I can't figure out why the heat isn't working in an 1986 Audi 5000s.

I've backflushed the cooling system and checked for blockages; everything is
okay.

I noticed however that if I disconnect the coolant hose at the back of the
engine block while the car is running, no coolant rushes out. Also the
return pipe from the radiator core doesn't get hot.

I would suspect a bad water pump, but the engine doesn't overheat, and the
radiator gets properly hot.

Any ideas out there before I pull the water pump just to make sure that's
not the problem?

Regards,

Worth Winslow

 

May be the heater control valve isn't working or the vacuum line that
operates it is not operating or attached. The valve is in the same lines
that you have disconnected from the back of the block.

If this turns out to be the problem, replace the valve with a steel one
from Napa rather than the plastic one from Audi. The plastic ones are a
guaranteed failure in hot summer conditions.

If the vacuum line isn't working you will need to check the controller
inside, up behind the glove box.

Tony
'91 100q 5spd

Sarah Hirsch wrote:
> I can't figure out why the heat isn't working in an 1986 Audi 5000s.
>
> I've backflushed the cooling system and checked for blockages; everything is
> okay.
>
> I noticed however that if I disconnect the coolant hose at the back of the
> engine block while the car is running, no coolant rushes out. Also the
> return pipe from the radiator core doesn't get hot.
>
> I would suspect a bad water pump, but the engine doesn't overheat, and the
> radiator gets properly hot.
>
> Any ideas out there before I pull the water pump just to make sure that's
> not the problem?
>
> Regards,
>
> Worth Winslow
>

 

Was this valve part of the Audi 90Q design in 1995? My heater works but
does not
keep the car warm below 40 degrees. The air comes out of the vents luke
warm but when
it's moving it still makes your feet cold. The system seems to try to make
up for this by blasting
slightly warm air.


Gene


"TonyJ" <tonyjNOSPAM@NOSPAMvisi.com> wrote in message
news:3fd7bd22$0$41292$a1866201@newsreader.visi.com ...
> May be the heater control valve isn't working or the vacuum line that
> operates it is not operating or attached. The valve is in the same lines
> that you have disconnected from the back of the block.
>
> If this turns out to be the problem, replace the valve with a steel one
> from Napa rather than the plastic one from Audi. The plastic ones are a
> guaranteed failure in hot summer conditions.
>
> If the vacuum line isn't working you will need to check the controller
> inside, up behind the glove box.
>
> Tony
> '91 100q 5spd
>
> Sarah Hirsch wrote:
> > I can't figure out why the heat isn't working in an 1986 Audi 5000s.
> >
> > I've backflushed the cooling system and checked for blockages;
everything is
> > okay.
> >
> > I noticed however that if I disconnect the coolant hose at the back of
the
> > engine block while the car is running, no coolant rushes out. Also the
> > return pipe from the radiator core doesn't get hot.
> >
> > I would suspect a bad water pump, but the engine doesn't overheat, and
the
> > radiator gets properly hot.
> >
> > Any ideas out there before I pull the water pump just to make sure
that's
> > not the problem?
> >
> > Regards,
> >
> > Worth Winslow
> >
>

 

That's a good thought but I removed that valve completely and replaced it
with a straight through pipe (and garden hose connector) from a Prestone
flush kit. It was stuck open anyway as far as I can tell.

Thanks,

Worth


in article 3fd7bd22$0$41292$a1866201@newsreader.visi.com, TonyJ at
tonyjNOSPAM@NOSPAMvisi.com wrote on 12/10/03 7:45 PM:

> May be the heater control valve isn't working or the vacuum line that
> operates it is not operating or attached. The valve is in the same lines
> that you have disconnected from the back of the block.
>
> If this turns out to be the problem, replace the valve with a steel one
> from Napa rather than the plastic one from Audi. The plastic ones are a
> guaranteed failure in hot summer conditions.
>
> If the vacuum line isn't working you will need to check the controller
> inside, up behind the glove box.
>
> Tony
> '91 100q 5spd
>
> Sarah Hirsch wrote:
>> I can't figure out why the heat isn't working in an 1986 Audi 5000s.
>>
>> I've backflushed the cooling system and checked for blockages; everything is
>> okay.
>>
>> I noticed however that if I disconnect the coolant hose at the back of the
>> engine block while the car is running, no coolant rushes out. Also the
>> return pipe from the radiator core doesn't get hot.
>>
>> I would suspect a bad water pump, but the engine doesn't overheat, and the
>> radiator gets properly hot.
>>
>> Any ideas out there before I pull the water pump just to make sure that's
>> not the problem?
>>
>> Regards,
>>
>> Worth Winslow
>>
>

 

>>> I noticed however that if I disconnect the coolant hose at the back of the
>>> engine block while the car is running, no coolant rushes out.

then that is where you need to start from.
it seems like it is clogged and I would rod it out or probe in that pipe.
coolant should flow very freely out of that pipe. I don't think the Audi 5Ks
have any restrictors in the hoses, but they might.
DO THIS CAREFULLY AND AT YOUR OWN RISK!!!!!!!

later,
dave
Reminder........
Before you criticize someone, you should walk a mile in their shoes. That way,
when you criticize them, you are a mile away from them, and you have their
shoes. Frieda Norris