How to Determine the Quality of Engine Oil?

2 Answers
EmilianoMarie
07/29/25 7:49am
You can determine the quality level of engine oil from the specifications on the oil packaging. Taking "0W-40 API SN/CF" as an example, the first part "0W40" is the main grade. The smaller the number before the "W," the better the low-temperature fluidity, which provides better engine protection. "0W" indicates that the oil can be used at temperatures as low as -35°C. The number "40" after the "W" represents the viscosity index of the oil at high temperatures. The higher the number, the higher the viscosity, which also means better engine protection. Here are methods to determine the quality of engine oil: 1. Listen to the engine sound after adding oil: If, after driving a few hundred kilometers, the engine sound becomes smoother and quieter, and the vibration stabilizes, it indicates good oil quality. Conversely, if the engine sound becomes louder, duller, or the vibration increases, the oil may be problematic. 2. Observe the color and smell of the oil: High-quality oil is light in color, transparent, free of impurities, suspended particles, or sediment, and flows well when shaken. The more transparent the oil, the higher its quality. Fake oil often has a pungent smell due to inferior raw materials or processes, while genuine oil does not. 3. Observe in low temperatures: Since engine oils vary in low-temperature performance, seal a small bottle of oil and place it in a freezer set to -18°C. After 6 hours, check its fluidity. High-quality oil will flow noticeably better, indicating better engine protection in cold conditions. 4. Shake and observe: Pour the oil into a bottle and shake it vigorously until many bubbles form. Then observe how quickly the bubbles disappear. Higher-grade, better-quality oil will see bubbles dissipate faster. If bubbles persist, the oil may be problematic. 5. Check fuel consumption after adding oil: Qualified oil, due to its superior lubrication, anti-wear, and cleaning properties, reduces friction in engine components, leading to better fuel efficiency. If fuel consumption increases significantly after adding new oil, the oil may be of poor quality.
Was this review help?
19
5
Share
CamilleMarie
08/13/25 2:31am
I've been working with cars for decades, and judging the quality of engine oil requires a combination of methods. First, check the color by pulling out the dipstick—fresh oil is usually a clear amber-yellow, but if it turns dark black or cloudy, it indicates oxidation and contamination, meaning it's time for a change. The smell test is crucial: fresh oil has little to no odor, while degraded oil may carry a gasoline or burnt smell, signaling engine combustion issues. The simplest viscosity test is by hand: drip a bit of oil between your fingers and rub them together. If it feels thin like water or lacks stickiness, it means the oil has degraded and lost its lubricating properties. I also recommend using oil test strips—place a drop on the strip, and if it spreads to form a clear ring, the oil is still good; a blurry or heavily spread pattern indicates severe contamination and the need for replacement. Mileage and time are key: conventional mineral oil should be changed every 5,000 to 8,000 kilometers, while synthetic oil can last up to 12,000 kilometers. However, if you frequently drive in high-temperature areas or take many short trips, the oil degrades faster. Engine performance also gives signals: sudden increases in noise, rough starts, or noticeably higher fuel consumption may all point to degraded oil. Regular checks and maintenance ensure your engine runs smoothly for years to come.
Was this review help?
5
1
Share
Expand All
More Forum Discussions

Can the air conditioning be turned on when a new energy vehicle is turned off?

New energy vehicles can turn on the air conditioning after being turned off. However, there is no cooling function, and prolonged use can easily lead to battery drain. Therefore, it is not recommended to keep the air conditioning on for a long time while the vehicle is turned off. If you need to ventilate, you should switch to the external circulation mode to allow fresh air to enter the car. Common misconceptions about using car air conditioning: 1. Smoking in the car with the air conditioning on: Some people turn on the air conditioning and smoke in the car while resting or waiting, which is harmful to the health of the occupants because the doors and windows are closed, and the smoke cannot escape, naturally irritating the eyes and respiratory system. Therefore, turning on the air conditioning while parked is harmful in itself, and if you must smoke in the car, be sure to adjust the air conditioning ventilation control to the "exhaust" position. 2. Always using the internal circulation mode: Some car owners keep the air conditioning switch in the internal circulation position, which is not ideal. The air conditioning mode should be adjusted according to temperature and environment. The internal circulation system can be used, but not for extended periods. When the air conditioning is first turned on, it's best to use the external circulation mode first and then switch to internal circulation after the temperature drops. 3. Arbitrarily choosing the air conditioning temperature: Car owners often select different temperatures "to stay cool," but when the indoor temperature remains too low for a long time, the body's endocrine system may struggle to adjust, leading to illness. Setting the indoor temperature below 20°C can cause various discomforts.
12
1
Share

What Causes Soft Brakes in a Car?

