Took my first trip to the beach this year and discovered the air conditioner is not fully functioning anymore. It worked great when the temperatures were still in the 70s, but by the time it hit the 80s and direct sunshine/traffic, the air temperature was just not very cool anymore. High temperatures and leather seats -- the results are not very pleasant.

Anyway I had the car recharged about three years ago so I'm kind of surprised I'm having a problem with it now. Before I go and spend who knows how much to see if I actually have a problem, what does everyone think about the little conversion kits that they sell at the local Autozones and Pep Boys?

Can they really work? Or would I need to remove and replace certain components to make it work properly? Even if the cooling efficiency is not as good as it was with R-12, I can see a huge cost savings by using the newer stuff.

Anyone try this and had any success with it?

Thanks!

 

First, have the system checked to make sure it's holding pressure. If it is, you may just need a top off of R-12. When you turn it on, does the air from the vent get cooler?

 

I used one on mine. I just the other day turned it on after sitting for awhile and it still works.

 

I had mine done by Eurosports last year. The only thing I'd recommend is that you replace the receiver/drier during the conversion.

 

My experience is, have a professional shop do the conversion. they have to tools
to evac the R12 and install the correct amount of esther oil for the R134. I have
done this to a few older VW's and without the machinery it is a iffy at best.

btw.. There is a R134 shortage this year as a plant exploded a few months back.
Just a fyi.

 

The major "snag" to doing a proper R-134 conversion is getting the system evacuated properly. Most A/C shops will charge you about $35.00, or what ever the going hourly labor rate is.

The second "snag" is removing ALL of the R-12 compressor oil. R-12 and R-134 oils are not compatible with each other. If you add R-134 PAG or Ester oil to a system that stilll has R-12 oil, you get a corrosive mixture that eats seals.

As far as using a "kit" goes, you can do it. AT A MINIMUM you need to replace the reciever/dryer and it's O-Rings. You can get new O-Rings at places like NAPA, Pep Boys, Auto Zone and the like.

I've converted two NAs to R-134 and both systems worked fine. I started by removing the reciever/dryer and compressor. I dumped the old oil and then used my air compressor to blow out the remaining plumbing.

Once the lines were clear I re-installed the compressor, installed the new reciever/dryer and O-Rings, new R-134 service fitting adapters, and then evacuated the system. Most shops will pull a vacuum and let the system sit for 30 minutes or so, but I prefer waiting at least an hour. This way I know I have a good vacuum and the system is not leaking. This also gives the system some additional time for trace amounts of refrigerant and moisture to vaporize. I pulll vacuum again just before I start to charge to insure that I have removed as much "junk" as possible from the system. While I'm pulling the second vacuum I disconnect the low pressure switch and jumper the wires. You need to do this because the compressor may not engage while you are adding the initial oil and refirgerant charge.

I start the recharge with a can of R-134 oil. To get all of the oil charged I run the A/C just long enough to empty the can. Once the initial oil is charged, I turn off the A/C, remove the oil can, and connect an R-134 can to my gage manifold. From here on it is just a matter of adding enough R-134 to give you a suction pressure around 30 psi, and a discharge pressure around 150 psi.

At this point you need to set the A/C controls to max cold, fan on high, and windows down. Charge the system in steps: Open the charging valve, add some R-134, and close the valve. If the suction pressure drops below 20 PSI, add more R-134. Once the suction pressure stays above 20 psi, check the discharge pressure, center vent temperature, and watch the reciever/dryer sight glass for bubbles. Add enough R-134 to get a 30 psi suction pressure, minumum bubbles in the sight glass, and a vent temperature between 45 and 50 degrees.

Once you get a low vent temperature and acceptable system pressures with no or minimum bubbles in the sight glass, close the car windows, turn the fan to a lower setting (I use '2') and let the system cool the passenger comparatment. As the system cools the car, you should see the suction pressure drop to the point where the compressor cycles on and off.

Once you get the compressor to cycle, shut the A/C and engine off. Close ALL valves on the gage manifold, and disconnect the hoses. Have a rag handy to catch any blow back, especially from the discharge side. Clean up any blow back and install new service fitting caps.

NOTE1: Manually increase the engine RPM to around 1200 or so while you are charging. You need to do this to get the suction pressure lower than the R-134 can pressure so the gas will flow from the can to the system.

NOTE2: To do a proper conversion you need a vacuum pump, A/C thermometer, and a set of R-134 gages inaddition to R-134 fitting adapters, R-134 service fitting caps, R-134 compressor oil, and two to three 12 oz. cans of R-134.

NOTE3: Charge to the LOW or SUCTION side ONLY! On early cars the low side fitting is hard to get to and you will not be able to install the correct R-134 service adapter. On later cars there may be two low side fittings. One is at compressor and the other may be near the driver side shock tower. One early cars the HIGH side fitting is at the reciever dryer, and on late cars the high side fitting is at the driver side shock tower.

NOTE4: When charging with a gage manifold, DO NOT OPEN THE RED VALVE at the manifold! Opening the RED valve will connect the compressor discharge to the charging port and you will over pressure the refrigerant can which may explode!

NOTE5: Later cars have TWO pressure switches at the reciever/dryer. The BLACK switch is the low pressure switch. The GREEN switch is a "High Refiegerant Temperature" or high discharge pressure switch. The black switch controls the compressor, and the green switch puts the radiator cooling fans on HIGH speed.

 

Damn Cliff, I wish I would have had this explanation when I converted my system a few weeks ago. Low pressure port on compressor and high on driver's shock tower?? That's just crazy! Wouldn't you want the low side where you can easily get to it? Threw me for a damn loop and pissed me off that I took ended up taking it to a shop.

 

If your system has been holding pressure for three years and has just leaked down enough to be considered low I would top it off with R12 or a compatable blend to get you by untill something else major goes bad (compressor) then do a 134 retro. Charlotte 944 has explained the correct method for doing a 134 retro. Unless you have bad hoses or hose connections the main places that leaks occur are the two schrader valves and the compressor seal. The compressor seal is most likely. It needs oil on it to create a good seal and in the winter when the system is not used much it will leak a bit over time, at any rate a leak that takes 3 years to leak down would be hard to find. Good luck.

 

Yeah, my first contact with Porsche A/C systems got me too. I was trying to add some R-12 to my old '84, and based on my previous A/C work I picked the fitting at the reciever/dryer.

Fortunately I realized that no R-12 was charging, and then I figured out that I was connected to the high side.

The real bummer is that to charge an early system you need to take the tension off of the A/C belt, swing the compressor down, connect you low side hose, and then CAREFULLY tension the A/C belt. If you go too far you can damage the fitting and/or the hose connection. Once you have the system charged you need to slack the tension, take the hose off, and then tension the belt. BIG PITA!!!!

When you get right down to it, if you don't know what is what, you are a lot better off having a professional do the work.

 

Probably the direction I'm leaning towards :-)

Thanks for all the information everyone. I thought perhaps the "kit" would be a simple, cheap fix for my problem but since dealing with an A/C is not exactly safe if done incorrectly, I think I will take it to a professional and have them attack the issue.

Hopefully the system is just leaking very slowly and I can get it back to where it's at least acceptable. The cost of R-12 however is outrageous!

 

Charlotte944........

A truly OUTSTANDING documentation of the R134 conversion procedure!

Thanks much!

 

How much do professionals usually charge to convert? My compressor may need some work too since I can hear it making a sort of dry rolling sound... probably the a/c clutch?