Follow the ‘4-20 Rule’ To Cool Cars Quickly.

Follow the ‘4-20 Rule’ To Cool Cars Quickly: The Daily Record says North America is bracing for another day of record breaking heat. Car experts say if drivers want to cool their vehicles quickly they should follow the ‘4-20 Rule’.   It involves opening all four windows and driving for 20 seconds. Then, close the windows and turn on the air conditioning.   This helps hot air leave faster and can save fuel.