How does a different thermostat affect the gas mileage?

Mr. BZ-like water for chocolate?

On Feb 26, 2009, at 12:15 PM, Mike Collum wrote:

> Keith Ovregaard wrote:
>> Anyone experience lower mileage after installing a new 87 degree
>> (stock) thermostat?
>
>
> My gas mileage improved after replacing a failed open thermostat.  I
> used the 87� version.  I had my old 1.9 engine in the '85 Westy at  
> that
> time and I went from about 17 mpg to about 20 mpg at 60 mph.
>
> Now I have a 2.1 in it (with an '87� thermostat) and I'm getting just
> over 22 mpg at 60 mph.
>
> Mike