AC Conversion Kits - Toyota Nation Forum : Toyota Car and Truck Forums

Deadly Sushi · 05-23-2009, 06:08 PM

R-12 to R-134a....
Has anyone used these kits before? I dont have a lot of money and this would be a God-send if the thing works. Currently there is no pressure in the system. Nothing.
Help me out folks. I have to drive in rush hour in 90+ heat right now and the damn passenger front window wont roll down.

SamKT · 05-23-2009, 08:50 PM

There are both sides of the story. Some successful, some just costly failure.

Generally the closer the car was to the R12/134a change over date the more success you'll have in terms of system compatiblity.

skuttduck · 05-24-2009, 07:22 AM

I have not used the kit, but my Uncle has. He told me, as well as the service men working on our building air conditioning is you need to get the old R12 oil out of the system. If you don't that stuff turns to sludge.

I'm not sure how exactly you get the oil out, but that should be explained in the kit.

Mike Gerber · 05-24-2009, 09:03 AM

Quote:

Originally Posted by skuttduck

I have not used the kit, but my Uncle has. He told me, as well as the service men working on our building air conditioning is you need to get the old R12 oil out of the system. If you don't that stuff turns to sludge.

I'm not sure how exactly you get the oil out, but that should be explained in the kit.

You hook a vacuum pump up to the system and evacuate the entire system. This is something that might be best left to a pro. If you want to do this yourself, try going to a shop and just asking them to evacuate the A/C system for you. Then you can do the installation yourself.

Mike

Stillrunning · 05-24-2009, 10:44 AM

Evacuating the system does not remove oil from the system it is meant to remove water and air. Usually the kits have a chemical adapter to convert the oil. SamKT is right, some work some don't. 134a in an R12 system will not perform as well as the R12 as 134a systems need to be more robust, add to that any weaknesses in an old system and you will be disappointed with the cold air. First you need to fix the leak that caused the system to fail, then try to determine if any oil needs to be replenished - not an easy thing to do. I have done 2 134a conversions and was not happy with either. My last conversion I used a product called Enviro-Safe which is compatable with all oils and seals, they even sell an oil that will mix with all other oils - I am very happy with the results. Trying to do this yourself without proper equipment and NO knowledge or experience is not recommended and will, in the end, not save you money. I purchased gauges and a vacuum pump to do the conversion as the price of vacuum pumps has come way down, but only because I plan on doing all my own A/C work.

Deadly Sushi · 05-24-2009, 12:06 PM

well there currently is NO pressure in the system.
Where is the oil in the system kept?

Stillrunning · 05-24-2009, 03:55 PM

Quote:

Originally Posted by Deadly Sushi

Where is the oil in the system kept?

Everywhere, some in each component. You'll need a manual to know the total volume and if a component is replaced how much to add to that component. The critcal part needing oil is the compressor. If it only leaked down once and you have not refilled a number of times then you won't need much, if any, maybe 1/2 an oz. Look for black buildup at the compressor shaft and pressure lines, that may be a clue where the leak is. Best way would be to charge and use sniffer (which you won't have) or even soap and water to look for bubbles. If the evaportaor or condenser is leaking it'll be expensive. Compressor shaft seal can be replaced.

MyFreeCamry · 05-25-2009, 11:43 AM

To correctly go from R-12 TO R-134a you must:
1 - Evac entire A/C System
2 - Flush entire A/C system
3 - Replace Reciever/Dryer and Pressure switch
4- Replace all O-rings with R134a O-rings
5 - Replace High and Low side adapters
6 - Fill system with R-134a and oil.

flyeri · 05-25-2009, 07:03 PM

Quote:

To correctly go from R-12 TO R-134a you must:
1 - Evac entire A/C System
2 - Flush entire A/C system
3 - Replace Reciever/Dryer and Pressure switch
4- Replace all O-rings with R134a O-rings
5 - Replace High and Low side adapters
6 - Fill system with R-134a and oil.

Correct and not really a great job for DIY. The evac, flush, and fill portions should be left to someone who knows what they are doing.

Strum · 05-25-2009, 07:17 PM

Anyone have an idea of the cost for conversion when done by a pro? I purchased my car about seven years ago and it has sat for the past three. I started it up today and there is no cold air. The compressor doesn't engage, but I am assuming that is because the system is low or empty.

