Mads

Hi

I have som heating problems, everyting works fine if the heat is set to minimum, if i move the scale to get a little heat, hell breakes loose the car gets like a sauna
last weekend i was changing the oil and sparkplugs, i found a vaccum line with no connection.
looks like i'm missing the heater valve


How do i check if the vaccum n the white line is ok ?

Mads

Garth S

That's not the solution - although I can't tell what that line is from the pic ... is it on a S4?

Anyway, without vacuum, the heater valve fails open ... ie. it takes vacuum to close the flow: if you have no heat when the temp slider is hard left - and the lower lever is to the right of the OFF position, yours appears to be working.
If the temp goes off scale when you call for heat, it is likely that either the internal temp sensor ( down the hole with a mini fan behind the two louver slot in the center dash) - or the thermistor in the alternator cooling hose for the external reference temp are giving incorrect data.

Gretch

You don't say what year your car is, if it is an S4, The white line is the vacuum source for the air pump diverter valve. And yes, you ARE missing the heater valve. The vacuum source for the heater valve is a black rubber line that exits the firewall somewhere to the right of the heater valve location.

SteveG

My '85 vacuum is a white line with an elbow just as pictured. Someone has removed yours for winter warmth. If you park it slightly nose down, a cup or three of coolant will exit the line from the heater when you remove that hose. One of the easier jobs on the shark.

heinrich

That vacuum line is the heater vacuum line.

SharkSkin

I could be wrong about this -- haven't fully deciphered later HVAC systems -- but IIRC once you call for heat by moving that slider, a flap moves to admit air that has been sitting around the heater core. The system is supposed to crack the heater valve open a bit in that situation to let it warm up a little, but in your case the core is running at full coolant temp so anytime you open that air path you're going to get the sauna.

See how it behaves after you replace the valve. Pay attention to orientation, the side that says "Wasserinlicht" (Actually, the German word for water inlet) goes toward the head.

Mads

The car is a '89 S4.
I actually have a spare heater valve from my old 928, is there any difference in the model years ?
Is it correct to use the white line for vacuum to the heater valve ?
How much cooling fluid am i going to loose in the process ?

Thanks for the help so far

Mads

heinrich

It's the same

Mads

Super..

Pfunde

Nice with the aircon working - now it's finally getting warmer...... Håber at se dig i "sølvlynet" snart

Mads

Vi må lige mødes i løbet af sommeren

Mads

SteveG

See post #4.