[T3] Old Type IIIs (cooling)

[Jim Adney]

On 23 Feb 2011 at 20:24, Daniel K. Du Vall wrote:

> Could the air flow be one reason that VW changed the direction of the
> intake lovers on the sides from the early to late models? 

I can never keep track of this. Didn't they change it twice?

I thought they faced "forward" in the early years, then switched to 
"rearward" around '67-8, and finally back to "forward" in ~'70.

This is a complete guess, but here how I suspect it went:

In the beginning they faced forward because that seemed the 
reasonable way to go for best airflow. Later on, with more 
experience, they discovered that the forward facing louvers picked up 
a lot of snow, dirt and insects so they did some testing and 
discovered that the boundary layer air there wasn't moving very fast, 
so there was little airflow disadvantage and a large debris advantage 
to facing "backwards" so they changed.

But people noticed the "backwards" louvers and assumed the German 
engineers had done a stupid thing, so every engine failure suddenly 
got blamed on poor airflow. To stem this PR reaction, VW had a recall 
program where they would replace those louver sections with ones that 
faced forwards, if you complained.

Finally, VW relented and faced the louvers "forward" again just to 
minimize nusance warrantee claims.

Again, that's just my guess at what went on behind the scenes. My 
'68, with backward louvers, got driven hard but never had a cooling 
problem.

Someone else may have a better memory of when these changes occurred.

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