There is no one particular reason why oil consumption in a car increases. Sometimes it’s because of the driver’s fault and sometimes it happened as the time passes by. I can tell you some causes for oil consumption.
How do you drive? Sometimes how people drive the car affects the oil consumption. I know many people who drive on highway with low fuel in the car. This affects the oil consumption badly. So it’s really necessary to maintain the fuel in the car. Also, speedy driving or bumpy driving also affects the oil consumption.
Oil Viscosity: Some people put motor oil in their car which is not specified for their car model. So in order to save a little extra money, drivers play with the viscosity of the motor oil in their car which leads to higher oil consumption and oil leak in the engine.
Engine auto parts condition: One need to scan the engine parts in the car for any kind of leak or worn. When there is any sealer worn or if there is coolant leak, the engine sucks up motor oil like anything. So take care of that.
Car too heavy: When you have lot of passengers in your car or even too much luggage in your car, the engine takes more oil than normal to drive through.
Tire Air pressure: When the air pressure in your tires is low, that also increases the oil consumption in your car.
Regular Oil change: It’s a vital job to change the motor oil on regular interval of time in order to maintain the quality and viscosity of oil. If you skip the oil change, it becomes impure and increases the oil consumption.
I am aware of these points. Please share if you know more.