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VW MKIV-A4 TDIs (VE and PD) This is a general discussion about A4/MkIV Jetta (99.5-~2005), Golf(99.5-2006), and New Beetle(98-2006). Both VE and PD engines are covered here.

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Old July 24th, 2006, 10:21   #1
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Join Date: Oct 1999
Location: columbus, ohio usa
Arrow How To Replace Compressor & Recharge System - AC Pics!

After searching the forums for a post on how to repair my air conditioning, I really didn't find anything in detail, so I just jumped in and did it myself. I have a 1999.5 Jetta with manual trans. The whole process took me about 5 hours, including a couple mistakes. By reading this post you can probably do it in about 3 hours with no complications. The symptoms I was having initially were poor cooling (compressor was engaged), then severe noise like a bucket of bolts, and eventually total loss of function, after a couple more days. The a/c button on the dash was lighting up, but there was no voltage at the wiring harness. There was little charge left in the system. I diagnosed this as compressor failure and a leak at the shaft seal, after inspecting all the hoses and the condenser in front of the radiator.

I ordered the following parts from Impex: AC Expansion Valve COST: $35.71 2. AC Receiver Drier COST: $69.97 3. AC Compressor
COST: $300.00. I'm not sure the expansion valve was bad, but I didn't want to take any chances of having to order more parts. In doing this job, I discovered that the receiver-drier is supposed to be replaced every 3 years, even if the system seems to be working OK. The receiver drier removes impurities and moisture and must be replaced whenever the system is open.

Next, I ordered 6 cans Enviro-Safe Industrial 12a for $45.00 from autorefrigerants.com. It turns out I only needed 2 cans to do this job, about 10 ozs., which is the equivalent of 32 ozs or R-134. The system calls for 750 g or 26.8 ozs. R-134a, The enviro-safe is a hydrocarbon, not chloro-or fluorocarbon. I purchased O-rings for the system, oil charge with R-134, and a gauge/connector at Advance Auto Parts for about $20.00 for all.

Now, on to the job. You will need the following tools: 17mm socket, phillips screwdriver, pry bar, adjustable crescent wrench, 4, 5, and 6mm hex keys, possibly wire cutters, solder and heat shrink tubing. If there is charge in the system, the environment will thank you if you take it to a shop to have the refrigerant recovered. Mine had already leaked out.

First, put the car up on jack stands in the front and remove the passenger side wheel, skid plate, and side skirt. You will see the compressor right at the bottom of the front of the engine:

Remove the serpentine belt by using a crescent wrench on the tensioner and just slip the belt off. Put it up out of the way and try not to let it come of the other pulleys.

Next, if there is charge in the system, make sure it's evacuated and then use the 6mm hex key to remove the refrigerant lines from the rear:

Place the hoses down on the ground so that any contaminated oil can drip out. I placed a wrench on them to hold them down. There was some oil, but not too much. You may see pieces of slivered metal in the oil. I also ran a bit of the new refrigerant through the suction port to flush out at least that line. If you use the enviro-safe refrigerant, you don't have to feel guilty about this.

Next, remove the electrical connector and use the 17mm socket to loosen the 2 bolts holding the compressor on (11:00 and 2:00):

Mine was in very tight and took some prying to get out, even after the bolts were removed. Just make sure not to drop it on your head. Save the bolts to re-use.

Next, remove the receiver-drier. This is located on the passenger side of the radiator. Mine was labeled "Parker" and "Made in USA!"

In order to remove it easily, remove the screw holding the refrigerant line on top of where you will be working:

Next, gently move the refrigerant line from which you just removed the screw. It's flexible enough to move without breaking if you are careful. Then use the 6mm hex key to remove the refrigerant line from the top of the receiver drier, seen in pic above. Get under the car and use the 6mm hex to remove the refrigerant line from the bottom. The top line was on very tight and connects to the condensor, so be very careful not to break it. Finally, use the 5 mm hex key to remove the hex bolt retaining the receiver-drier. You can then slip 1/2 of the holder out of a slot toward the front of the car.

Install the new receiver in the openingsame as the one you removed. The receiver/dryer goes in welded side up, at least in the replacement units...just check as the bottom line has three holes needed and the top just two:

slide the holder back together and reinstall the 5mm hex nut, but do not fully tighten yet. Remove the old o-rings from the refrigerant lines and replace with the appropriate size. Slide the receiver-drier up in the holder and align the opening with the connection to the condenser, then reinstall the 6mm hex nut into the top thread. Once it starts getting hard to turn, go ahead and fully tighten the retaining band with the 5mm hex, after you make sure it's up high enough in the slot. This will prevent you from torquing (and breaking) the condenser. The 6mm hex must be fully tightened so there is no gap between the refrigerant line and the top of the receiver. Next, reinstall the bottom refrigerant line after you replace the o-ring. You are ready to install the new compressor.

Locate the 17mm bolts and install the new compressor using them.