Is it illegal to have someone charge the air with R12? If not, is converting worth it?

Deadly Sushi · 05-26-2009, 10:58 AM

Alright.... so there is NO pressure BUT there is STILL oil in there?

So you think a can of stop-leak, then two cans of JUST 134a (no oil) would be the way to go? OR......
One can of stop-leak, a can of 134a WITH oil and then a can of JUST 134a?

Which you think is a better way to go?

I dont have money for new parts. I was laid off months ago. ANNNNND the damn window motors died in two of the windows

hill8570 · 05-26-2009, 11:35 AM

Quote:

Originally Posted by Strum

Anyone have an idea of the cost for conversion when done by a pro? I purchased my car about seven years ago and it has sat for the past three. I started it up today and there is no cold air. The compressor doesn't engage, but I am assuming that is because the system is low or empty.

Is it illegal to have someone charge the air with R12? If not, is converting worth it?

How do you know there's no pressure? I'm under the impression you don't have manifold gauges...

OK, let's assume for a sec the system actually is discharged. That means the system has been sitting for an unknown amount of time with atmospheric air (and humidity) in the lines. To fix this, a tech is going to have to replace the receiver / dryer (since you can bet the dessicant is saturated), draw down the system with a vacuum pump, keep vacuum applied while humidity, etc. boils off, and then monitor the pressure in the system to see if she holds vacuum. Probably won't -- some of the seals have probably dried out. So, the tech has to track down the leaks and fix them. After the system holds vacuum, then he will charge up the system with R-12. If these steps aren't followed, then you can bet that either all that nice expensive R-12 will leak out, your system will freeze up from the moisture, or both.

Now, to do a proper retrofit, all of the above steps need to be done, PLUS first flushing the mineral oil out of the system before adding the R-134 compatible oil, replacing all of the seals with seals compatible with R-134 (may not be necessary...Toyota may've used seals compatible with either in their 90's models), and replacing the R-12 fittings with fittings compatible with R-134 equipment. That's a lot of extra labor. Better to just get your system fixed and recharged with R-12.

Deadly Sushi · 05-26-2009, 12:05 PM

You have a great point there!

Hmmmmm... Im going to rent a vaccum pump from Auto Zone and evacuate the system

THEN Im going to check for leaks. THEN Im going to recharge the system!

MyFreeCamry · 05-26-2009, 12:12 PM

Hill, same thing I listed above. I have a 92 camry that came with R12 from the plant. Two years ago, the R12 leaked out, I simply recharged with R134a and let it go. A/C still works.

Deadly, one issue, R12 is technically no longer allowed for use due to its enviromental hazard. You have to use an R12 recovery machine to properly recover the R12 and then dispose of it properly. Good luck finding R12, and if you do, make sure you are sittin down for the price.

Here is what I can suggest for you to do:
Cheapest: Go to autozone or some place like that and pick up a couple cans of R134a (don't worry about with oil, you don't know how much is left in your system and the system takes a certain amount of oil), and the high and low side adapters. Find a buddy with a set of manifold gauges and knows what the hell he is doing (I know a guy that tried to recharge his sytem only to put the can on the high side, stick the can between his legs, open the valve, and next thing you know the can exploded and literally froze his nuts off.) and have him recharge the system. If it works for a while great, you aren't out that much money, and you can then recharge it again just by adding some R134A.
Correctly: Take it to a shop and have them completely evac the system and flush it. You replace the o-rings, receiver/dryer, and the high and low side adapters. Then return to a shop and have them recharge the system with r134a. That would be the cheapest way to do it.

hill8570 · 05-26-2009, 12:30 PM

Quote:

Originally Posted by Deadly Sushi

You have a great point there!

Hmmmmm... Im going to rent a vaccum pump from Auto Zone and evacuate the system

THEN Im going to check for leaks. THEN Im going to recharge the system!

Not sure how much rental is on a vacuum pump, but Harbour Freight has a decent one ( http://www.harborfreight.com/cpi/cta...emnumber=98076 ) for $80. Not fast, but it gets the job done.

They also sell a decent manifold gauge ( http://www.harborfreight.com/cpi/cta...emnumber=92649 ) for $40. Only has fittings for R-134, 'tho.