What are the effects of not changing car engine oil for a long time?

[HarperLee]

The effects of not changing car engine oil for a long time are: 1. It leads to the oil becoming ineffective and deteriorating, increasing wear and damage to mechanical parts; 2. The sealing effect is reduced, causing the oil to become watery and lose its sealing function; 3. The cooling effect is diminished; 4. Deposited impurities can corrode internal components; 5. The lubrication performance of bearings and the lubrication and cooling functions of mechanical transmission parts are lost, affecting the vehicle's optimal driving condition; 6. It can damage the engine; 7. Sludge may form, leading to engine failure. The method for changing car engine oil is: 1. Start the vehicle's engine to preheat it; 2. Unscrew the oil drain bolt; 3. Remove the oil filter; 4. Apply new oil to the gasket of the new oil filter; 5. Pour the new oil into the oil pan; 6. Check for leaks under the engine and inspect the oil dipstick, then start the engine for testing.