From page 34 of the 1987 Vanagon/Transporter Volkswagen Owner's Manual

STOPPING ENGINE

"Do not stop the engine immediately after hard or extended driving. Keep
engine running at increased idle for about two minutes to prevent excessive
heat build-up."

> Do you drive 70+ on the
> >highway with the AC on then pull into a rest area and instantly turn off
> >the engine?
> >

Tim