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View Full Version : Heater Core Replacement Tonight...



Ryanic
11-16-2018, 12:52 PM
So i'm going to be tackling the heater core tonight and tomorrow. While i'm in there I want to look over the blend doors and ensure the foam (Is this really a thing on B5 A4s?) is still good around the different blend doors. I've been doing some research and I believe the B5 Passat has the same heater box/HVAC box right? I'm not really seeing any tips/photos of what I'm looking for when I get in there for our cars in regards to deteriorated foam. I've found tons of information about MK4 Jettas and such but I think they have metal blend doors with holes in them and we don't?

From photos of B5 A4 heater boxes online it looks like this is what I'll be expecting to see when I get in there, but it looks like its a solid plastic blend door....
https://d3inagkmqs1m6q.cloudfront.net/1517/media-pics/cp036712-heater-core-box-heaterbox-99-02-audi-a4-s4-b5-genuine-8d1-820-005-j.jpg

Does anyone have any photos or information so I'm a little bit more prepared going in tonight.

Thanks


EDIT* After completion*
So I didn't open the HVAC box up but I did notice there was a smaller plastic flap with three small holes in it in the duct that I circled. There was a little foam left on mine but they could definitely have been fixed while I was in there. I believe that duct is for directing air up towards the windows or down towards your feet so I didn't worry about it as it looked like it was after the heater core anyways

As I mentioned I didn't open the box up but from peering inside the ducts it did look like the main blend doors and center flap were 100% plastic with like a rubber edge that helps seal it. So there shouldmt be any issue with that for anyone that is also worried.
https://preview.ibb.co/ffHWc0/b5-heaterbox-circle.jpg (https://ibb.co/nsORAL)

calbernieye
11-16-2018, 05:40 PM
Pictures!!


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Ryanic
11-17-2018, 12:33 AM
This is where im at so far... Ran into a 45 minute issue trying to drop the steering column. Im about 5 hours in
https://preview.ibb.co/iSnb70/20181117-020500.jpg (https://ibb.co/hQ3uuf)

Does anyone know where this ground goes? I found it unhooked behind my pre facelife climate control module/by what ever the white thing is attached to the hvac plastic cage.
https://preview.ibb.co/mzYG70/20181116-235025-HDR.jpg (https://ibb.co/jSyin0)

Ryanic
11-17-2018, 12:37 AM
Also, i think im at the stage where i can either pull the aluminum frame or try to sneak the hvac box out under it. Id rather try to sneak it out so if anyone has any tips or hints.

Going to start on it again in the morning.

MetalMan
11-17-2018, 12:37 AM
That ground is for the stereo... as I recall it's related to anti-theft. If you have an aftermarket stereo then it's not used.

Ryanic
11-17-2018, 06:11 AM
Thank you MetalMan. I do indeed have an aftermarket head unit so i will not worry about it when i put it back together. Thanks!

rollerton
11-17-2018, 03:28 PM
I'm looking at this exact same project. But doesn't make sense...I'll have to make my own thread.

but BTW, the pre-facelift A4 is assembled totally insane. WTF. There are screws in places I can't picture any reasonable assembly line process dealing with. And if the stereo is stuck in the dash (because 300k miles OEM) you're fucked. In usual Audi style if ONE SCREW can't be removed you have to pull the dash out with a winch it looks like.
Who has a complete facelift console they want gone?

Ryanic
11-18-2018, 07:28 AM
Boy was that a pain to do. Got hung up on a few dumb spots that set me back a few hours. I think my total time was around 16-17 hours. I managed to put back every bolt though.

And this is why you have to change your heater core if flushing does nothing. When i flushed no sediment came out.
https://preview.ibb.co/nvumc0/Snapchat-1692006372.jpg (https://ibb.co/kV1A4f)

This view made me so happy. Lol
https://preview.ibb.co/dE8OPf/20181117-111313.jpg (https://ibb.co/nzqsH0)

Pulling the box out with the aluminum frame still in I think saved me a lot of time and headache. Once that dash skin is off and the 30+ bolts of the airbags there are only 7-8 bolts that hold the box in. I had to remove the black metal center console cage though (There are a couple bolts that hold the box in place on there anyways). We just unbolted everything and kind of twisted it out of the way so we could slide the box out the passenger door.


I have sweating hot heat now! Just need to bleed it a little more I think. My idle heat could be a little better but while driving I'm sweating at my temperature set to 73.

Tips

1. Mark every cable that you unplug with some tape and what it was for. It helped me a ton to make sure I didn't miss any cables while putting it back together. I tore off the tape label while reconnecting everything.
2. Some people tell you to put the bolts in bags and number them, I decided to write on the bag what they were bolted into. The less amount of the bolts per bag the better. But keep it within reason though.
3. Work in a VERY well lit area... I was working in a heated house garage and there just wasn't enough light in the car. I had to use lamps through the whole process and by the end of the two days my eyes were exhausted.
4. No need to pull the aluminum frame, save yourself some time. There are 4 hard bolts that hold the HVAC box in though, but I think I still saved time and the worry of figuring out how to put the aluminum frame back in by pulling the box from under the frame.

