[T3] Thermostat Air Flap

[Jim Adney]

On 23 Jun 2011 at 16:25, J. Jonik wrote:

Sounds like things are going fairly well to this point.

> The thermostat is mounted below and screwed all the way onto its rod.
> Doing that brings the flap-rod, above, as close as possible to where
> it anchors to the assembly.      BUT...to get the rod in the anchor
> enough to tighten the little bolt, the flap ends up almost all the way
> open.   According to Bentley, it should only be open a fraction of an
> inch. 

Yeah, this doesn't sound right.

>  I'm assuming that when adjusting all this, the engine is cold (though
> its in upper 80s today), and the thermostat is in most-compressed
> state.   It expands when heated, right?   But the thermostat takes up
> all the up-and-down space in its bracket. Where can it expand to?   Is
> that top extension (with the hole to screw into the rod) supposed to
> ride up and down in its notch as thermostat temperature changes?  As
> it is, it can only go down. 

If the thermostat fills its bracket, it's broken. It should only fill 
about 3/4 of the space, so that it can expand and then hit its 
"ceiling." Finding a good one can be a problem if you don't have a 
stash.

To adjust them, I usually release the bolt on the bottom and let the 
spring pull the thermostat up until it hits the ceiling, so it's wide 
open when the thermostat is fully extended. Then I bolt the 
thermostat down and accept whatever gap that leaves under the flap.

> Another ominous problem (besides flap rod not being long enough) is
> that the spring is too long...by about an inch. 

VW used a bunch of similar but different springs in various places on 
various models. They often get mixed up, which is what this sounds 
like. You can modify this one or buy something suitable. It's not 
really critical, you just want it to be strong enough to pull the 
flap open if the set screw on the pull rod comes loose.

> So....maybe the question is....Is this the right thermostat and
> assembly for a 72 standard engine?    I have a 73 parts car out back.
> But I'll bet there's no thermostat etc there to look at.   

It's the right thermostat; I think there was only one that would fit. 
(Type 4 engines used a slightly different one.) This one has just 
lost some of its vacuum. If you squeeze this one with your hand, you 
will see that it will compress. A good one won't compress because 
it's already down to its internal stop.

If you don't have one there, you might try some shops in your area or 
a junkyard. One from a beetle or pre-72 bus would be the same.

There are new ones, but they are expensive and they don't fail 
extended. Try to find a good used one.

-- 
*******************************
Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
*******************************