A4 (B5 Platform) Discussion Discussion forum for the B5 Audi A4 produced from 1995-2001 B5 FAQ

Another no heat thread! please help!

Thread Tools
 
Search this Thread
 
Old Feb 13, 2013 | 09:16 AM
  #11  
gtrjon's Avatar
Thread Starter
Audiworld Junior Member
 
Joined: Feb 2013
Posts: 13
Likes: 0
Default

Originally Posted by 4Driver4
That the vent for the battery.

Did you bleed the system yet?
Touche it is the battery vent. Ill be bleeding the system yet again tomorrow at my buddys shop so i can throw some pressurized air through it. Ill update any progress. Cheers
Reply
Old Feb 14, 2013 | 06:16 PM
  #12  
gtrjon's Avatar
Thread Starter
Audiworld Junior Member
 
Joined: Feb 2013
Posts: 13
Likes: 0
Default Lots of codes still no heat

Alright so i finally got in the shop where i had access to an air compressor. I started by first pumping some air into the system to make sure it was fully bled. Nothing still no heat. I then tried to pump some air directly into the heater core both in normal flow and in a reverse flow still no heat. I then tried the chemical soak with some drain cleaner. I let it soak for 2 hours and then thoroughly flushed it and bled it still no heat. I then started to think it may be the flaps but I can hear them working when i turn the blower on and off. I then used the on board climate control to pull off the diagnostic codes. There were 6! they are hard to decipher since some of the pixels are shot in the screen. any ideas? id really like to have heat. To summarize:

Bled system with compressed air
Flushed heater core with water and compressed air
Chemical soaked heater core and flushed
Have 6 codes on the climate control.

Still no heat!!! ???
Reply
Old Feb 14, 2013 | 06:22 PM
  #13  
gtrjon's Avatar
Thread Starter
Audiworld Junior Member
 
Joined: Feb 2013
Posts: 13
Likes: 0
Default

I forgot to add that the heater core inlet hose is piping hot and the outlet hose is just warm but not really hot to the touch...
Reply
Old Feb 15, 2013 | 07:20 AM
  #14  
M3Armand's Avatar
Audiworld Junior Member
 
Joined: Mar 2007
Posts: 34
Likes: 0
From: Los Angeles, CA
Default

Originally Posted by 4Driver4
Bleeding, not flushing.

I use a large rubber stopper with a hole in it and a blow gun. Fill the tank to the correct level and blow a few pounds of pressure into it. At the same time, bleed each heater core hose at the core.
I don't get it. I was just going to reply to this thread since I used to have a heater core problem, by backflushing fixed it. So I read the above and I want to learn how to do this correctly in the event that my heat goes away again. So to check my understanding:

1. I'll get a hose with a rubber stopper with a small hole in it OR I can just use a hose small enough for my blow gun.
2. When you say "fill the tank to the correct level", I assume you mean the white G12 coolant tank? I don't understand what would blowing air into it do?
3. At the heater core, I assume we need to remove the current hoses going into and out of it. Then replace those hoses with one small enough just like #1 above. Using the blow gun, put some air pressure in it so that any fluids would shoot out the other end.

For #3 above, wouldn't running water continuously through the heater core produce a better desired effect of getting rid of any "gunk" in there vs using air? I ran mine for maybe 15-20 minutes "just to be sure" and replaced the fluids with brand new G12 (since the old fluid may have been contaminated with different coolant mixtures which could produce some solids as I've seen in this forum somewhere).

Before, I just used to backflush the heater core. But the problem kept coming back. When I completely used new G12 and backflushed the system, the problem hasn't returned.
Reply
Old Feb 15, 2013 | 04:59 PM
  #15  
4Driver4's Avatar
Tech Guru
20 Year Member
Tech Guru

 
Joined: Oct 2002
Posts: 34,430
Likes: 130
Default

Originally Posted by M3Armand
I don't get it.
You are ovethinking this. I'm talking about bleeding the system using compressed air rather than waiting for heat to build pressure in the system. That's it.

