MLX90614 - non-contact temperature sensor

I am interested in using the MLX90614 non-contact temperature sensor to determine if a car has pulled into my garage. My assumption is that it can detect a heat source (the engine) that is easily above 100F. However, that depends on its range. My question is - how close does the car have to be before the sensor picks up heat from the engine? Note: I do not care what the actual temperature is. I only want to distinguish between it and any other warm object like a human. Thank you.