Just have to figure out an issue with my steering wheel being so tight and binding. I believe one of my steering wheel trims or my stalk controls didnt get put on properly.

calbernieye
11-19-2018, 01:26 PM
Nice work


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Ryanic
11-19-2018, 01:38 PM
Thanks. I figured out my steering problem as well. My turn signals and wiper stalks I guess weren't pushed all the way down so the black clam shell trim around the column was rubbing on the back of my steering wheel when I turned the car.

Feels good to have it done.

rockbeau25
11-19-2018, 03:26 PM
Boy was that a pain to do. Got hung up on a few dumb spots that set me back a few hours. I think my total time was around 16-17 hours. I managed to put back every bolt though.

And this is why you have to change your heater core if flushing does nothing. When i flushed no sediment came out.
https://preview.ibb.co/nvumc0/Snapchat-1692006372.jpg (https://ibb.co/kV1A4f)

This view made me so happy. Lol
https://preview.ibb.co/dE8OPf/20181117-111313.jpg (https://ibb.co/nzqsH0)

Pulling the box out with the aluminum frame still in I think saved me a lot of time and headache. Once that dash skin is off and the 30+ bolts of the airbags there are only 7-8 bolts that hold the box in. I had to remove the black metal center console cage though (There are a couple bolts that hold the box in place on there anyways). We just unbolted everything and kind of twisted it out of the way so we could slide the box out the passenger door.


I have sweating hot heat now! Just need to bleed it a little more I think. My idle heat could be a little better but while driving I'm sweating at my temperature set to 73.

Tips

1. Mark every cable that you unplug with some tape and what it was for. It helped me a ton to make sure I didn't miss any cables while putting it back together. I tore off the tape label while reconnecting everything.
2. Some people tell you to put the bolts in bags and number them, I decided to write on the bag what they were bolted into. The less amount of the bolts per bag the better. But keep it within reason though.
3. Work in a VERY well lit area... I was working in a heated house garage and there just wasn't enough light in the car. I had to use lamps through the whole process and by the end of the two days my eyes were exhausted.
4. No need to pull the aluminum frame, save yourself some time. There are 4 hard bolts that hold the HVAC box in though, but I think I still saved time and the worry of figuring out how to put the aluminum frame back in by pulling the box from under the frame.

Just have to figure out an issue with my steering wheel being so tight and binding. I believe one of my steering wheel trims or my stalk controls didnt get put on properly.

It took the floor mats for me to realize what I was looking at. That scene looks like a nightmare. I wouldn't wish a faulty B5 heater core on my worst enemy lol. Good work though!

Ryanic
11-20-2018, 06:49 AM
Well I guess not everything worked out perfectly... Not sure if its related somehow but last night I got home from work and after I turned my car off it sounded like some fan was still running.... I opened my hood and didn't see the radiator fan or anything running and it sounded like it might have been coming from towards my airboxish area. Didnt pin point it. I turned my car back on and then back off and the sound went away. I when to start my car this morning and the car is 100% dead. No dash lights or anything. Key fob did not even unlock the car.

Totally lost on where to even start to figure this out. Might have to go get my battery trickle charged at an auto shop and go see if I can get the fan or what ever it was to stay on again...

Any ideas? I guess I didn't check if it was the blower fan running but I didn't hear it from inside the car, only when I walked in front of my car did I realize something was still running so I dont think that would have been it.

rollerton
11-20-2018, 12:50 PM
Sucks to go through all that and have trouble when it's ALL BACK TOGETHER. I guess get it charged up and follow the sound to what is making the noise. That'll tell you if it's your fault or just another coincidental problem.
I got mine halfway done. Well, more like 1/3 probably. The various write-ups around the web help.
A couple things I found that nobody mentions is there's a 10mm bolt going UP THROUGH the front cowell above the wiper motor to a bracket for the support beam. You can get it with a wrench.
And two phillips screws that go DOWN through the dash into the relay bracket (under the dash) in the ECU box. The brackets support the entire fuse/relay panel.
The worst part so far was I had to F*&K up my dash trim because the had unit was stuck. I had to be able to get to the side of the radio so I had to REMOVE WITH FORCE the early style dash trim. It's still salvageable ..but now I have to try and find a replacement.

https://i.imgur.com/LGCGn63.jpg

https://i.imgur.com/U2lPXTF.jpg

Ryanic
11-20-2018, 02:11 PM
I did some digging and searching around today and I'm almost positive it's just coincidental. I think it's my SAI pump running 24/7 due to a bad relay. Pulled the 373 relay in the ECU box and it turns off the pump.

You went for the aluminum frame out? Yeah I had a feeling your barrier was broken too. I think its a lot more common that people think. If flushing does nothing it's most likely broken. Even though you're half way done Im sure it feels good knowing there was absolutely nothing you could do to fix it besides replace it.