Fill the system with coolant. Pressure throught the fill cap. Allow any air trapped to escape via the bleed points. Simple.
Reply
Old Feb 16, 2013 | 08:49 AM
  #16  
gtrjon's Avatar
Thread Starter
Audiworld Junior Member
 
Joined: Feb 2013
Posts: 13
Likes: 0
Default

None of these responses have helped even look at my issue specifically my hvac codes! i need some help guys
Reply
Old Feb 16, 2013 | 03:59 PM
  #17  
gtrjon's Avatar
Thread Starter
Audiworld Junior Member
 
Joined: Feb 2013
Posts: 13
Likes: 0
Default

Originally Posted by noylekul
Telling us there are six codes without the codes doesn't help...

Did you ever think that the hose on the side of the heater core that only gets warm might be clogged? The hose itself, not the heater core.

By what you are explaining it sounds to me there is a clog some where, and you either need a new ambient temp sensor or to clean it off.
Go take all of your 6 posts and troll some where else. I always love when people post in threads without reading all the content. It makes so much sense that the hose is clogged omg why didnt i think about that. I mean i guess since my chemical soak didnt run through the hose. I guess when I flushed the system I didnt flush the hoses. I guess when i pushed pressurized air through the system I didnt put any through the hoses. You sir are a genius. Id love to tell you what the 6 codes are but once again you didnt read the content thoroughly or else you would know that I cant read them!! I thought the fact that there are so many codes could be a helpful use of diagnostic information regardless. Bump for someone with a little more intelligence!
Reply
Old Feb 17, 2013 | 01:57 AM
  #18  
Huskerbob's Avatar
AudiWorld Senior Member
 
Joined: Aug 2011
Posts: 1,155
Likes: 0
From: North Carolina
Default climate control codes?

Originally Posted by gtrjon
None of these responses have helped even look at my issue specifically my hvac codes! i need some help guys
Drive on down to the parts store and get them to pull the codes for you. Then we'll have a starting point.

(Do you know how to bleed the air out of the system? Pull the "out" heater hose off the nipple up by the firewall until the little hole appears on the top of it. Run the engine until water shots out and then shove it back on.)

Codes may tell the story.
Reply
AudiWorld Stories

Bringing Audi to Life for Audi Fans

story-0

The Highs & Lows of Every Audi C-Class Generation

 Joe Kucinski
story-1

Top 10 Most Expensive Audis Ever Sold on Bring-A-Trailer

 Brett Foote
story-2

10 Audi Features & Options We Miss the Most!

 Joe Kucinski
story-3

Audi Recreates Crazy-Looking Speed Record Breaker From 1935

 Verdad Gallardo
story-4

Coachbuilder Recreates the 1995 Audi TTS Concept

 Verdad Gallardo
story-5

Every Audi V10 Car Ranked!

 Joe Kucinski
story-6

9 Audi Designs That Aged Like Fine Wine

 Verdad Gallardo
story-7

2026 Audi Q5 Buyer's Guide (Every Model Explained)

 Brett Foote
story-8

Ranking Every Current Audi 'S' Model From Worst to First!

 Joe Kucinski
story-9

10 Best Audis That are FINALLY LEGAL to Import to the U.S.!

 Joe Kucinski
Old Feb 17, 2013 | 03:03 AM
  #19  
4Driver4's Avatar
Tech Guru
20 Year Member
Tech Guru

 
Joined: Oct 2002
Posts: 34,430
Likes: 130
Default

Originally Posted by gtrjon
Alright so i finally got in the shop where i had access to an air compressor. I started by first pumping some air into the system to make sure it was fully bled. Nothing still no heat. I then tried to pump some air directly into the heater core both in normal flow and in a reverse flow still no heat. I then tried the chemical soak with some drain cleaner. I let it soak for 2 hours and then thoroughly flushed it and bled it still no heat. I then started to think it may be the flaps but I can hear them working when i turn the blower on and off. I then used the on board climate control to pull off the diagnostic codes. There were 6! they are hard to decipher since some of the pixels are shot in the screen. any ideas? id really like to have heat. To summarize:

Bled system with compressed air
Flushed heater core with water and compressed air
Chemical soaked heater core and flushed
Have 6 codes on the climate control.

