I called half a dozen mechanics across half a dozen states and got recommendations that ranged from 0 seconds to 10 minutes.
How often should you start your car and let it idle in cold weather
The Science Behind Winter Driving, winter auto
How often should I start my car in the cold weather? Mechanics
Idling your car in winter not worth your time or gas, driving
Are you breaking the law if you warm up your car in your state
Driving Tips for Winter in Indiana
Should You Warm up Your Engine by Letting Your Car Idle in the Winter?
Let there be heat: How long should you plug in your car, car plug
Should You Warm Up Your Car In The Winter?
Myth vs Fact: Why Idling Your Car Is A Bad Idea
How long can my car idle before I run out of gas?
Why You Shouldn't Warm Up Your Car Before Driving! - Bemac Ottawa
Warming up your car in cold weather before driving is beneficial