Reinstall the belt making sure it's on all the pulleys correctly. Next remove the factory plugs seen in the pic above using the 6mm hex. Replace the o-rings on the refrigerant lines and then install to the back of the compressor. Make sure there is a nice tight fit to the machined metal surface. In my car, the plug was a different style, an so I had to reuse the connector from the old compressor. If you have to do this, I recommend soldering the wires and then using heat shrink tubing:

It should look like this when you are done:

Slide the wire harness into its metal holder and then connect it.

Next, you may replace the expansion valve. It is located on the firewall in front of the passenger seat, and covered with a plastic insulator. The insulator unsnaps from the passenger side and has a hinge on the driver side. Here is a pic with the insulator already removed:

Using the 5mm hex, remove the first bolt holding the aluminum retaining clip seen in the pic above. Carefully slide the hoses out of the valve and replace the o-rings.

Use the 4mm hex to remove the other two hex nuts and then slide the valve off. Replace the o-rings. Here is the old and the new valve with the 4mm hex bolts:

Reinstall the new valve using the 4mm hexes first, then reinstall the aluminum retaining clip and the refrigerant lines. Replace the insulator. It only fits one way. Now, you are ready to test the system. Follow the directions with your gauge and install it to a can of oil charge. With the car off, snap the quick-connect onto the low side refrigerant line, located right near the receiver-drier. It has a black cap on it:

Open the valve on the can and let a little refrigerant into the system, then close the valve on the can. Note the pressure reading and wait 5 minutes. Make sure the pressure doesn't drop, although it may go up. If it goes down, you have a leak. Luckily, I did not. If there are no leaks, allow the oil charge into the system by turning the can upside-down. Now, get another can of refrigerant, pierce the top, and install to the lowside connector. Start the car and turn on the AC.

Open the can of ec-12a refrigerant and allow it into the system, slowly. Turn the can upside down, but not all at once - a little bit at a time. It will take the whole can. Check your pressure. Mine was about 35 psi.

It will probably take about another 3-4 ozs from a second can. DO NOT use the whole second can. It is too much.

Get inside the car and check your temp at the outlet on recirc mode. It should look like this:

Sweet! Now I have a/c again. And, it's colder than before using the EC-12a refrigerant. Good Luck.

Last edited by wolfman; December 17th, 2014 at 05:58. Reason: images are no longer on my server; looking for them
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Old July 24th, 2006, 18:50   #2
Join Date: Apr 2003
Location: Stafford Virginia 22556

Nice write up. I am not flaming you, but because you didnt draw the system down, you have a small amount of moisture in it which will shorten the effective lifespan of the drier. Also... you may have a problem in the future if you take your car to any shop for a/c repair. Once they put a refrigerant identifier on it, they'll probably show you to the door. Basically, recovered r134a goes in this can, recovered r12 goes in that can, and since we only have 2 cans in the machine, bye bye. Contamination by strange refrigerants costs hundreds of dollars in filters that need to be replaced. So... we just don't work on anything but pure r134a or r12 systems. A pawn shop would have a cheap set of gauges for $50 or so, even Yellow Jacket sells a cheap set for that amount. You should check to see if your high side sensors are working as well, i.e. high pressure/overheat cut off, high pressure high speed fan turn on, etc. It's hard to beat that 32 degree reading however you got there.
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Old July 25th, 2006, 06:26   #3
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Great write up and pictures! Good point about not pulling a vacuum. You may want to discharge and refill the system a couple of times with the extra refrigerant you bought to dilute the air and any moisture in the system.

2004 Jetta GLS TDI 5M Plat. Grey w/ Leather. RC Stage 2, G60/VR-6 clutch, steel skid plate, TDIHeater, CAT 2um fuel flter, Phat Noise, and VDO boost & volt guages.
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Old July 25th, 2006, 07:53   #4
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Thanks for the info. Is there really enough moisture in there to worry about? I thought the drier would remove that. I guess I have the cans - it wouldn't hurt to drain and refill.
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Old July 25th, 2006, 09:21   #5
Join Date: Apr 2003
Location: Stafford Virginia 22556

The principal purpose of drawing a vacuum is to lower the atmospheric pressure inside the system. Doing that "boils" water and eliminates it completely. The secondary purpose is to check system integrity. On really humid days like we've had lately, a good deal of moisture does get in there.... is it enough to damage something .. I'm not sure. I just go by how I was trained. It's sort of like trying to get the horse back in the barn now... I'd leave well enough alone and enjoy the 32 degrees.
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Old July 25th, 2006, 20:14   #6
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Location: Wilmington, NC
Fuel Economy: 36 mix

HC-12a does not need to be perfectly dry. In fact, you do not need to replace the drier in the system. Also, you can mix R-134a with HC-12a but its technically illegal to mix refrigerants. If you do have R-134a then you don't want water in the system though.
Let's review.
moisture + HC-12a = who gives a crap
moisture + R-134a = acid

Draw the system down to a vacuum to remove the R-134a, then release the vacuum and let air into the system. Then fill up HC-12a. No drier change necessary.

