teeka56

'87 5K. Blown core. Where are the screws that hold the unit it the firewall? Bentley just says remove the screws?? WHere I have the unit ready to pull out. Thanks

xjrpilot

i have a bad heater core as well. the DPO (dumb previous owner) mentioned that it was leaking so he bypassed it. how hard is it to replace? how much for a new one? how much of the dash do i have to remove? so many questions so little time before winter. does anybody have any links to a audi repair web site? my haynes manual does not cover the heater core. at least not very good.
emanuel

DaveN

because it is about a half day job. The heater core is in the big white plastic box on the top of the fire wall under the cheap black plastic cover. Pull the wipers (careful of the windshield, it will crack if you let them snap down), then carefully work the black plastic cover off. The heater box is in the center. Pull the two hoses that go to it though the firewall (drain some coolent off first), disconnect the fan motor (on the driver side), any control cables (I think there are two, but it has been a while), and then loosen the large metal strap with the single screw. Then go behind the dash and pull the air ducts off either side as well as any vaccum control lines. You will have to pull the panels off on the drivers side as well as the glove box to do this. Once you think you have everything off go back up top and start pulling the box upward. It is held in using double sided tape all the way around so it will not break free easily. Be careful and look for anything you might have missed as you pull it out. It should take a lot of force at first, but then almost nothing as it comes up, if you encounter force after it has broken away stop and see why, alot of these parts are expensive and a pain to get, so it is easier just not to break them in the first place. Once you have it out you can beack it open to get to the core. The box splits vertically and is held together using metal clips. Take care when you open the box as the control doors will want to fall out, just go slow so you can see where they came from. You can then replace the core. Another word of advise: while you have it all apart replace the brushes in the motor (another weak point, and not worth taking it apart again), as well as lub the ends of the air doors. This does wonders for having the system work smooth, as well as taking some of those annoying sounds out. Good luck with it.

teeka56

Ok I like the answer- but- I have box kinda free, it wasnt all that tight. But Im not clear on whats behind the dash? I pulled the lower pass shelf out. Yes there are ducts. Is there an inside connection to the white box? Are there fasteners? Or is it the ducts that make it not come out. I have done all that you mention- just need to be clear about the ducts. THe bentley book is confusing- it shows the AC side and says remove the 4 screws. I see these screws, but it looks like they are for the AC unit/flap and do not line up with white box at all. Thanks very much for this info.

xjrpilot

before i start this project, has anybody attempted to use some barrs leaks or any other cooling system sealer to try sealing the leak in the heater core? i figure if i run the heater all the time while driving for a couple of days it might just seal the leak. will trying this hurt the the radiator? will it hurt to try? i can always flush the system if it doesnt work.

teeka56

Ok.. I found the screws that hold some lateral ducts to the unit. There were 4, very easy to get. You have to remove the wiper assembly.Pretty easy. Then the unit will lift a bit, mine wasnt stuck in very tight at all. Found a yellow and a green wire connector on the drivers side, disconnect those. Then I saw 3 vaccum lines on the servo units. Very strange connection. Small phillips hold them in place. The unit came out easy after that with a long wire harness.The Bentley book is really vague on this whole deal. Its really not too bad if you know WHAT to remove. I think I will change the fan motor since Im this far and have this much timeinto it. I replaced all the hoses while I am at it. They were only $35 for all. The ones on mine were ok but after 325,000 miles I figured it was time.Thanks for the advice.