[T3] type 4 2000cc oil pressure and overheating problem

Jim Adney jadney at vwtype3.org
Sat Dec 10 09:54:22 PST 2011

On 10 Dec 2011 at 10:07, Bobsnotch at aol.com wrote:
> If you look at the cooling slots under the rear window of a Notch, you'll  
> see that area is actually slightly smaller (surface area) than the 2 sides 
> of a  Square, or Fastback. It's also a low pressure are like the front air 
> vent (in  front of the windshield), so it's not pressurized. It (a Square) 
> should actually  have better cooling air intake flow than a Notch. 

I think the area in front of the windshield is actually a high 
pressure area (I'm guessing that's what Bob intended to say) but I 
agree that I expect the area behind a notch rear window to be a low 
pressure area. I agree that the larger louver area and simpler 
airducts should provide better cooling in the squares/fastys.

This airflow/pressure question is a good one for our aero experts. 
What do you think, John?

OTOH, I've always wondered why VW did the notch differently. It 
should probably be noted that GM did something very similar in the 
Corvair (or were those louvers in the Corvair rear deck lid?  

> What makes you think the t-3 fan is 2 stage? I know the belt pulley has  
> vanes in it, but I've always thought they were to straighten out the air flow  
> into the large fan.  

I suspect the vanes in the Type 3 pulley have some positive effect, 
but I don't know how large it is. I wouldn't be surprised if they're 
just enough to assure that the pulley is not an impediment to 

I'm gonna have to take a look at a Type 4 manual, but isn't there 
anything similar on the Type 4 engine?

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

More information about the type3-vwtype3.org mailing list