90q20v heater valve kablooey
kf21857 at comcast.net
kf21857 at comcast.net
Mon Nov 20 15:13:17 EST 2006
Thanks, that explains why my @#$#$ air conditioner never has worked right. It takes a loooong time to cool down once you switch it on. I may be able to glue the old valve back together with PVC cement but where the vacuum hose went is still a mystery. I thought it might originate at the controller but I thought I should check before I started tearing the dash apart. Thanks for your help.
-------------- Original message --------------
From: Kneale Brownson <kneale at coslink.net>
> The vacuum hose should come from the climate control controller. It should
> shut off the heater valve while the A/C is in operation. Probably lowers
> the ambient air temp in the heater core box, where the air passes through
> without going directly over the heater core when heat isn't called for,
> from ~200 degrees F to whatever the outside air temp is.
> The version of that valve with the sensor is NLA. You can replace the
> valve with a metal version from FLAPS for around $20. The plastic valve
> without the sensor is available from most import parts sources for a
> similar price.
> At 04:44 PM 11/20/2006 +0000, kf21857 at comcast.net wrote:
> >Hi, I am a former list member but haven't been subscribed in a while because
> >my car hasn't broken in a long time.
> >My 90q20v with climate control has a vacuum actuated valve with a water temp
> >sensor in the heater hose a few inches from where it enters the firewall.
> >Yesterday the two halves of the valve separated while I was stopped in
> >traffic, causing the cooling system to empty itself rather quickly.
> >Fortunately I was able to find a parking spot, remove the two pieces from
> >the heater hose, unload the mountain bike I had on the roof and cycle to a
> >hardware store to find a suitable part to splice the hoses back together.
> >Here are my questions. I am planning a parts run to the local Audi dealer
> >to order a replacement today, but I have spent quite a bit of time searching
> >for the vacuum hose that is supposed to control this valve and it simply
> >isn't anywhere to be found. I had noticed the valve before and wondered why
> >there was no hose going to it but had concluded that there just wasn't
> >supposed to be one. The valve defaults to open position when there is no
> >vacuum applied so the heater works OK. Exactly what is the function of this
> >valve and when is it supposed to be closed? Could this be the reason why my
> >A/C has never worked worth a darn? And where is the hose supposed to
> >originate? The Bentley shows a schematic with all of the vacuum operated
> >controls on the heater but I haven't found anything telling me where to find
> >it. I am guessing that it is under the dash somewhere. Do I really need to
> >replace this thing? Is it vitally important? It looks rather expensive and
> >I have made a semi p
> >ermanent repair by clamping a pipe nipple in place of the valve.
> >quattro mailing list
> >quattro at audifans.com
> >Watch this space for ads :)
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