly tapped. Presto! Slowly but surely it slid in. It is now properly inserted.

I'm finally closing up my A/C system! Can't tell you how difficult that tube was to install without the right tool. Only took 2 minutes to install it once I had my homemade tool ready to go.

Dave,

I'm going through the same thing right now. I tried the copper tubing trick and couldn't get it to work. Did you have to trim any tabs off the orifice tube in order to get the copper tube to fit correctly on the base of the hub of the orifice tube?

Thanks in advance!

[DMCMW Dave]

Dave,

I'm going through the same thing right now. I tried the copper tubing trick and couldn't get it to work. Did you have to trim any tabs off the orifice tube in order to get the copper tube to fit correctly on the base of the hub of the orifice tube?

Thanks in advance!

Sometimes. The only thing "critical" is the o-ring seal, if the plastic bumps are too big cut them down.

[kings1527]

Sometimes. The only thing "critical" is the o-ring seal, if the plastic bumps are too big cut them down.

Gotcha. I think that's what I needed to hear.

As always, thanks again for all the great info, Dave!

[DavidProehl]

Sometimes. The only thing "critical" is the o-ring seal, if the plastic bumps are too big cut them down.

In my case I didn't need to trim the tube, but listen to Swingle, he knows better than me!

[82DMC12]

I'm resurrecting this thread from the dead because it's absolutely golden and got me out of trouble!

I am in the middle of a total A/C replacement and already broke two orifice valves. It seems like they just would not go in more than an inch, just like David's. I had been tapping on the long screen part and I kept damaging them. I bought extra Corvette valves (a whole $1.99 each at Advance Auto) because they seemed more likely to go in than the Variable valve I got from Hervey way back.

Anyway I found this thread and made a tool just like it - success!

I found that I had to cut a slot about twice as thick as a dremel heavy duty cut off wheel. To make the white valves work you would have to also shave off the tips that allow for the extraction tool. It took some trial and error cutting the slot just right so that the valve would slip into it easily without making the tube spread apart at the orifice-contact side. That wouldn't be good since it would just get jammed up in the evaporator.

First I made sure the evap tube was straight as possible by gently inserting a big punch and carefully bending the tube into place. It was maybe 2 mm off center. I don't know if made a difference or not but I figured since I was having so much trouble it was worth the effort.

I oiled the valve liberally and put oil on the copper tube. I was then able to tap in a white valve fairly easily. Once the valve is inside the evaporator tube, I used a needle nose pliers to pull out the copper piece. This left the valve in place and I was able to tap in it the final 1/4" with no problems.

Actually it worked so well that I ended up pulling out the first new valve with a needle nose, and then tried it again with the Variable valve since I think that one will be better. It was a bit more tight probably due to two O-rings but it worked.

Thanks to David and this thread I now have my VOV installed. Here's a picture of the tool and VOV.

http://i.imgur.com/1LKMgN7.jpg

Andy

[DavidProehl]

Nicely done Andy! Glad this trick worked for you!

[Farrar]

I didn't have any copper pipe, but was able to install the VOV using the hard plastic tube from a ball point pen I had lying around.

[DMC-81]

I am reviving this thread to get some feedback: For those of you that opted to install the variable orifice tube/ VOV, does it fit in our application the same as the original tube? Any considerations other than the second o-ring? Is it equally effective in R12 and R134a refrigerant?

Aside from installation, how do you like it? It seems like it is a simple upgrade that has some advantages, especially in a hot climate. Or is that hype?

Thanks!

[DMC5180]

Hi Dana,

I never experienced my D with R12. The system didn't work when I acquired it in 94. When I did take it to a shop for repair in the late 90's the guy said, he no longer did R-12 servicing and was just doing 134a conversions. That guy told me he installed a ford spec orifice tube, he said those seemed to perform a bit better with 134a conversions. Hard to say if it did or not, since I had nothing to compare it with. The one issue that still remained was a very slow leak. The guy told me the evaporator was likely suspect since the inlet pipe had been damaged trying to remove the Orifice tube and there was internal pit corrosion. For the next decade I Limped it along, by adding refrigerant just before any planned trips. In 2010 I finally had had enough and took the plunge into an EVAPORATOR replacement. At that time, I figured as long as I'm in there, I might go with the "VOV" figuring it won't hurt anything and if I can get 5-6 degrees cooler performance at idle, why not try it. Does it make a marked difference? I can't tell, I didnt' do a before and after test. Once the initial solar heating of the interior has been over come, I tend to switch back and forth between Fans speed 1-2 to maintain comfort levels depending on cloud cover. I have an IR/UV windshield which makes a substantial difference in heat transmission. The door windows, however, can be a solar cooker. Especially certain times of day and direction of travel.

