What are the consequences of not changing engine oil regularly?

[LoganLee]

If engine oil is not changed regularly, the following situations may occur: 1. Reduced acceleration. The deterioration of engine oil can prevent the engine from operating normally, leading to reduced car acceleration. If the engine runs smoothly when the accelerator is pressed but there is no noticeable increase in speed, it may indicate that the engine oil is deteriorating. Additionally, engine noise may become louder or vibrations may increase. 2. Worsened fuel economy. When engine oil deteriorates, fuel efficiency also deteriorates. Reliable experimental tests have shown that fuel consumption significantly decreases after changing the engine oil. In some cases, switching to a suitable brand of engine oil can also improve fuel efficiency. 3. Engine aging or failure. Continued use of deteriorated engine oil can significantly increase the risk of engine component wear. The cooling function of the oil will not be fully effective, and in some cases, the engine may seize. If these conditions occur, the cost of repairs will far exceed the expense of changing the engine oil.

[LaAiden]

I've seen too many cars with ruined engines due to neglected oil changes. Over time, engine oil becomes thinner and contaminated, drastically reducing its lubricating effectiveness. This leads to metal components grinding directly against each other, and sludge buildup can clog oil passages. The most obvious symptoms are rattling noises during cold starts, sluggish acceleration, and rapidly increasing fuel consumption. Prolonged neglect causes severe wear to piston rings and cylinder walls. Burning oil and blue smoke are just the beginning – you might even need a complete engine overhaul. My neighbor's SUV, for example, skipped oil changes for 30,000 kilometers until its cylinders seized. The repair costs could've covered a decade's worth of oil changes. Always follow your maintenance manual – penny wise, pound foolish never pays off with engines.

[StGemma]

As a budget-conscious person, I've done the math: skipping oil changes to save money is absolutely a losing proposition. Old oil loses its cleaning ability, allowing carbon deposits to accumulate in the engine, reducing power and increasing fuel consumption by hundreds of dollars annually. Even worse, sludge can clog the oil filter screen, leading to insufficient lubrication. When precision components like camshafts and crankshafts wear out, repairs can cost tens of thousands. I learned this the hard way when I delayed an oil change until 12,000 km - the engine warning light came on, and upon inspection, the oil pan was filled with asphalt-like sludge. Now I change full synthetic oil every 8,000 km without fail, and after six years, my car still runs as smoothly as new.

[StephenDella]

From a physical property perspective, the viscosity index of aged engine oil plummets. At high temperatures, the oil film becomes thinner, with high-speed components like crankshaft bearings and turbochargers being the first to suffer. I've disassembled engines that went too long without oil changes - the bearing surfaces were scored, and there was carbon buildup on the turbo blades. Worse yet is the deteriorated low-temperature fluidity - during cold winter starts, metal experiences dry friction, with valve lifters being most vulnerable. Last time I helped a friend inspect his car, the oil had been used for 15,000 km with metal particulate levels seven times over the limit - any later and it would have led to bearing failure. Regular oil changes are essentially buying insurance for your engine.