Originally Posted by Jara (Post 25544482)

Hi I have 2000 audi a6 2.7 quattro the a/c is blowing hot air issue can you tell me some advise please thanks

Originally Posted by G-Can (Post 25544749)

and its being cold as it getting cold air from center vent...

Originally Posted by rstoer (Post 24288059)

Like many others, the air conditioning on my 2006 Audi A6 (3.2 V6) was intermittently blowing hot air from the outside vents. By now, the cause of this has been well documented as being a pump valve unit that sits between the rear of the engine and the firewall. According to Audi TSB #2013883-5, changing to an updated unit, with a B added to the original part number (4F1959617[B]) is the recommended fix. They also recommend a set of mounting parts (4F1998617). These parts alone run over $300.
Since mine worked for five years before failing I wondered if it couldn’t be repaired, but I searched all over the internet and couldn’t find anyone who even tried. So I took a shot at it, and YES IT CAN! I’ve been testing the repair for several days now and I’m convinced the problem’s gone. Here’s the best part - it takes less time and effort to repair the existing valve than to replace it. Removing one plug and six T-10 Torx screws is all it takes to disassemble the unit to the point that it can be repaired. The repair consists of cleaning some caked–on substance from the two solenoid plungers and housings. This takes well under an hour and you’ll hardly get your hands dirty. No messing with anti-freeze, hoses, or the like.

Here’s what to do…

Caution: Do this only when the engine is cold so there's no pressure in the cooling system.

Fig 1: Remove the plastic cover between the back of the engine and the firewall (not shown) by lifting the spline from the front edge and gently pulling the cover towards you. With that removed you’ll be able to see the location of the pump valve unit (yellow arrow). One plug and those two little cans are all that have to be removed.
http://home.ptd.net/~rstoer/images/1location.jpg


Fig 2: First remove the rear plug* by placing a small screwdriver where indicated by the green arrow. With the front of the blade under the plastic edge, gently press down. When you hear it click the plug will slide right off. The red arrows on my photo don’t show up too well but you can see the three #10 Torx screws across the front edge. There’s three more across the back. Remove the six screws.

* Update: Someone contacted me to say that he successfully used this method, except he left the coil assembly in the car because he had trouble removing the plug. It's true, the items that require cleaning can be accessed by just removing the six Torx screws. The coil assembly (the yellow and brown item in fig's 4 & 7) can be left in the car, tethered by the wires. Just make sure those two bronze washers (one inside each coil) are accounted for before allowing it to dangle about in the car.http://home.ptd.net/~rstoer/images/2removal.jpg


Fig 3: With the plug and screws removed, lift the two cans and the socket for the plug you just removed as one unit. Wiggle gently if needed, but it should lift off pretty easily. Be careful as one or both of the plungers may come up with the housing, making the plunger springs vulnerable to falling off. The photo shows one plunger & spring still in place.
http://home.ptd.net/~rstoer/images/3valvebase.jpg


Fig 4: This shows all the parts you’ve disassembled. (I took this photo after cleaning everything).
http://home.ptd.net/~rstoer/images/4parts.jpg


Fig 5: This photo shows the solenoid plungers, springs and washers. Note the caked-on substance on the un-cleaned plunger. I found areas of this on both plungers and the brass sleeves the plungers fit in. It’s what causes the sticking, and a good cleaning of these surfaces is all that’s needed to effect a cure. Just make sure you get it all off. I used Meguiar’s Mirror Glaze fine-Cut Cleaner because that’s what I had. Anything similar would work.
http://home.ptd.net/~rstoer/images/5plungers.jpg


Fig 6: On the housing I used a jeweler's screwdriver to gently scrape off most of the sludge, and the Fine-Cut Cleaner on a Q-Tip to get the rest.
http://home.ptd.net/~rstoer/images/6housing.jpg


Fig 7: Here’s everything cleaned up and ready to be reinstalled. When you reach this point, place the coil assembly right-side up (mine's shown upside-down), and insert a washer into each hole. Then place a solenoid housing over each coil. Finally, slip a spring onto each plunger. The nine parts should now comprise three sub-assemblies.
http://home.ptd.net/~rstoer/images/4parts.jpg


Fig 8: I found no crud on my valve base but check it and clean as necessary. Insert the plunger/spring assemblies into the valve base (only one is shown in place here). Press each one down and see that it pushes all the way in and springs back freely. Then fit the coil assembly over the plungers, making sure it seats properly on the base. Reinstall the six Torx screws and tighten. Snap the plug back into place on the coil assembly and you're ready to test.
http://home.ptd.net/~rstoer/images/8valvebase.jpg

Assuming all is well, reinstall the plastic cover and spline. That’s it!
Hopefully, this will save someone some money. These cars are expensive enough to maintain (nice to drive though).