The difference in price is between a standard replacement orifice and smart VOV is about $20.

As for installation issues, I found I could not install it with the O-rings that came with it. The O-ring cross section diameter was too big. I installed slightly smaller ID O-rings with a smaller cross section. Once in the groves, the OD's were about 1/4 (cross section) proud of the VOV body diameter. I made an installation tool out of some scrap aluminum tube at my work. Basically cutting it lengthwise with a band saw. So it would fit over the VOV inlet screen and push directly on the VOV body. The VOV installed easily with a little Pre-lubing of the O-rings with refrigerant OIL.

[82DMC12]

Hi Dana,

I'm like Dennis, It's been so long since I had working R12 that I don't remember but I do know the R12 was COLD. The R134a complete conversion I did with the VOV is PRETTY COLD. No matter what system you have, it seems like it takes a good 20 minutes to really cool down the cabin after it's been sitting in the sun all day. Once the cabin starts to cool off I can maintain a good temperature at speeds 1 and 2 no problem just like Dennis, which ultimately is what you are aiming for I think.

All that being said, I prefer my 2014 Audi when the temps in Kansas City are brutal with high humidity. Sorry DeLorean.

Andy

[DMC-81]

Thanks guys for the feedback. It sounds like $20 well spent...

[DMC-81]

So, I bought a VOV, MT0631 from Auto Zone ($22 with a discount). I just want to ensure the it is the right one, because it's seems to be smaller than the pictures....

46291

Or is that my perception?

[DMC5180]

That's the CORRECT one for the EVAPORATOR inlet. They also make a version that's meant to be installed on some CONDENSER outlets. Be sure to wet the O-rings with compressor oil.


Dennis

[DMC-81]

Thanks Dennis. I just wanted to check. I'll be sure to oil the o-rings. I'll also make the copper pipe tool as described above.

Cheers,

[DMC5180]

Thanks Dennis. I just wanted to check. I'll be sure to oil the o-rings. I'll also make the copper pipe tool as described above.

Cheers,

This is my homemade VOV insertion tool. It's 3/8 x .035 aluminum tube.
It slides over the Screen and pushes against the Round section of the white side.

http://uploads.tapatalk-cdn.com/20160917/1144c8337f1a683bf39787d92c15bc54.jpg

http://uploads.tapatalk-cdn.com/20160917/1bfc06e8032a620393255ab8fa9f1385.jpg



Dennis

[Morpheus]

^Dennis, you could probably make and sell those for people... I know I'd buy one.

[DMC5180]

I just took the tube and ran it through a vertical band saw. Then dressed the slot with a micro file followed by edge debuting. Although you don't see it in the photo the tube is about 6 inches long.

The orifice tube insertion and removal tools I've found online don't work like this one. They are for orifice tubes that have "ear tabs" that the tool hooks around to pull on. I wasn't able to find one that worked the way I wanted it too. So, I made my own.


Dennis

[DMC-81]

Thanks again Dennis for the tips on making the tool. :wrenchin:

I agree with Brandon that it is a great product idea.

[L3V3L1]

Can anyone tell me if this is a broken orifice tube? It's 2 inches into the evaporator pipe.68831
And how can I get it out?
Thanks

[82DMC12]

Sure looks like it to me

[Ron]

Get one of these: https://www.centurytool.net/Gm_Ford_Screen_Extractor_p/msc91009.htm

Or you can use a screw. Either way, make sure you run it eight down the center to avoid piercing the tube.

[Bitsyncmaster]

I used air pressure to blow mine out. If your orifice is plugged little air is needed if not you need more air flow but the hole is pretty small so still should work.

[dmcman73]

Since the thread mentions the variable orifice tubes, those that have installed one, are they noisy as some owners have stated them to be?

[82DMC12]

Since the thread mentions the variable orifice tubes, those that have installed one, are they noisy as some owners have stated them to be?

I have never noticed this.

[dmcman73]

I have never noticed this.

Good to know. I have a variable one and just the plain regular GM one, deciding which one to install. I've read that owners that did install a variable one could hear a very noticeable whine in the system as the pressures changed.

[82DMC12]

Good to know. I have a variable one and just the plain regular GM one, deciding which one to install. I've read that owners that did install a variable one could hear a very noticeable whine in the system as the pressures changed.

I have the black GM variable valve in and I've never noticed any "whine" while driving. I can hear it bubbling when I park in my garage and shut the car off sometimes though.

