terryn

Well after an audi diagnostic revealed some servo fault codes. I removed all of the lower panelling inside (glovebox) etc to reveal the two lower servos. Yes the red one on the left works fine but the blue one is stuck. I will attempt the servo repair as shown in other posts. Disconecting the arm and moving by hand has eliminated a stuck flap. As the servos are morm driven it can't be manually set for now.
Now to address the heat at 3000rpm is almost certainly a plugged matrix. Can't decide whether to remove the whole box and do the lot or just try and tease out the dodgy servo at this point. I think this problem has crept up on me over the years and has only just become obvious now I live in a -30 climate.

jossa

ok.. anything else that i shuld change while i am in there?

gaskets ore hoses etc.?

and one last thing.. where to order it from? i want OEM part (think that is safest)

Ben2

I think that's about all that I know of. Genuinevwaudiparts.com is a audi dealership that sells only OEM parts. For non-oem autohausaz.com is good. For used parts force5auto.com (you have to email them most parts aren't online) is unbeatable.

terryn

Well I've now replaced the matrix and repaired the servo and everything is great now. Pretty much it went how all the sites say. I didn't have to take out the centre console just the footwell parts. I'd say 4 hours and apart from the replacement part being a tad shorter no problems. Just glued some foam to take up the space. I can see the need for sealing the matrix in.

terryn

Oh and I cut the old heater open and major sludge. I can see why flushing isn't very effective. And the servo motors just needed the graphite dust cleaning to allow the brushes full contact. Cheap repair all in all.

Ben2

Good deal. The sludge forms when two incompatible coolants get mixed together. Make sure to only use the OEM Pentosin coolant.

Ben2

Also, if your HC was that sludged up your radiator might be the same if it hasn't been replaced. You can get a good one on ebay for around $150 http://forums.quattroworld.com/a6100/msgs/6601.phtml

jossa

Ok, this realy makes me optimistic :-D
I have orderd a new heater core and the fan motor, i am also going to clean the servo motors :-)

Pictures and a smal howto wil follow i guess :-)

And thanks for the tip on the radiator! I am going to order me one.

Can anyone explain what happens with the glycole when it reacts?
I know from my work that the glycol that we use reacts wit other brands, and it is the rustinhibitors reacting, and not the glycol itself that makes the sludge, is it the same here?
And could i use blue glycol if i flush my system out with water? How important is this expensive ''vag glycol"? Do we realy need to use it?

jossa

i know i am a bit late here :P


anyway...

the problem was that a baffle inside one of the end tanks of the core hade broken off and caused a direct bypas of the entire core, when i reved the engine the amount of water incresed and maxed out the bypas and some of it went into the core itself..

so it was leaking but not to the outside...

can anyone reminde me why we drive audi? feels like it is failing me all the time.. :P

Prospeeder

I did a heater core in my 100, you dont need to remove anything but the lower panels of the dash and the glove box. I was easliy able to reach behind to get the blue and red connectors that they want you to remove the climate and radio to get at.

Also your fine using green antifreeze. Its not going to hurt a thing. I wouldnt mix them, but as a complete flush and subsitute its fine. Just service it every few years. I see cars roll in constantly new to old Audi/VW with green.