[s-cars] 93 S4 heater issues

[Sam Clarkson]

Hey Tom
I REALLY SUCK you know!
I've shorted the vac hoses together to hold that valve open and the  
hose gets warm on the downstream side of the tap. So I figure that's  
not the issue. Still no heat in the cabin though even with hot hoses.  
The system went spastic prior to failure, the only way to stop heat  
was to go full cold. So servo motor it will be I guess. I'll play  
with the codes.
Sam Clarkson
Edge to Edge
P.O. Box 27
National Park 3948
Ph 0800 800 SKI (754)
http://www.edgetoedge.co.nz

On 26/04/2007, at 3:28 AM, Tom Green wrote:

> Sam,
>
> The heater control valve usually has a lot of resistance and is  
> hard to move the lever
> up by hand.  It illustrates the strength of the vacuum system when  
> given a little
> mechanical advantage, so I am surprised you can move the valve with  
> mouth suction.
> You may want to remove the valve to verify it is intact and  
> operating properly.  This is
> a very inexpensive part on the aftermarket here and all I have  
> bought are OEM parts
> with the Audi logo marked over.  Just be careful removing any  
> parts.  The hoses are
> usually stuck tight to the plastic nipples so it is easy to break  
> them.  The heater inlet
> nipples are plastic as well, and the small rubber connector from  
> the valve to the
> heater core inlet is a high value part (has a plastic air bleed  
> screw on top) so take care.
> It should be obvious that the small nipples for the vacuum  
> connectors are fragile as
> well.
>
> Check out the knowledge base and FAQ section at audifans.com.   
> There is a lot of
> information about the system as well as repair experience on that  
> site.  You can see
> the inlet and outlet hoses for the heater under the plenum cover.   
> The outlet is below
> the inlet with the vacuum controlled heater valve so you can verify  
> that heat flows into
> and out of the heater core by feeling the hose temperature with the  
> system in the heat
> mode as well as observe the lever on the side of the water tap  
> move.  Look at the
> diagnostic procedure for the HVAC.  If any of the flaps and valves  
> are not operating,
> error codes will be displayed on the automatic climate control  
> head.  I would clear
> any codes and operate the system a while to see if they return  
> before replacing parts.
>
> If the heater core is plugged, there are details for replacing it  
> on audifans as well, but
> let's hope we don't have to go there yet.
>
> Tom
>
>> Date: Wed, 25 Apr 2007 15:58:07 +1200
>> From: Sam Clarkson <sam at edgetoedge.co.nz>
>> Subject: [s-cars] 93 S4 heater issues
>> To: s-car-list at audifans.com
>> Message-ID: <CFD21E9A-C2E5-4F84-B1E4-C589F9485ADA at edgetoedge.co.nz>
>> Content-Type: text/plain;	charset=US-ASCII;	delsp=yes;	format=flowed
>>
>> Team
>> No heat, winter approaching here on the top side of the planet. I've
>> pulled off and sucked on the vac line to the water tap and its  
>> moving/
>> working fine. There is good vac to the solenoid that controls the
>> tap, even when the engine's been off for hours, so no vacuum issues.
>> Can I swap that solenoid with the other one (what does it do) to
>> test?. Can I test voltage to it, what readings am I looking for at
>> hot and cold? What else?
>> Love you always
>>
>>
>> Sam Clarkson
>
>
>