[Ron]

Good to know. I have a variable one and just the plain regular GM one, deciding which one to install. I've read that owners that did install a variable one could hear a very noticeable whine in the system as the pressures changed.If you are going R12, use the GM. I've never used a variable on a D...mixed stories, mostly not good....

[82DMC12]

If you are going R12, use the GM. I've never used a variable on a D...mixed stories, mostly not good....

I'd like to learn more about this subject. My A/C is "fine" but of course not as effective as my daily driver (Audi Q5). I'm not sure if the A/C can work any better than it already does. I've converted to R134a with a new compressor (Sanden SD5H14), a parallel flow condenser, new dryer, the VOV, and replaced all the hoses front to back with the kit from Hervey a few years ago. The only part that's original is the evaporator.

Is a single-orifice valve better? Also I heard there's a SD7 compressor that's "better" but how much better is not clear.

I'm going to open up my A/C next week for major frame service so now's the time for further upgrades.

[dmcman73]

I'd like to learn more about this subject. My A/C is "fine" but of course not as effective as my daily driver (Audi Q5). I'm not sure if the A/C can work any better than it already does. I've converted to R134a with a new compressor (Sanden SD5H14), a parallel flow condenser, new dryer, the VOV, and replaced all the hoses front to back with the kit from Hervey a few years ago. The only part that's original is the evaporator.

Is a single-orifice valve better? Also I heard there's a SD7 compressor that's "better" but how much better is not clear.

I'm going to open up my A/C next week for major frame service so now's the time for further upgrades.

One other piece of info I was told when converting to R134a, from some other owners, was to adjust the low pressure switch using the screw that is in-between the prongs of it. The right way would be to adjust it using pressure gauges (I don't remember the specifics), or, a generic way is simply turning it one full rotation counter clock wise. It supposedly helps a lot.

[Bitsyncmaster]

I'd like to learn more about this subject. My A/C is "fine" but of course not as effective as my daily driver (Audi Q5). I'm not sure if the A/C can work any better than it already does. I've converted to R134a with a new compressor (Sanden SD5H14), a parallel flow condenser, new dryer, the VOV, and replaced all the hoses front to back with the kit from Hervey a few years ago. The only part that's original is the evaporator.

Is a single-orifice valve better? Also I heard there's a SD7 compressor that's "better" but how much better is not clear.

I'm going to open up my A/C next week for major frame service so now's the time for further upgrades.

One thing I found that really improved the AC cooling is to open that condensation drain. The OEM design has that elbow crimped I guess to try to reduce air flow loss but it makes the drain plug up and the water in the evaporator box blocks air flow over the evaporator.

I removed the OEM drain and did the "Bill" fix to use a coil boot. I added a normal elbow to a hose running to a drain hole drilled in the floor. That also keeps the water off the frame.

[Ron]

I'd like to learn more about this subject. My A/C is "fine" but of course not as effective as my daily driver (Audi Q5). I'm not sure if the A/C can work any better than it already does. I've converted to R134a with a new compressor (Sanden SD5H14), a parallel flow condenser, new dryer, the VOV, and replaced all the hoses front to back with the kit from Hervey a few years ago. The only part that's original is the evaporator.

Is a single-orifice valve better? Also I heard there's a SD7 compressor that's "better" but how much better is not clear.

I'm going to open up my A/C next week for major frame service so now's the time for further upgrades.My experience and research over the years: R134a has a lighter molecular size, lower heat transfer rare, requires a larger condenser, runs at higher pressures, and results with ~5°F lower output air (in a D)...~15% less efficient.

The only reason I know some use variable orifices, in a D, is because of R134a's higher pressures.
The Saden SD5H14 & SD7H14 have a good rep - Beware of knockoffs!

Seems your setup should be OK for KS,
(R12 would do better, but you would have to use a quality flush and a different type oil....)
Generally, a system is OK if:
70°F, 20% humidity, 35-40°F at vent...
80°F, 90% humidity, 45-50°F at vent.

[David T]

The best advice is to try to stay with R-12 as long as you can. The system was designed for it and any other refrigerant is not going to have the cooling capacity of -12. If you can't get -12 the next best choice is R-414b. It is a drop-in blended replacement but should not be used in a leaky system because you can only "top off" twice, after that you mess up the blend proportions. Finally we have -134. To use it you must flush the system, change all of the hoses and "O" rings, drain the oil from the compressor and refill with the correct stuff, change the service ports and accumulator, and adjust the low pressure switch. After all of that you lose about 10% of your cooling capacity. In a place like Florida you will notice it on a really hot day.