Still no heat!!! ???
You could clear the codes and run adaptation, but if you have one hot hose and one cool hose, your core isn't getting any flow. If that is really the case and if you as sure that the system is correctly bled, the core is plugged with crap.
Reply
Old Feb 18, 2013 | 05:42 PM
  #20  
gtrjon's Avatar
Thread Starter
Audiworld Junior Member
 
Joined: Feb 2013
Posts: 13
Likes: 0
Default

Originally Posted by Huskerbob
Drive on down to the parts store and get them to pull the codes for you. Then we'll have a starting point.

(Do you know how to bleed the air out of the system? Pull the "out" heater hose off the nipple up by the firewall until the little hole appears on the top of it. Run the engine until water shots out and then shove it back on.)

Codes may tell the story.
system is bled and flushed. both heater hoses are hot now but still no heat. I did my best to decipher all 6 of the hvac codes with the busted pixels in the head unit. Anyway this is what i came up with.

7.1 Ambient Temperature Sensor at Fresh Air Blower, static open
8.7Temperature Regulator Flap, sporadic block
15.7Air Flow Flap, sporadic block
11.7Central Flap, sporadic block
29.1Belt slip detection "soft", static
29.3Belt slip detection "soft", sporadic

Plan of action? Is it possible im actually having all of these problems? or could it be a problem with the hvac head unit? although im sure the 7.1 code is legit because my ambient temp reading is sporadic sometimes.
Reply



All times are GMT -8. The time now is 02:34 PM.

story-0
The Highs & Lows of Every Audi C-Class Generation

Slideshow: The highs and lows of every Audi C-Class generation.

By Joe Kucinski | 2026-05-27 16:05:50


VIEW MORE
story-1
Top 10 Most Expensive Audis Ever Sold on Bring-A-Trailer

People were more than happy to shell out big bucks for these cars.

By Brett Foote | 2026-05-27 15:32:23


VIEW MORE
story-2
10 Audi Features & Options We Miss the Most!

Slideshow: 10 Audi features and options we miss the most.

By Joe Kucinski | 2026-05-12 19:33:47


VIEW MORE
story-3
Audi Recreates Crazy-Looking Speed Record Breaker From 1935

Slideshow: Audi has recreated one of the wildest machines of the pre-war speed-record era, reviving a streamlined V16 racer that originally exceeded 200 mph in 1935.

By Verdad Gallardo | 2026-05-11 09:49:34


VIEW MORE
story-4
Coachbuilder Recreates the 1995 Audi TTS Concept

Slideshow: A Dutch coachbuilder has reimagined the original Audi TT by finishing what the 1995 concept only hinted at.

By Verdad Gallardo | 2026-05-05 15:17:58


VIEW MORE
story-5
Every Audi V10 Car Ranked!

Slideshow: Ranking every Audi V10 road car

By Joe Kucinski | 2026-04-29 16:11:56


VIEW MORE
story-6
9 Audi Designs That Aged Like Fine Wine

Slideshow: A look back at the Audis that didn't just survive changing tastes, they quietly outgrew them.

By Verdad Gallardo | 2026-04-28 19:38:27


VIEW MORE
story-7
2026 Audi Q5 Buyer's Guide (Every Model Explained)

One year off a full redesign, the best-selling Q5 is getting a few more updates.

By Brett Foote | 2026-04-17 09:56:19


VIEW MORE
story-8
Ranking Every Current Audi 'S' Model From Worst to First!

Slideshow: Ranking every current Audi 'S' model on sale today from worst to best.

By Joe Kucinski | 2026-04-16 10:28:28


VIEW MORE
story-9
10 Best Audis That are FINALLY LEGAL to Import to the U.S.!

Slideshow: 10 best Audis that are finally legal to import to the U.S.

By Joe Kucinski | 2026-03-24 17:20:08


VIEW MORE