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Discussion Starter #1
I just ordered a Robinair vacuum pump (already have manifold gauges) and I am going to convert to R134a in my 91 L. I will need to order a 134a expansion valve for a 94 - 95 model and a receiver dryer, which I understand is the same for R12 or R134a, right? I am going to save money for now and use the original condensor and see how it does. Crossing my fingers that my compressor is good, which it should be. The last time I had it off the car, I emptied it of the old oil and put in Ester oil in preparation for the R134a. The manual said to fill it to 70% of capacity, if I remember right, which I did. The low side valve is very close to the hood, so I guess I will have to use a 90 degree R134a adapter? Anybody know what size adapter I need for the high side? Thanks, I have been driving home in 103*F weather (my ext temp on my console went up to 111*F one day!) and I am feed up! :eek: Oh, and I will replace my seals with the green ones.
Charles
 

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Discussion Starter #2 (Edited)
How well will this work with the original expansion valve? Maybe I should just buy a set of A/C hoses from a '94-'95 from APE? Will they bolt right in and make for the utimate retrofit job?
Charles
 

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1. Don't expect 134a to cool as well as R-12 no matter what you do.
2. To give 134a the best shot, buy a 134a expansion valve.
3. Dryers are refrigerant specific. Get one for 134a.
4. You only have to replace seals on fittings you disconnect.
5. There's enough room for straight adaptors, you don't need angle ones.
6. For your hot weather, I'd stick with R-12. There's not that much difference in the price of R-12 and 134a.
 

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How well will this work with the original expansion valve? Maybe I should just buy a set of A/C hoses from a '94-'95 from APE? Will they bolt right in and make for the utimate retrofit job?
Charles
Replace the expansion valve with a New one, they are all R134a now and will work with R12 but not the other way.
I found out that problem just recently when my new expansion valve crapped out on me, I used my old r12 and it produced higher temps. Finally replaced with a new R134A and I am getting 38˚F from the vents on a 100˚F + day.
I suggest buying the 24V hoses, flushing them several times with mineral spirits, both ways, also flush evap (not POA valve though) . Replace R/D (R134 specific so 24V), Expansion valve, HNBR o-rings, pressure switch if you see fit, might as well, POA valve from a 24V as they are calibrated for R134a and the R12 may be OK but you may not get optimum results.
You may be OK with existing condenser if not clogged and fins in good condition. May want to get a fin straightner and try to flush condenser while your at it to clear any debris!
You can't use the 24V hose from POA to compressor though.
I used the compressor to cond and cond to R/D.
I was lucky and the POA to Compressor was already r134 rated.

Good luck, you should get good results if done right. Evacuate no less than 1 hour.
Nylog is a good thing to have as well. Put on threads and O-rings for a good seal, also keeps seals from drying out.

Jason
 

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Discussion Starter #5 (Edited)
What is a good flushing system/method? I thought dryers were refrig. specific as well, but I only see vendors selling one, or do I buy one for a '94-'95 model? Thanks for the tip on the Nylog. ;) By POA you mean expansion valve? Can I have my old hoses converted to R134a at a hose supply? Gosh I'm full of Q's.
Charles
 

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What is a good flushing system/method? I thought dryers were refrig. specific as well, but I only see vendors selling one, or do I buy one for a '94-'95 model? Thanks for the tip on the Nylog. ;) By POA you mean expansion valve? Can I have my old hoses converted to R134a at a hose supply? Gosh I'm full of Q's.
Charles
Pour some Mineral spirits in one end while plug the other swish it around to loosen dirt and oil then Push compressed air through it while using a towel on one in to give some back pressure, blow it all out one direction and then do it again the other direction. Several times should do it.

POA valve is the low side valve on the right side of the car next to the timing belt.
To my knowledge with the POA is that when people convert and use the old r12 POA valve which is calibrated to R12 they have less than stellar results.This is one reason why people say you won't have good results regardless. Replacing the unit with the R134 POA from a 24V should result in cooler temps, may only be 5˚F or so but that is huge for an A/C system. Or have your A/C guy adjust the current one you have.

Dryers are all r134 now and can be used for R12 but again not the other way.
To not make any mistakes always order one for the 24V just in-case the vendor still has some old R12 laying around. I think at this point they are all the same though! Sorry for confusion, I said it was specific basically so that you would not get a NOS r12. R134a compatible filters one which contains XH7 or XH9 desiccant
12V-60510695
24V-60590126

If have not done so, Flush the compressor with a "quality" POE oil like BVA Auto 100 and when it comes out clean your done.

You can easily have your hoses converted which will probably be cheaper than APE. No flushing needed at this point.

As long as it is all done properly you should get good results even with the old condenser. But of course I highly recommend to change it as this is one of the main components that needs changing for R134 for best results. Like I said I am getting 38-39˚F from the vents on a 100˚F day, sitting in traffic I get about 40-47˚F.
Just a tip as well, when you first get in, run it on high until circulation comes on then turn it down to 3 speed for best cooling.

Expansion valves are all r134 now. I just had some fun this week changing out mine, I had a bad one, only producing 55˚F maybe 60˚F from the vents, put a new OEM one in and bam 38-39˚F




Hops that helps?
Jason
 

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Discussion Starter #7
Do you sell the R134a POA valve? I haven't seen it listed with any vendors. Thanks for your tips! The only other A/C work I have done was converting my old 190E years ago to R134a and it colded down plenty well with no new parts but a new compressor!
Charles
 

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Do you sell the R134a POA valve? I haven't seen it listed with any vendors. Thanks for your tips! The only other A/C work I have done was converting my old 190E years ago to R134a and it colded down plenty well with no new parts but a new compressor!
Charles
The reason is, it is N/A. Used one is your only choice or calibrate yours and the one I had I used. :)
I may be able to get one for you and maybe all the lines.

