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Audi A4 1996-2001, S4 2000-2002 (B5) AC Evaporator replacement


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Last Post: Aug 13, 2013 4:51 PM Last Post By: Highfructosecor...
AndrewA4q96

Posts: 171
Registered: 01/23/04
AC Evaporator replacement
Posted: Aug 29, 2005 9:52 PM
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Attachment R134a.jpg (154.4 KB)
Large pool of bright green slimy oil under the car, emitting from the AC drain by the passenger side sub frame mount. I think this can only mean one thing, that the A/C evaporator has blown a leak. I had the AC recharged about a couple of months ago, and I know they used a fluorescent green leak detector die, so that explains the color. It can' t be coolant, as that is blue. No other sign of any leaks from anywhere under, in or around the engine bay, everything is dry and clean. The A/C suddenly failed in the car, one day worked perfectly, next the compressor will not engage (I am guessing due to lack of pressure in the system).

This all leads me to one conclusion, that the evaporator has failed. As the system is no longer charged, I can see no problem with removing / replacing parts, only question is what to replace.

Given the labor involved in reaching the evaporator, I want to perform as comprehensive a job as possible to avoid needing to revisit this area of dash any time soon!

I am planning on replacing the evaporator, heater core, restrictor tube, and any associated o-rings.

Should I replace the drier canister? Are there any other parts which should be replaced that I'm missing?

Thanks in advance!
corradoman

Posts: 107
Registered: 02/14/04
Re: AC Evaporator replacement
Posted: Aug 31, 2005 7:28 AM   in response to: AndrewA4q96 in response to: AndrewA4q96
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You will need to replace the reciever dryer. This repair can be done without the removal of the dash. Forgot to mention you will also need seals for your evaporator.
AndrewA4q96

Posts: 171
Registered: 01/23/04
Re: AC Evaporator replacement
Posted: Aug 31, 2005 10:14 AM   in response to: corradoman in response to: corradoman
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Thanks corradoman! Following good advice as per your suggestion I've purchased all new seals and dryer.
corradoman

Posts: 107
Registered: 02/14/04
Re: AC Evaporator replacement
Posted: Sep 1, 2005 3:39 AM   in response to: AndrewA4q96 in response to: AndrewA4q96
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Hi mate if you need any help with the repair dont hesitate, briefly remove centre console and glovebox. Remove 'L' bracket at left of cooler box and there is some surrounding bolts and screws and out the box will come. Some of the clips that join the box together can be tricky but saves the grief of pulling the whole dash out.
Cheers.
AndrewA4q96

Posts: 171
Registered: 01/23/04
Re: AC Evaporator replacement
Posted: Sep 1, 2005 9:42 PM   in response to: corradoman in response to: corradoman
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Does the method you suggest work on a 96 car? I ask as bentley states a similar method to what you describe for model years 97> but states the entire dash has to be removed for 96 (just my luck). I am just about to pull the dash out, but will hunt around under the dash to see if it looks possible with leaving it in place. It would be a ton easier!

If it can't be removed in this quicker method, do you think it would be possible to change the cores (heater + evaporator) by removing the dash, but leaving the cross brace in place, then loosen the cross brace to pull it forward a little to access the cores from the top? I think I should be able to slide the heater core out this way (vertically up out of the HVAC box) but I can't find any images of how the evaporator core fits into the box, so am unsure if this technique will work on it? Can you tell me how the evaporator core is installed into the HVAC box?

Thanks for the help!
corradoman

Posts: 107
Registered: 02/14/04
Re: AC Evaporator replacement
Posted: Sep 2, 2005 3:40 AM   in response to: AndrewA4q96 in response to: AndrewA4q96
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If you are going to replace the heater core you will need the dash out. The Evap can be done on any A4 without dash removal but if you are doing the heater core too then the dash will have to come out. The dash skin seperates from the cross member. One little worthwhile tip if you are taking the dash out is when you remove the Photo sensor on the top of the dash to tie a piece of wire to this. This will help you feed it back through when refitting the dash, you will see what i mean when you get to that stage but this will save you loads of time and grief.
Good luck
AndrewA4q96

Posts: 171
Registered: 01/23/04
Re: AC Evaporator replacement
Posted: Sep 2, 2005 8:38 AM   in response to: corradoman in response to: corradoman
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I am guessing that lower half of the HVAC box is seperated by removing the blower motor, then all the little silver clips along the front edge? After removing these, the lower part of the case can be lowered revealing the evaporator?
AndrewA4q96

Posts: 171
Registered: 01/23/04
Re: AC Evaporator replacement
Posted: Sep 2, 2005 10:52 PM   in response to: AndrewA4q96 in response to: AndrewA4q96
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I have removed the entire dash and replaced the heater & evaporator cores. Thanks for the hint about the photo sensor on the dash, I very nearly forgot to thread that back up on re-installing the dash! I still have not finished the re-assembly, but with any luck the car will live to see another day :)

I now realize why the dealer wanted > $2500 USD for this job, it's not a couple of hour task!
Highfructosecor...

Posts: 1
Registered: 08/13/13
Re: AC Evaporator replacement
Posted: Aug 13, 2013 4:51 PM   in response to: corradoman in response to: corradoman
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Could someone direct me to a diagram or some detailed instructions on removing the evaporator without removing the dash?

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