So I've done my ac and it is never cold enough. I might get down to 48* down the freeway but at a stop light it gets warm. That doesn't cut it since it's been 110* out lately.

I've run out of R12 and I'm wondering if going R134a can be made to work as cold as R12 should. Since R134a is cheap enough, I can afford to experiment.

I'm thinking or replacing the condenser and make it parallel flow. Would this be enough?

What else do I have to do to make it work perfect?

 

If you want to retrofit to a R134a system, you will need to..
1- recover all R12.
2- flush all the mineral oil out of the system, will require you remove the compressor to flush it out.
3- replace all the 0 rings.
4- replace the filter/dryer.
5- install the correct amount of A/C oil, Ester oil is your best bet, 7-1/2 oz. split between the compressor and the new filter/dryer, also add 1oz of C4 oil to the compressor.
6- install R134a service ports , [don't forget to remove Shradar valves from the R12 service ports befeor installing the R134a service ports.
7- put system under vaccum for a min. of .75hr, longer is better.
8- recharge with 75%-85% of the 34 oz R12 refrigerant charge, you will have to play with the correct amount a little, start with 75% and add .5 oz at a time for the coldest vent temp.

It's a bit of a process to do it right but if you want it cold, it needs to be done.
Replacing the condenser can't hurt, but not needed if there is nothing wrong with it, however, I would replace the expansion valve, at the same time you pull the evaporator to clean debris out of it, [also much easier to flush the evaporator and the rest of the system with the expansion valve removed. 94

 

Depends on your budget, but I would not convert to 134A. Find the leak and fix it. Then, either find some R12 on ebay or do what I did, convert to Freeze12 which is a lot like R12. You can still find Freeze12 refrigerent and oil on ebay at about $40.00/can. Yes it is very expensive compared to R134A, but it works like R12, meaning that you will see very cold vent temps if charged properly. You will never get proper performance with R134A as your system was designed for R12.

I have an 89 Wagon btw.....

 

Not so, although an R12 system will get colder then an retrofitted R134a system, the difference will not make any diff.

Instead of going down to 4 degrees C you will only get 6 degrees C, 42.8F at the vents with a retrofitted system, last time I checked 42.8F is pretty cold.

Also R12 is no longer available in north America, anything now advertised as R12 is an R12 replacement, like your Freeze12 just R134a with an additive that is not compatible with mineral oil or Dura cool or Red Tec and others most are a blend of isopropane and isobutene, both hydrocarbons and flammable and would void any warrant on any new A/C parts installed.

A proper R134a retrofit is the only correct way to go about it, and will save you money in the long run, and is not that expensive if you do most of the labour yourself.

R134a refrigerant is selling for $1.50- $3.00 an oz depending on where you get it, a recharge, [vac, leak test and charge[ will be around $100.
Your $40 cans of Freeze 12 are 12oz so you would need 3 cans, [$120 worth] assuming none of it leaks out. 94

 

Theoretically speaking, yes. However, in a practical application with a R12 designed system (smaller condenser, etc.), real world cooling performance does not match. I don't know of a single person who has converted from R12 to R134A and is happy with the cooling performance. Another reason not to use 134A would be the higher discharge pressures. If you have an old R12 compressor it may have a shorter life.

Again, I don't disagree technically, but real world performance says otherwise.

 

I have done more then a few retrofits ,[Airwolfe Auto Air Conditioning] over the last 10 years and I have yet to have a customer that was no satisfied with the result, that includes customers that were told by other shops in town about the "lower output"

Of all the retrofitted systems that did not work properly that came to our shop, most where because the retrofit was not done properly and once we redid them customer was happy, some of them had other problems, bad compressors, expansion valves, clogged, evap. or condensers, or not replacing pressure switch with an adjustable one, but then again they where improper retrofits because defective parts where left in place.

Again there is no reason you can not get a retrofitted system to work as well as the older R12 system or close enough not to matter. 94

 

Where do I get an adjustable pressure switch and how is it supposed to be adjusted?

 

Most auto parts stores will have them.

Between the terminals there is a set screw to adjust pressure, sold as retrofit pressure switch. 94

 

It is simply a fact that the R-12 system evaporator and condenser were not designed for R-134. The evaporator is too small to work as well with R-134. I get 34-degree center-vent temps at 94 degree outside temp and 72% humidity, here in Texas, with my R-12 charged1991 EF. I get 43-degree center vent temps in the same conditions, with my 1988 EF, which is converted, and has the same low and high pressures on my manifold set.

That being said, I prefer the R-12, but the R-134 works sufficiently.

Anyway, to the original poster, you are probably low on freon due to a leak. You obviously don't have the tools to get it running right, so pay the money and take it to a mechanic to fix it for you. A/C is worth the money. Not having it really sucks.

 

going from 110 to 48 degrees is a 62 degree drop. that is a pretty damn good.

anyway what are you pressures on high and low side? I have found that living in the Houston area between the humidity and heat that the ac system in an ef is just not designed to keep things that cool when its 90+ degrees and high humidity. I have done r134a, r12 and the duracool stuff. r12 was the best all around, it was cool at idle and got really frosty on the highway. the duracool is nearly as good at freeway speeds, but at lower speeds, like idle, it just doesnt really do so well. r134a is better than not having ac. vent temps at 100 degrees and 70% humidity roughly 40 degrees with r12, 43-44 with duracool, 48 with r134a...this was all at idle.