That is all it takes in warm weather, a tiny leak. Check any new valve
the same way. If you can blow though it at all when closed, reject it.

Mark

Shawn Wright wrote:

> While replacing my rad, I also removing my front heater control valve, since
> I still seemed to be getting heat in the core even with the valve fully closed. I
> had already checked that the control cable was closing it all the way.
> Blowing in the valve shows that there is some leakage, but not a lot -
> blowing as hard as I can produces a barely noticeable amount of air coming
> out the other side. This doesn't seem like enough to cause the amount of
> heat I'm getting in the core - enough that it's uncomfortable to drive when
> hot out just from the air coming out of the vents with the fan off.
>
> I recall others commenting on this valve leaking. How much does it have to
> leak to be a problem? Is there some other explanation? Could reversing the
> flow from the engine cause the problem? (I may have done this in error
> when installing my TD).
>
> Thanks.
>
> Shawn Wright
> http://members.shaw.ca/vwdiesels
> '88 Westy 1.6TD 5 speed
> '85 Jetta Diesel 1.6NA
>