R134a Conversion

[R Dubya]

I just did this over the last week or so, so it's still fresh in my mind, and I'd like to post this for anyone with the ambition to properly convert from R12 to R134a. 

You will need to replace all the seals that you see on the picture below, (2, 3, all the 9's, both 26's and 36 maybe more that I am not seeing right now)then have the system vacced down, new PAG oil for the compressor and of course the 134a.  Removing the turbo will make it easier to get to the seals on the evap core on the firewall, as well as replacing the tube and the oring that seals that fitting, but it is not neccessary.  I did not replace the seals on the evap core behind the dash, as I have a PMIII and was not going to remove that to get to those 2 orings.  If they leak, I will consider it, but I am betting the house that they wont, at least for a while.

http://smg.photobucket.com/albums/v216/Rw89TGP/TGP%20Pics/?action=view&current=scan0001.jpg

#10 (orifice tube)should either be removed entirely, or replaced with a brand new unit.  Do not leave the old one in there, it will cause a bit of blockage and will torment you to no end if you do not. 

After replacing the o-rings on the compressor, and on the compressor lines, I changed the accumulator (#20) with 4 Seasons aftermarket part #33206 (thanks for the research Brian), which includes a low side port.  The service manual says the turbo has to be removed to properly service the A/C system, and with the 134a fitting on the pipe you cannot get the service valve on to charge it.

This new drier makes charging this system EASY!!  I attached the new high side service port to the condenser tube (#8), then I changed the oring at the condenser, and then the oring at the connection right below the turbo, right after #8.  You also need to keep in mind you have to remove the valve cores from the R12 service ports, (at least I did with my Carquest conversion kit), otherwise the system will not take the charge.

Most of the line female fittings are 7/8" and the male correspondents at 3/4".  Other than that this job is straight forward, and in one quick swoop about 3 hrs of work.  R134a is about $80 cheaper per pound, and a lot friendlier to the environment.  So I did it as mine was empty, you should to if you are in the same boat. 

 

[TGPilot]

Awesome write-up Ryan! I will make this a sticky.

Thanks much!

-Kenny

[pontiac6ksteawd]

You are more than welcome on the research. I am having to re-retrofit my system this year cause I put a hole in my drier tank :(

you forgot to replace the O-rings for tank. Numbers 34 and 35

[LukeZ34]

Yup, nice info to have. It keeps people from buying the 'death kits' at wally world and filling their system without doing any work to it.

I'll ne doing this same thing here within the next few weeks. I'll be sure to post some pics to go along with the write up.

[R Dubya]

You are more than welcome on the research. I am having to re-retrofit my system this year cause I put a hole in my drier tank :(

you forgot to replace the O-rings for tank. Numbers 34 and 35

new o-rings came with the tank, but good point.   

Not a bad job.  Good deal on that drier and my a/c was blowing real cold today, it took a while for it to cycle, but once I ran it for 10 minutes or so, it started to get much colder.  I didn't temp it at the vent but it was definetely below 40*. 

[R Dubya]

well, its still charged but stopped blowing cold, so I am thinking that the orifice tube is causing some problems, so I will be removing it for the last time and not looking back,  , after this thing get vacced down for like a half hour and then we will see if its working, I may possilby need a new compressor, we will see. 

Interesting, and yet extremely frustrating.  This car will be the death of me.  I swear it.


REMOVE THE ORIFICE TUBE!!!!  DO NOT REPLACE IT!!!

[mfewtrail]

Ryan, did you replace the orifice tube with an original style tube(or one meant for R-134a)? Also, where did you get the idea of removing the orfice tube completely?

[pontiac6ksteawd]

Thats what I am wondering. All air conditioning systems have some sort of orifice. Doesnt matter if its home, car, or what type of freon. Not sure where he got that idea..

I found my leak, one of my hoses coming off the AC compressor blew, had some dye in it and saw the blown remains all over the lower core support and cooling fan, and everything else down there (except the radiator, just replaced that).

[R Dubya]

Well, the techs at work recommended that I remove it entirely so as not to clog the system with any debris that may be in there, but I found out today that the compressor is toasted.  It is leaking horribly from the center of unit, I am thinking that the large o-ring was just dried out and its useful life was over. 

I assumed that the tube was causing a blockage, but its not.  Strangely enough the compressor was still kicking on but only hada about .07 lbs of refrigerant.  So we were trying to find the leak and we did, a spot of oil and dye right on the bottom of the compressor.  Time for a replacement.    

[mfewtrail]

Well, the techs at work recommended that I remove it entirely so as not to clog the system with any debris that may be in there, but I found out today that the compressor is toasted.  It is leaking horribly from the center of unit, I am thinking that the large o-ring was just dried out and its useful life was over. 

I assumed that the tube was causing a blockage, but its not.  Strangely enough the compressor was still kicking on but only hada about .07 lbs of refrigerant.  So we were trying to find the leak and we did, a spot of oil and dye right on the bottom of the compressor.  Time for a replacement.    

I would think removing it completely would result in lackluster ac performance due to allowing the refrigerant to enter/move through the evaporator at a much quicker rate where it wouldn't absorb as much heat(after all, the orifice tube is there to meter the amount of refrigerant entering the evaporator and since it's a restriction, it creates a pressure drop at the evaporator that allows the refrigerant to vaporize at a lower temperature.) Also, it does catch debris inside the ac system as you mentioned, so it's recommended to replace it when you're replacing major ac components.

[pontiac6ksteawd]

Just wondering if we can modify the original post on this, as the spring time A/C season is about to open. Need to take out the part about removing the Orifice, since thats a bad idea. And also to use a dye type freon when recharging so if/when it looses its freon, its easier to track and fix the problem.

EDIT: Found out from a friend of mine who does AC Systems as his profession, that the Orifice tube is not only needed, that its required. The orifice, while slowing down the flow of freon, also creates a flash point inside the system going from the HOT to COLD. With the Orifice missing, the AC system will work, but it starts using the drier as the orifice, and since the drier is so large, its cooling efficiency drops to about 10%.

[R Dubya]

and yet again, I would ask that you please read two posts above your last, and I would also like to thank the person that bold printed my assumed.

I was given that recommendation by a GM tech at the shop I worked at, since it was a conversion from R12 to R134a I was told it was not necessary, required, etc. 

Apparently I posted my recommendation a bit too soon, I never removed it, did replace it, thought that the orifice was creating a problem but it turned out that the reman compressor I bought to replace the OEM was shot as well and leaking. 

redundant is the word I am searching for.

[pontiac6ksteawd]

I was only making that suggestion cause you know how some people are, they read the post that most interests them, and forgets the rest...