Air conditioning compressor coil replacement-mk4 vw

Apr 15, 2014
Air conditioning compressor coil replacement-mk4 vw
  • How to replace the AC compressor coil on a mk4 VW Jetta or Golf

    difficulty: 2/5

    related link: 1000q: AC compressor removal

    This writeup combines notes from zzi2u and pics and notes from almir about replacing their bad AC compressor coil. For support on this writeup, please post a followup comment in this thread in the forum or this one for ac coil replacement. The coil is an electromagnet so in theory, the wires can be reversed if they are accidentally reversed.

    Rich T's notes:

    Status update
    1- removed R/H front tire assy
    2- removed wheel well cover
    3- removed ~2 lbs of dirt stuck between the cover and the rear area of wheel well
    4- removed R/H side cover (belly pan already off)
    5- disconnect the turbo intake to gain better access to pulley
    6- remove serpentine belt.
    7- While holding the belt tensioner pulley back I loosened the top Compressor mount bolt using 3/8 air ratchet.
    8- removed bottom Compressor mount bolt using 3/8 air ratchet.(stays with compressor until you complete step 9)
    9- With a long pry bar dis-engaged compressor from mount point.
    10- using 3/8 air ratchet undo pulley nut and removed front clutch plate.
    ****Caution, be aware of the spacer that the clutch plate sits against this sets up the running gap between the clutch plate and the pulley**** (looks like a washer and sits on the shaft behind clutch plate)
    11- removed the retaining-clip ring for the Pulley.(see POC #4)

    *Next step I Tried a few different things but to save you time just used the following process or your on version*

    13- Using a very small metal hammer with a 1" square 12" long teflon drift. Tap the backside of the pulley towards the left hand side of the car, then rotated the pulley ~ 180deg then repeat, continued the process until you are able to remove the pulley by hand.
    14- Fight with the Clutch coil retaining retaining clip (remove), then remove clutch coil.
    15- If needed transfer the electrical connector to new coil. and pre-pair for re-assembly.
    16- Get a heavy reworking flat stone and remove any raised material on the clutch plate and the pulley where they come in contact with each other. (re-dress)

    Points of Caution (POC)
    1- minimize force on AC hoses
    2- Don't forget the clutch plate spacer
    3- remove retaining clip holding pulley before trying to remove
    4- remove retaining clip holding clutch coil before trying to remove,
    (used a pair of retaining clip pliers similar to snap-on Stock#: SRPC4700) 45deg
    the angle on the pliers is a pain but allow you to access the clip holes from under the car.
    5- try to avoid any metal to metal contact when removing pulley as the material is soft.(ref step 13)

    The final chapter
    On the rebuild an extra set of hands goes a long way.
    17- place the new clutch coil at the correct radial angle to allow installation of the wire clamp to the compressor housing
    be sure to align the anti-rotation lugs on the back with the compressor
    18- Have a variety of Retaining ring pliers (preferably with a very long nose and angled tips. I was never able to install the ring all the way with the pliers. I had to engage the ring as much as possible then complete the install by pushing the ring with a large screw driver to the final position. ** ensure ring is all the way home **
    *** Important**** install the clutch plate spacer on the shaft now as this can be difficult after the pulley is on ***
    19- coat the inner diameter of the pulley bearing with lubricant (thin) then install by hand.
    20- Install retaining ring clip same as item 18 *(little easier)*
    **If spacer was not installed after item 18 then follow this instruction.**
    21- Because of horizontal installation: apply some sticky grease or compatible substance to the back of the clutch plate seat face, place the spacer on the grease and centralize with the spline diameter. Take note of the master spline orientation on both the compressor shaft and the clutch plate to simplify the install. Offer up the clutch plate carefully to the shaft as to not move the spacer. Once installed ensure there is enough threads for the retaining nut to confirm that the spacer did not get caught up on the fit diameter during the clutch plate install. If seated correctly install the nut and torque as tight as you can (air ratchet helps). If not seated try again.
    22- Install electrical wire clamp to compressor body.
    23- Engage the electrical connector and install on the mount clip of the compressor.
    24- With the top bolt started in the compressor mounting hole. Position the compressor for installation starting with the bottom bolt. Once aligned start bolt thread finger tight, then pivot compressor moving the top bolt to align the installation. Start threads by hand on the top bolt. Apply final torque of both using sockets…
    25- Using a large pry bar going from the top (two person process) jam the lugs on the clutch plate. At the same time from the bottom torque the 14mm retaining nut. Caution don't let the top person drop the LARGE pry bar on your head.
    26- Install serpentine belt then release tensioner
    27- Start engine remain at idle and check the function of the A/C system.
    ** ensure all is clear in the engine area before starting **
    28- Assuming A/C is working (or your just fed up). Shut off engine then install items 1 through 5.