Otherwise... Wolfman, thanks for the writeup. If I ever have a problem I'll know what to do

Post if thou noticest improved mileage with the HC-12a (expect only 1-2mpg though).
2002 Jetta Sedan ALH-01M: 2 um Cat FF, Wingnut-3 CCV filter, polyurethane fuel lines, 5 brake light mod, Ventectomy, Polysiloxane vacuum tubing, Pioneer DEH-3800MP w/ KFC-1389ie, Panzer Plate, EGT+Boost+Oil Temp Gauges, Boost Valve, KERMA Line Pressure Mod, LED Lighting, HC-12a refrigerant, Optima 75/35 AGM, .187 nozzles, Hawk HPS pads.
Coming Soon: ESP retrofit, Custom Greasecar.

Wish List: Tow Bar, DSG or CVT transmission, or even a 5 speed manual. To hit 42+ mpg

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Old August 4th, 2006, 12:40   #7
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vent temps are now down to 21 degrees F, after a couple weeks of use. I did purge the system to get out any moisture which may have been in there.
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Old August 4th, 2006, 14:25   #8
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I don't think that it's supposed to be that cold.
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Old August 4th, 2006, 21:02   #9
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Yea, 21F = frozen evaporator and some major damage. You might want to reduce your content by 1/2oz or so.
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Old September 13th, 2006, 05:07   #10
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Default How to Replace Compressor & Recharge System

I'm going through the same thing right now with one of my cars.
Impex: AC Expansion Valve COST: $35.71 2. AC Receiver Drier COST: $69.97 3. AC Compressor
COST: $300.00.
In looking at Impex, they have 3 drier's 3 expansion valves etc. How do I know which parts to order. Did you have any part numbers you could include? Does it make a difference? If I'm switching to ES 12a I probably don't want a expansion valve listed as R134 - correct?

Do I want a drier with or without a switch? I assume I don't need one with a switch if my AC was working before the compressor seized.

Do I need any special O-rings with ES 12 - I noticed you use different O-rings for R134 and R12. But ES 12 seems to be something completely different than R12.
2002 Jetta RC3, PP520, Black, for the wife
1998 Jetta RC2/RC3, Black, for the son
1997 Passat RC3, Black, for the daughter
We have our own Mini TDI club in our driveway.
1998 Jetta RC2/RC3, PP520, Black - who will get this one?? Everyone but me - Daughters use it for school...
1997 Passat Silver RC3, maybe this one's for me, were running out of drivers. - Went to #2 son.
1997 Passat Black RC3 - Went to #2 daughter.
2002 Jetta, Silver, T4's - Ahh Finally.. my own Jetta!!
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Old April 25th, 2008, 18:16   #11
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On the 98 Jetta follow the AC lines to the right front corner of the car.
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Old April 26th, 2008, 19:36   #12
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Default Web site

Want to be sure I order the AC parts from the correct web site. What is complete path to Impex?

Thank you,
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Old April 26th, 2008, 19:55   #13
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Location: Dayton, Ohio

Originally Posted by ugetwhat
Want to be sure I order the AC parts from the correct web site. What is complete path to Impex?

Thank you,
"When you have two competing trading theories which make exactly the same predictions, the one that is simpler is the better & more profitable one."
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Old April 27th, 2008, 19:56   #14
Join Date: Sep 2005
Location: alabama

can anyone point out how to check the nut onthe input shaft on the compressor? someone told me to check that before replacing my compressor to make sure it was tight enough.
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Old April 29th, 2008, 06:36   #15
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Location: ATHENS, GA
Fuel Economy: 40-50ish, haven't measured
Default Additions To Directions, Some Important And Helpful Notes

this edit pertains to an A4 ALH Golf TDI 2000
the receiver/dryer goes in welded side up (according to the one that I ordered, not down!)...different than thread states...
make sure to check as the bottom refrigerant line that attaches to your receiver/dryer has three holes needed and the top just two...
make note of the following links and see which is the tensioner for the serpentine belt from this diagram by mogolf....
also, DO THE JOB RIGHT THE FIRST TIME, much easier if you have a shop evacuate the system down with vacuum and then vacuum for a while before recharging...ENSURE NO MOISTURE IN SYSTEM
make sure you drain existing oil out of your new compressor by turning it by hand upside down...then replace with about 4.4 oz of new oil (should be supplied by whoever you ordered your compressor from)...oil goes into the suction side hole of your compressor, you can give it a turn until it begins to come out the discharge side if you like to make sure it is lubricated well before installing...also, a shop can inject oil with the freon to make sure there is enough in your system...
note on a new compressor...got my kit from www.discountacparts.com
cost was 365$ shipped for compressor, expansion valve, and receiver/dryer, with all new o-rings for the entire system and oil...shipping was prompt and via ups...
any questions feel free to email me or send a pm...best, Walter
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