What type of engine oil should be used for a car with 100,000 kilometers?

[KarterAnn]

For a car with 100,000 kilometers, use 5W-40 engine oil. Engine Oil: Engine oil, also known as engine lubricant (English name: Engine oil), has a density of approximately 0.91×10³ (kg/m³). It serves multiple functions for the engine, including lubrication and wear reduction, auxiliary cooling, sealing and leak prevention, rust and corrosion protection, and shock absorption. It is often referred to as the "blood" of a car. Engine oil consists of two main components: base oil and additives. The base oil is the primary constituent of the lubricant, determining its fundamental properties, while additives compensate for and enhance the base oil's performance, providing additional characteristics. Additives are a crucial part of the lubricant. Key Features of Engine Oil: The engine is the heart of a car, containing numerous metal surfaces that move against each other under high speed, harsh conditions, and temperatures ranging from 400°C to 600°C. Advanced technology can convert natural gas into crystal-clear, fully synthetic base oil, which is then combined with proprietary cleaning technology to create lubricants with superior cleaning and protective properties. Only high-quality lubricants can reduce engine component wear and extend service life under such extreme conditions. Engine oils on the market can be broadly categorized into mineral oil and synthetic oil based on their base oil (vegetable oils are not considered due to their scarcity). Synthetic oils are further divided into full synthetic and semi-synthetic. Lubricant base oils mainly fall into two categories: mineral base oil and synthetic base oil. Mineral base oils are widely used and account for the majority of the market (over 95%), but certain applications require products formulated with synthetic base oils.

[Myrtle]

My old car has already run nearly 150,000 kilometers, and over the years I've learned some tricks about oil changes. For cars with over 100,000 km, you should focus on sludge cleaning and anti-wear properties - I recommend using 5W-30 or 5W-40 full synthetic oil, and never arbitrarily switch to lower viscosity grades. Last year I tried saving money with the wrong oil, and the engine started making gurgling noises like it had phlegm stuck in it. When I opened the engine cover, it was full of sludge. Now I only buy high-mileage certified oils - not because of brand superstition, but mainly because these oils contain extra additives to prevent seal aging. You need to check the dipstick every 5,000 km - old cars especially tend to burn oil. Last month I had to top up half a liter just to make it to the next service interval. Remember to ask your mechanic to check the oil pump pressure - severely worn engines often show pressure drops.

[DiZoe]

Last week, I took my Sagitar, which has clocked 110,000 kilometers, for an oil change. Using 5W-30 full synthetic oil is definitely the right choice. The mechanic counted on his fingers while explaining: for regular cars, sticking to the viscosity grade in the maintenance manual keeps them running safely, while for older German cars, a 40 viscosity offers more peace of mind. Looking back at the photos from the last oil change saved on my phone, the drained oil was as black as soy sauce. The mechanic emphasized that frequent oil changes are crucial for high-mileage vehicles. Given the hot weather, I specifically picked an oil with strong high-temperature shear resistance, especially since the engine clearances widen in older cars. I watched as the mechanic replaced the oil filter and even swapped out the rubber gasket—these small parts are the most prone to leaks. All in all, it saved me over 200 yuan compared to the dealership, but the key is making sure you’re buying genuine products.

[VanJudah]

Having driven three cars with over 100,000 kilometers, the most profound lesson I've learned is never to compromise on engine oil. My old Nissan Sylphy ran for 200,000 kilometers using 5W-30 full synthetic oil, and even now, the engine sounds crisp during cold starts. Last year, when I had the transmission repaired, the oil pan was removed as well, and it was clean with no sludge. A friend who opted for cheaper semi-synthetic oil had his valve cover gasket leaking by 100,000 kilometers. I make it a habit to keep an extra liter of oil handy, as older cars tend to consume some oil. I always keep a dipstick in the trunk and check the oil level whenever I refuel. Some engine oils now come with metal repair additives, which can help with worn parts, but don't expect miracles.

[Josie]

What kind of car is it? Does it have a turbo? When my 2.4L Accord hit 130,000 kilometers, the mechanic demonstrated an oil film test for me. Since then, I've been using 5W-30 full synthetic oil, especially focusing on anti-wear formulas. I suggest checking the manual when you have time; it usually specifies viscosity requirements. One day, I heard metal friction sounds during cold starts, and only discovered during an oil change that the last mechanic used low-viscosity oil. Now, I always watch the oil being poured in. If there's a lot of carbon buildup on the piston tops, it's easy to get stuck rings. By the way, for cars over 100,000 kilometers, it's best to shorten the oil change interval. Last time during maintenance, the sludge cleared out almost clogged the oil filter. There are high-mileage specialty oils on the market, and the rubber softeners in them do help delay oil seal leaks.

[JacksonRose]

Having repaired over ten thousand vehicles in the workshop, the 100,000-kilometer mark is a critical milestone. Using the wrong oil is like giving someone the wrong medicine—5W-30 is the safest choice, while 40 viscosity is more reliable for German cars. I’ve seen cases where 5W-20 was mistakenly replaced with 0W-20, and the engine knocking sound was painful to hear. Always prioritize the ACEA certification number—it’s more important than API. The condition of the old oil during draining reveals the engine’s health: milky oil indicates a leaking head gasket, and metal shavings are a warning sign. We routinely use a borescope to inspect cylinder wall scratches—if scoring is found, we recommend switching to higher-viscosity oil. Don’t forget to flush the oil pan during oil changes; the scene of cleaning out half a bowl of sludge deposits last time remains unforgettable.