    Again Thanks to everyone and hope this saves someone some time and $$.
    **Stay Cool**

    Caution I tried to be as detailed as possible but might have forgotten some items.
    Please be sure to use caution when doing this of any other work and remember safety first.
    **Also use this process at your own risk.** PS great pricing on the clutch coil I paid $170.00. (not OEM)

    alimr's notes and pictures (click to enlarge thumbnails)

    My symptoms were:

    after rubber burning smell AC comp stopped working.

    Measured resistance of AC clutch coil -> Open
    Measured voltage going to AC comp -> 4.5V
    Large fan didn't work with AC ON, only small fan worked at low speed.
    With AC ON, ignition ON, engine OFF, fan set to 1, both fans must work at low speed, mine didn't.
    Measure voltage going to the big fan and both red wires (red/white) and (red/black) were giving voltage at the same time. One was 12V and the other 7V so that the fan didn't know at what speed to spin. After cutting one of the red wires with 12V fan worked.

    ac-1.jpg ac-2.jpg ac-3.jpg ac-4.jpg ac-5.jpg ac-6.jpg ac-7.jpg ac-8.jpg ac-9.jpg ac-10.jpg

    take a note of the belt routing before starting this procedure (see 1000q: AC compressor removal for pictures)

    1. use 15mm open end wrench or anything similar to pull serpentine belt tensioner towards the front of car, this will release the tension of the belt and have a nail ready so that you can push the nail through the both openings and lock tensioner in released position.
    2. remove 3 x 13mm tensioner bolts to to take out belt tensioner (very easy)
    3. remove 2 x 13mm alternator mount bolts, remove the plastic cap that is protecting main alternator to battery (thick black) wire to be able to see 1 x 13mm nut, remove that nut.
    4. now you can use pry-bar to separate alternator away from the engine
    5. in picture #1 you can see two long bolts that hold AC compressor, you can use 16mm deep socket with 3/8 drive from the top to loosen top bolt and the same for the bottom bolt but from the bottom side. (you don't even have to remove the plastic side splash shield and the plastic cooler hose).
    6. you can now remove 2 x 16mm ac compressor bolts (yes you will have enough room).
    7. even with bolts removed ac compressor will be in its place stuck so you will have to use pry-bar again to separate it from the engine. This time have something handy like wire or something that you can tie the compressor in the clutch up position like I did on picture #2 WARNING DO NOT DISCONNECT ANY AC LINES, ALSO BE CAREFUL WHEN YOU PULL THE COMPRESSOR UP SO THAT YOU DON'T BREAK THE PLASTIC COOLANT HOSE PIPE NEAR THE ENGINE BLOCK OR DAMAGE COOLANT HOSE.
    8. now everything is easy, spray some pb blaster or wd40 on the center bolt and remove the center 15mm bolt while using channel locks to hold the 3 little circles from the clutch like I did on picture 3
    9. bolt was easy to remove, and now you can simply lift the clutch up and remove it like I did on picture 4 (be careful not to loose thin shim that will be stuck to the other side of the clutch
    10. once the clutch is removed you will be able to see the pulley side of the clutch mechanism, you will also see snap-ring inside see picture #6 (this one was easy)
    11. as I said this snap ring was easy to remove, now you will have to use pry-bar or bigger flat head please see my note on picture #4 where arrow show you will use one of the bolts as a leverage point to pry under the pulley and lift up (surprisingly pulley lifted up without any problems).
    12. once pulley is out, you will see the clutch coil, (you will see it as on the last picture of the part one - but this was my new coil installed)
    13. WARNING in order to remove the coil you will have to fight for some time with this bigger snap ring, my pliers did not open wide enough so I finally decided to use the help of smaller flat head screwdriver ( I knew it was dangerous, I had protective glasses and this spring literally jumped into my forehead and bounced of in the direction of the coolant reservoir. So be careful please!
    14. once you remove your coil, you will see same as I did on picture #11 of the first part.
    15. save your old connector from the old coil since new coils will not come with connector, see pictures 7 and 8.
    16. on picture #9 you will see small arrow showing this little guide pin on the clutch coil, you will have to put this guide pin into the little dent shown with an arrow on picture #11
    17. make sure that during your installation of the dangerous snap ring the coil does not jump out of its locking place.
    18. again shorter fight with installation of the snap ring (since mine was bending and wasn't going on straight I had to use smaller screwdriver to keep pressure on the opposite end of the ring to so it does not slide up as I push the other end down.
    19. install pulley and its snap ring
    20. see picture #4 of the second par, note that there are splines and flat spot on the shaft, the same is on the clutch (see picture #3 and #4 of the second part) so make sure they click in with each other. (don't forget the shim under the clutch)
    21. again repeat the same step from picture #3 of the first part to tighten the center bolt and you are done.
    22. install compressor back to its place (put some grease on the mounting area so that the compressor slides in easier
    23. install alternator (this would be good opportunity to check alt. pulley vs alt fan operation)
    24 install serpentine belt tensioner
    25. don't forget belt
    ac-11.jpg ac-12.jpg ac-13.jpg ac-14.jpg ac-15.jpg ac-16.jpg ac-17.jpg ac-18.jpg
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