In europe they did not use these so Thats another option, you could have a line made with a low side valve in place of the POA and call it a day. The European systems are exactly the same minus this.
Jason
 

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Discussion Starter #9 (Edited)
I found this website interesting on the retrofit. http://www.epa.gov/ozone/title6/609/oneshop.html At the bottom of the page it says "Imports" and talks about adjusting the POA valve adjustment screw one quarter turn counter-clockwise, but this may be for a Toyota or Nissan. I think the cardisc calls the P.O.A. valve an E.P.R. valve? Don't see where you would adjust this thing?
Charles
 

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I found this website interesting on the retrofit. http://www.epa.gov/ozone/title6/609/oneshop.html At the bottom of the page it says "Imports" and talks about adjusting the POA valve adjustment screw one quarter turn counter-clockwise, but this may be for a Toyota or Nissan. I think the cardisc calls the P.O.A. valve an E.P.R. valve? Don't see where you would adjust this thing?
Charles
I think you adjust it from inside. I will shoot a pic today for you where I think you adjust it.

here is a simple conversion chart:
 

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Discussion Starter #11 (Edited)
I thought Ester Oil was the preferred oil to use when doing a retrofit? I assume when all mineral oil has been removed or almost the whole system is new and the rest is thoroughly flushed, PAG oil could be used like in a standard R134a system? I assume the Ester oil I added to the compressor (70% of the compressor capacity) is ALL the oil I need to add for the WHOLE system?
Charles
 

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I thought Ester Oil was the preferred oil to use when doing a retrofit? I assume when all mineral oil has been removed or almost the whole system is new and the rest is thoroughly flushed, PAG oil could be used like in a standard R134a system? I assume the Estaer oil I added to the compressor (70% of the compressor capacity) is ALL the oil I need to add for the WHOLE system?
Charles
According my all my sources PAG is fine. The above info is directly from SANDEN!
http://www.sanden.com/support/RETRO.html
I used PAG

Usually the Compressor can hold around 6 ounces alone. So that should be good enough for the whole system.



I will try to get more info later...
Jason
 

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Discussion Starter #13
Thanks for the link and the info.
Charles
 

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I'm jealous of Jason's 38 degree temp on 134a. I just drove back to Phoenix Monday and the ambient temp read an average of 108 with a high of 113. I just had my compressor filled with refridgerant and it only blew 55 degrees so I was very concerned with how I'd feel on the trip out. Needless to say on full blast it was just comfortable enough! On pos 3 it was not cool enough. I don't have any leaks so I'm not too sure if it's my condensor or another factor but with my black on black leather and factory window tint I need to figure out the problem. On another note, I drove back today and didn't use the air until Yuma. It was in indicated 97 degrees and when I went to use the air it felt really cold, I ran it and 2nd pos all the way to El Centro where it was was 105 and from there to San Diego it was great on 2. I don't know if the extra 5-8 degrees on Monday would account for the difference in cabin temp or is my system running cooler after the outbound trip. Doesn't sound logical does it?
 

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The biggest factor in my experience besides how cool the car is to start out with is the solar gain through the windshield. If you are driving in the direction of the sun shining staright in any car is hard to feel cool in, if you are shaded from direct sun the a/c always seems to perform better.
 

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That has to be a big part of it Alfadue, when I left to Phoenix Monday it was 11 AM and I did get a lot of direct sun into the cabin. This morning on the way back I left at 5 AM just to avoid the big part of the sun. Hence the reason I was able to drive with windows down until Yuma 3 hours away. Still if I was getting even 10 degrees colder out of the vent, say 45 it would have been ok.
 

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Alfa 164 NAPA Low and high conversion fittings R12 to R134

Use NAPA 409903 FOR LOW PRESSURE side at POA valve
Use NAPA 409902 FOR HIGH PRESSURE side at receiver dryer
 

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Discussion Starter #18
Do you have to remove the original valve core for these?
Charles
 

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I'm jealous of Jason's 38 degree temp on 134a. I just drove back to Phoenix Monday and the ambient temp read an average of 108 with a high of 113. I just had my compressor filled with refridgerant and it only blew 55 degrees so I was very concerned with how I'd feel on the trip out. Needless to say on full blast it was just comfortable enough! On pos 3 it was not cool enough. I don't have any leaks so I'm not too sure if it's my condensor or another factor but with my black on black leather and factory window tint I need to figure out the problem. On another note, I drove back today and didn't use the air until Yuma. It was in indicated 97 degrees and when I went to use the air it felt really cold, I ran it and 2nd pos all the way to El Centro where it was was 105 and from there to San Diego it was great on 2. I don't know if the extra 5-8 degrees on Monday would account for the difference in cabin temp or is my system running cooler after the outbound trip. Doesn't sound logical does it?
Don't be. Still bloody hot since I have no tint and black seats. I am waiting for the new tint to come out, the clear stuff like on the Merc.'s that blocks the actual radiant heat up to 75% or something like that.
There are a lot of factors that play with this stuff, ambient temps, humidity, airflow over the condenser, engine compartment temps etc...
I can get up to 55˚F sitting on a semi humid day! but once moving I can get back down to low 40's.


Jason
 

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