|Air Conditioning Retrofit - R-12 to R-134a|
|So it's summer time and you're sick and tired of enjoying the twisties in a very hot car? Arriving somewhere important dripping wet? Getting your air conditioning working again may be easier and less expensive than you ever expected! If your a/c compressor still works, you can get your a/c working again for less than $100!|
Know what you are doing before attempting this procedure. It is not difficult, but
you could probably kill yourself if you tried. This procedure assumes that your a/c system
has completely leaked all of the R-12 freon. Always charge through the "low
side" (the larger hose). Charging through the "high side" could
result in explosion of the freon can. If you are not confident in your abilities, take the
car to a professional. You could damage expensive components if you are not careful.
DISCLAIMER: While researching this project, it was discovered that opinions vary widely regarding the use of R-12 and R-134a freon. Generally, the "experts" said not to use R-134a because it is not as efficient, and will not work well in a system designed for R-12. One idiot.. er... "expert" even argued over a 5 degree difference! Many "experts" said the R-134a would destroy seals designed for R-12. And the "non-experts"... they seem happy with their conversion! Do your own research and form your own opinion.
Get an R-134a retrofit kit and receiver/drier from your local autoparts store, and a few o-rings from your local VW dealer.
retrofit kit made by Interdynamics
|You will also need to pull a vacuum on the a/c system. Harbor Freight sells an "air vacuum pump" (less than $20.00) that is used in conjunction with an air compressor (free - use a friends!). You will also need a hose and R-12 fitting to attach the vacuum pump to the a/c hoses. We borrowed the hose and fittings (free!), so we still need to locate a "normal" source (Harbor Freight maybe?).|
|* Harbor Freight Item 3952-5VGA - The original version
as used here.
* Harbor Freight Item 92475-1VGA - Newer version that has a R143A Connector
O-rings to be purchased from VW Dealer ($0.15 each):
803-260-749 Quantity: 4
803-260-749-A Quantity: 2
803-260-749-B Quantity: 1
These were not specifically R-134a o-rings. If you can get o-rings that claim to be R-134a compatible, it might be a good idea. Otherwise, don't worry about it!
Basic tools are needed:
1. 17mm wrench
2. 19mm wrench
3. 22mm wrench
4. Adjustable wrench
5. 10mm socket
6. Flat head screwdriver
7. Brake cleaner
|Replacing O-Rings / Receive/Drier|
|While it may not be completely
required, it is highly recommended to replace at least the o-rings on the fittings in the
engine compartment. Clean all fittings (before disassembly) with brake cleaner.
Clean fittings will allow easy inspection for leaks after retrofit. The o-rings to be
1. Two fittings on condenser (in front of radiator)
2. Two fittings on A/C compressor
3. Two fittings on receiver/drier
|Make sure the old o-rings are removed before re-installing fitting!|
|Top fitting on condenser|
|Bottom fitting on condenser|
|The receiver/drier is located under windshield washer fluid bottle.|
|To remove the old
1. Disconnect upper condenser hose
2. Disconnect lower condenser hose
3. Disconnect hose on receiver/drier located towards back of car
4. Remove two 10mm bolts attaching bracket to frame
5. Remove receiver/drier and "hose" as one unit.
|This is the old receiver/drier with "hose" still attached. Make note of where the bracket attaches so you can installed it on the new receiver/drier in the same location.|
|The new receiver drier has been installed with the "hose" partially tightened. Be sure to install new o-rings on both fittings that attached to the receiver/drier. Competely tighten the fitting once installed in the car.|
|Replace the o-rings on the two fittings on the a/c compresser.|
Note: If you want to take this repair/retrofit one step further, you could remove the a/c compressor, and drain and replace the R-12 oil with R-134a oil. We did not do this.
|Pulling a vacuum|
|The purpose of "pulling a vacuum" is to remove air and moisture from the system. Lowering the atmospheric pressure causes water to boil at lower temperatures. Moisture can cause damage to the system, and result in reduced cooling efficiency.|
|A vacuum was pulled for about 35 minutes on the low side...|
|and another 35 minutes on the high side.|
|If your a/c system has been open a long time and/or exposed to high humidity, you may want to pull a vacuum for a longer period of time. You want to make sure that all air and moisture are evacuated from the system.|
|Charging the system|
charging the system, read and re-read the directions included with your kit. Too
much knowledge is a good thing!
|Install the new R-134a adaptor on low side. It simply screws on. The Interdynamics kit only included one adaptor that fit on the factory fittings. Since you only charge through the low side, I see no reason (besides "legal" requirements) you would install an adaptor on the high side.|
|To charge the system, start the car and turn the a/c on high. Attach hose to the low side, and fill the system with two cans (12oz each) in an upside-down position.|
|Next, fill with the Oil Charge.
The Interdynamics kit included an 8-1/2 oz can. The VW Technical Bulletin for
retrofitting R-12 to R-134a (info to be added) calls for 5.8 oz total system oil capacity
when using the Sanden SD 508 compressor. Do not use the entire Oil Charge or you may
overfill the system. Overfilling may cause compressor damage and decrease cooling
Remember, there is oil already in the system unless you took the time to remove it all. We used about 6 oz.
|Check your pressure with the included gauge. If additional R-134a freon is required, fill with the can in an upright position.|
|Install the dust cap.|
|The high and low
side fittings were the same. You will only need to purchase one R-12 adaptor to use
when pulling the vacuum.
The water temperature is higher with the a/c running. Watch your water temperature gauge to ensure you do not overheat in stop and go traffic.
Remember, the Interdymanics R-134a Retrofit Kit is designed
to be idiot proof. If you find yourself questioning too much, re-read the directions and
remember they made the kit so even stupid people could use it!
The A/C compressor was dead and replaced with a used compressor that was purchased three years ago for $45.00. Not bad.. only three years after buying the compressor, and one year after actually installing it, the A/C works again!
|Money well spent!
Having working a/c during the summer is great!
Only time will tell on the true success of this retrofit, but for the cost, there is no reason to arrive at work dripping in sweat!
Temperature readings were taken to see how well the R-134a retrofit cooled. A baseline was established by placing a thermometer in the center vent and allowing the vent to run on high for about 5 minutes. The A/C was turned on high and allowed to run for 15 minutes. All testing was done while driving (mostly stop and go, not highway).
A/C retrofit/repair occured on June 8, 2003
June 12, 2003:
June 13, 2003:
June 18, 2003:
Futher testing will continue for leak detection and to insure proper long-term operation.
August 21, 2003:
August 10, 2007:
AirCondition.com Bulletin Board
IrocZone.com A/C Repair/Retrofit
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