Hey we know the summer is around the corner. I have a baby on the way. I was woundering if any body has done this putting 134a in a r12 system. The system was unhooked when i got the car. I hooked up and should i put freeze 12 in or go to autozone and buy the 134a conversion nossles. If so how cool does it run. I'm in Texas and the heat can cook an egg on my drive way.

 

im in AZ. have r 134 in mine, works fine if you do EVERYTHING to do the conversion, it needs some different oil, and the presure cylcing switch changed as well as it takes less r 134 then r 12

 

what do you pressure switch change to what? Are there different one with other settings.

 

the presure switch is located on the acumulator/dryer thing that come right off the evap core, its got two wire going to it and u pull the conecter off and there is a flathead scree in it you turn 3/4 of a turn counterclockwise (im 99% sure) its that way

 

How cold does your car ac outlet get?

 

i havnt checked when it was like 110 out but it was like 95 outside and it was blowing low 40* air out.

 

The most important thing is to put the correct oil back in the system. If you dont the whole system wont last long. R134 operates at a higher pressure than R12. I dont know if our cars have the adjustable low pressure switch like fords do. I tweaked them when doing R134 conversions on fords.

If the system was open to air for any amount of time, or not sealed, you need to replace the accumulator since the dessacant in it is probably bad from being in an open system.

Also, if you want a good functioning conversion, you need to replace the orfice tube with a variable unit. The variable unit will probably be about $50 but it is worth it. There is R134 specific orfice tubes that will be much less money.

Since the system is open anyways, it would probably be a good idea to replace all the o-rings in the system. Be sure to lube any o-rings with either pure silicone oil, or system oil before installation.

Pull a good vaccum on the system and let it sit for 30 min before charging anything. Make sure you put dye in the system in case you didnt fix the leak.

You can charge by looking at the low side pressure, but you risk over charging the system. I usually will charge a R134 system based on the high side pressures with engine about 2,000 rpm. Depending on the ambient temp that can be anywhere from 225 to 300.

 

o ya i forgot orfice tube, i used the ford blue one

 

On my car the compressor was just unplug. So i still have to replace all of that.

 

From what I've been advised and reading the various manufacturers web sites, the ester type oil will co-exist with the R12 type oils but the PAG type oil wont. Also, the pressure cycling switch should be turned 1/4 turn counter clockwise to start with so that the low side pressure with R134 is 21-22psi.

https://www.thirdgen.org/retrofitac

 

There's a bunch of how to videos on the net. Plus diagrams of the different a/c system types and components etc. etc.

 

Do I need to vacum on the system try do all this my driveway with limited number of tools?

 

You can get a little vacuum pump from Harbor Freight for $80~$90 that will do the job. I would run it for 1 to 2 hours if you've had the system open to remove all the water vapor before you start re-filling it. I agree with the other posters that if the system is already open, take it apart, flush out the old R12 oil, replace the dryer, orifice tube, o-rings, change to R134a fittings and put in new PAG oil.

 

You can also get a cheaper compressor operated one, but they are slow and need to pull vaccum for a long time to get all of the moisture content out.

This is definately a driveway job. Simple hand tools is all you need. In fact you can do everything with a large adjustable cresent wrench, a medium cresent wrench, needle nose pliers for the orfice tube (they make a tool, sometimes they get stuck from crap in the system clogging them up), pick for the o-rings, and prefferably a set of A/C guages. All of this can be had for pretty cheap from harbor freight. Probably about the same amount as paying someone to do it.

 

I have the dreaded slow leak. Of course the cars been garaged its whole life, so who knows what the hell is going on. 13 years not being started or cared for. Seems like it's easier for the mechanic to do it. At least i'll know that it's done right(hopefully) If it costs the same why not.