Someone help freezing wife...heater problem

[bibbs]

Hey I'm new to these forums but have been on the Vortex for a while under the same username.

My wife's '01 A4Q 1.8T is having heat issues. So far: The car reaches operating temperature in a normal amount of time and maintains it (Thermostat OK), both hoses into the heater core are warm and seem to have flow, the coolant has recently been flushed and the mix is good, I tried forcing any air out by revving the engine for a few minutes with the coolant reservoir cap off and I seemed to be able to get some heat at that time but then under normal operating conditions the heat goes away again which leads me to believe that it's not airlocked. Could this be an Actuator/flapper issue? The car is climatronic and I dont know how to diagnose or locate the modules that allow flow through the core. If anybody can help or provide a link to a diagram of the heating system or Bentley scans that would be great.

[djwimbo]

It's possible there's air in the system. Unfortunately it's a PITA to bleed our cars if there's a bubble/pocket in the heater core.
So, when they built our cars they put a special hose with a hole in it to the heater core. You probably have a battery/cowl cover, pull it off and take a look at the hoses to the heater core. One of them will have the hose installed on further than the other. Take a close look. There should be a hole in it past the clamp(to prevent leaking), it should be a ~.125-.175" hole.

Basically what they want you to do is hold the RPM's at ~2500, loosen that clamp and pull the hose back so that the hole is exposed to the coolant. Don't remove the hose from the heater core, just pull the hose back enough. That is supposed to bleed the air bubbles out of the system. It works most of the time.
Personally I've had better success with the venturi vacuum system, but I don't expect you to go out and buy one.

That's one of the processes. I doubt you have an issue with this as your car is newer, but we had a problem with the older cars Audi 80/90's, 100's, C4 A6's, etc. Over time and zero maintenance the cars can get a build up of nastiness, goo, rust, oxidization, etc, guess where? In the heater core. We rigged up a 5 gallon bucket and an electric sump pump as a "flush machine". We used a couple bottles of the "radiator flush" from Napa and mixed 50:50, or sometimes 66:33, and ran it through the flush system. This has worked on most of the cars known to have the crap built up in the heater core, I'm not saying it's a fix all.
A couple months after our Sr. tech started trying that method, there was an article about somebody else doing it down south with decent success.

I don't know if you take your car to a tech or if you fix stuff yourself, but I'd talk it over with your tech if you have one.

[bibbs]

Thanks for the quick reply I will try the method you recommended. If it's still not purged after this, should I remove both hoses into the core and backflush it?

[djwimbo]

... should I remove both hoses into the core and backflush it?

I've done that a couple times, it's less effective than the deal with the pump and solvent, but it has worked.

Last time I did it(that it worked) I did it with a garden hose, and it took a 20-30 mins to get clean water out. I would randomly grab a 5 gal bucket and catch some of the water coming out and inspect it. It would have small dark grainy looking stuff, or when I first started flushing it it all came out brown

[le91688]

I'll help you freeze your wife!

[maxspeed]

ill help you warm up your wife

[bibbs]

Uhhhh...inappropriate?

[djwimbo]

Uhhhh...inappropriate?

I had a customer at the first Toyota dealer I worked for tell my his A/C wasn't cold enough. He couldn't get his wife to reach NET.

I asked him what NET was. His response, "Nipple Erection Temperature".

I laughed and told him I'm pretty sure I won't need his wife to verify proper operation of his A/C.

... He had a bird's beak in his A/C condenser BTW

[InTTruder]

There is also a servo-operated flap that can stick/fail. That may require some additional diagnosis.

[bibbs]

InTTruder, can I diagnose this via VAGCOM, or any other method?

[InTTruder]

InTTruder, can I diagnose this via VAGCOM, or any other method?

My tech used VAGCom to get that specific. I thought I was having flow issues, but it was the flapper. We accessed it (biyatch) and did some tweaking. It can be expensive at the dealer.

[maxspeed]

Uhhhh...inappropriate?

welcome to the internet.

[bibbs]

Just looking for helpful info, that's why I came here instead of the 'Tex, not looking for idiots trying to up there post count.

[BADB5A4]

Hey bibbs,
You can access some of the diagnostics through the HVAC control unit if you dont have access to a VAG-Com. You can manually operate the window,footwell and center vents using this to at least tell you if the motor is working...

Here a link that might actually be relevant -
http://www.audiworld.com/tech/int.html

PS - I might have also responded to you on VWortexx

[InTTruder]

I haven't used the HVAC contyrols to modulate the flappers. Might try that as a diagnostic.

[bibbs]

I ran the diagnostics within the Climatronic system and got zero fault codes, I can hear all the flappers moving when activated and I'm at a total loss. Today I'm going to backflush the core being that it's just barely freezing and will post the results but I'm not too optimistic because the heater hoses are both warm at operating temp???????

[InTTruder]

Weird, if both hoses are EQUALLY warm (hard to tell), then you have no flow. The one coming OUT of the passenger bay/heater ore should be a bit cooler, since it's giving heat up to the cabin.

[bibbs]

It ended up being air in the system, I bled it through the relief hole in the heater hose for 10 minutes twice and that seemes to have cleared it up. Thanks for all the suggestions.