Why does fuel consumption increase after an engine overhaul?

[VonBrody]

The reasons for increased fuel consumption after an engine overhaul are: New parts are precisely manufactured and tightly fitted, which increases the engine's workload and consequently fuel consumption. This is a normal situation. If the fuel consumption is only slightly higher, it's completely normal. This is because the vehicle's computer is often reset during maintenance, and the average daily fuel consumption will be reset. It should return to normal after a few days of adaptation. Other reasons for increased fuel consumption after engine repair: The viscosity of the engine oil used has increased. It's commonly known that higher viscosity engine oil is better. The function of engine oil is lubrication, and higher viscosity indicates better quality oil. However, if the oil viscosity is too high, the engine will encounter greater resistance during high-load operation, consuming more power and naturally increasing fuel consumption significantly compared to before. Lastly, another possible reason is incorrect tire pressure or improper tire size. Underinflated tires will affect fuel consumption, as lower tire pressure increases the contact area between the tire and the ground, resulting in greater driving resistance.