[Vwdiesel] thermostat?

[William J Toensing]

I have picked up an observation that I don't think anyone else has mentioned. If interested in maximum MPG come summer, drive is a way that would not cause the temperature to rise off cold, if it was zero outside. This is of course is something I & I assume all of you already knew, that high speed decreases MPG. At 40 MPH, zero F, not enough heat generated to make heater work, but at 65 MPH enough heat to keep you warm. The more heat generated, less MPG due to energy needed to push air. In summer, a steady 40 MPH would probably equal  fantastic MPG since the engine would then heat up enough to reach maximum efficiency. This explains why MPG is worse in winter. One of the reasons I moved from Minnesota back in 1969. However, the main reason was I hated cold snowy winters with salt covered roads that caused many cars back then to rust out in 3  to 4 years or with some cars such as 1957 to 1959 Plymouths & Dodges. 
Bill Toensing, Nevada City, CA