Does Not Changing Engine Oil Increase Fuel Consumption?

[DelBentley]

Not changing engine oil can increase fuel consumption. Below are the specific functions of engine oil: 1. Shock absorption and cushioning: When the pressure at the engine cylinder port rises sharply, it suddenly increases the load on the piston, piston chips, connecting rod, and crankshaft bearings. This load is transmitted and lubricated through the bearings, providing a cushioning effect against the impact load. 2. Rust and corrosion prevention: The lubricating oil adheres to the surface of parts, preventing contact with water, air, acidic substances, and harmful gases. 3. Lubrication and wear reduction: There is rapid relative sliding between the piston and cylinder, as well as between the main shaft and bearing shells. To prevent excessive wear, an oil film of sufficient thickness must be established between the two sliding surfaces, separating the relatively sliding parts to reduce wear. 4. Cooling: Engine oil carries heat back to the oil tank and dissipates it into the air, helping the radiator cool the engine.

[Briella]

I once forgot to change the engine oil when driving, and later found that the fuel consumption did increase significantly. Because the old oil becomes thick and dirty, the lubrication effect is greatly reduced, and the friction between various engine parts increases, just like rusty gears that can't turn, the car has to consume more fuel to run. Moreover, the impurities in the oil can clog the oil passages, making lubrication even worse. What's worse, long-term failure to change the oil will accelerate engine wear, and repairs can be much more expensive than an oil change. Now I strictly follow the maintenance manual, after all, the money saved from not changing the oil isn't enough to cover the extra fuel costs, and it could also damage the car.

[AubreyLynn]

If the engine oil hasn't been changed for too long, fuel consumption will definitely increase. The principle is simple: engine oil is like the blood of the engine. Over time, it oxidizes and deteriorates, its viscosity changes, and its lubrication performance drops sharply. At this point, the friction resistance of core components like piston rings and crankshafts increases, forcing the engine to consume more gasoline to maintain power. Once, I delayed my maintenance by two months, and my fuel consumption increased by half a liter per 100 kilometers. Additionally, degraded oil loses its cleaning ability, and sludge and carbon deposits reduce the engine's efficiency. It's best to follow the manufacturer's recommended oil change intervals to avoid major losses for minor savings.

[CharlesDella]

Using oil beyond its service life can indeed increase fuel consumption. Fresh engine oil forms a uniform oil film to reduce friction, but as it ages, the additives deplete and the oil film breaks down, causing direct metal-to-metal contact. The engine has to work harder, like walking on sandy ground, leading to increased fuel injection. I once delayed maintenance on a car due to a business trip, and the fuel consumption gauge showed a 7% increase. Moreover, old oil can turn acidic, corroding engine components, and carbon deposits can obstruct heat dissipation, further increasing energy consumption. It's essential to change the oil every 5,000 kilometers, especially for vehicles frequently driven at high speeds.

[DeMolly]

Skipping oil changes inevitably increases fuel consumption, just like making an engine run in worn-out shoes. When engine oil deteriorates, its lubricating ability decreases, causing cylinder friction resistance to rise by over 20%. I remember once when I was away on business for three months without maintenance—upon returning, I noticed louder engine noise and the displayed fuel consumption jumped from 8L to 9.5L. The mechanic diagnosed that degraded oil viscosity overloaded the oil pump, forcing extra fuel to overcome friction. Old oil also tends to carbonize under high temperatures, forming sludge, all of which eats into your fuel budget.

[LeWalker]

Long-term failure to change engine oil will definitely increase fuel consumption. Fresh engine oil forms a protective film on metal surfaces, but once the oil deteriorates, this film disappears, leading to increased friction between parts and higher fuel consumption. I conducted tests on two identical car models: the one with regular maintenance consumed 8L per 100km, while the one overdue for an oil change by three months consumed 9L. Deteriorated oil also produces acidic substances that corrode oil passages, significantly increasing piston movement resistance. More seriously, sludge buildup increases internal engine resistance, indirectly raising fuel consumption. By examining the condition of old oil during maintenance, you can clearly see why fuel efficiency drops.