Even thats a bit crazy. I get fully functioning heat from a cold engine in around 8 minutes not 8 miles. Pretty quick to warm up, mine. It’s just frustrating that it sometimes whistles when the actuators aren’t fully closed between face and feet.I don't think the heater circuit opens up fully till the engine temperature is up to operating temperature. If you have the temperature display on I can see it takes a good 8 miles to get the full operating temperature, mine is diesel,. After that my heater goes from the initial cold, then warm air to fully functioning at 8 miles. It remains fully functioning until the engine cools. That means overnight, as the engine retains heat for short stops.