Brake softness can be attributed to the following reasons: 1. Poor performance of brake fluid, resulting in insufficient friction between the brake pads and brake discs. 2. Over time, moisture can seep into the system. After the moisture evaporates, a certain amount of air gap forms between the brake pads and brake discs, leading to the phenomenon of soft and ineffective brakes. Self-adjustment methods for soft brakes: 1. Start the car and wait for the idle speed to stabilize (approximately 2-3 minutes). 2. Press the brake pedal firmly all the way down, applying strong force. 3. After two seconds, pull up the handbrake while keeping the foot brake pressed firmly for several seconds. 4. Then slowly release the foot brake and finally release the handbrake to complete the adjustment.
14
5
Share

Where is the Start Button in the Panamera?

The start button in the Panamera is located on the left side of the driver's seat, where you can open the electronic screen and press it twice. Below is an introduction about the Panamera: 1. The Panamera is a large coupe produced by Porsche. In terms of power, it offers a choice between a 2.9-liter V6 twin-turbocharged engine and a 4.0-liter V8 twin-turbocharged engine. 2. The cabin is centered around four sport bucket seats, ensuring that every passenger in the Porsche Panamera can experience the brand's strong sports car heritage. 3. Like other top luxury brands that offer personalized customization, the Porsche Panamera provides a wide range of interior decoration options to create unique cabin styles. These include four sets of two-tone leather combinations and seven interior trim choices, such as carbon fiber and olive wood grain panels, offering up to 13 customizable cabin leather and trim combinations.
5
1
Share

What brand is the car with a bull logo?

The bull logo represents the Italian luxury car brand Lamborghini. Below is a detailed introduction to Lamborghini: 1. The full English name of Lamborghini is Automobili Lamborghini S.p.A. It is one of the world's top sports car manufacturers and a symbol of European luxury, founded in 1963 by Ferruccio Lamborghini. 2. The golden charging bull at the front of the car is Lamborghini's iconic emblem. This muscular bull, depicted in an aggressive stance, perfectly embodies the power and unyielding personality of Lamborghini's sports cars. 3. In Italy and around the world, Lamborghini has consistently introduced astonishing supercars that are rare works of art. The brand's designs, crafted by Italy's most prestigious designer, Gandini, reflect a lifetime of dedication. Every angle and line is meticulously perfected, silently conveying Lamborghini's almost primal beauty. With its domineering appearance, Lamborghini consistently integrates extreme speed with stylish design, continuously innovating and seeking new breakthroughs for the brand.
5
0
Share

What materials are used in Tesla batteries?

Tesla models currently use NCA (Nickel Cobalt Aluminum) type batteries. Here is an introduction to Tesla batteries: 1. The common ratio of nickel, cobalt, and aluminum in NCA batteries is 8:1.5:0.5. The aluminum content is very low, making it close to a binary material. Aluminum (a transition metal) replaces manganese, modifying lithium nickel cobalt manganese oxide through ion doping and surface coating. Ion doping enhances material stability and improves cycle performance. However, during production, because aluminum is an amphoteric metal that is difficult to precipitate, the manufacturing process of NCA materials presents challenges. Nickel-cobalt-aluminum batteries require high manufacturing precision and are costly, but aluminum helps improve the chemical stability of battery cycles. 2. Within the ternary system, nickel content can be increased to achieve higher battery energy density. However, the nickel-cobalt-aluminum crystal structure is less stable than nickel-cobalt-manganese, making it prone to collapse at high temperatures, leading to thermal runaway. Additionally, excessively high pH levels can cause cell swelling, posing risks. Overall, Tesla's ternary lithium batteries are currently popular, with most pure electric vehicles using them. Lithium batteries are lighter and have higher energy density, making them highly suitable for pure electric vehicles.
16
5
Share

How to Check Tire Pressure on Trumpchi GS4?

Trumpchi GS4's tire pressure monitoring can be viewed on the dashboard. The vehicle comes equipped with a tire pressure monitoring system that provides automatic alarm alerts, requiring no manual operation. Normal tire pressure range: According to the international GBT2978-2008 standard, the standard tire pressure is 2.4-2.5bar. Methods for adjusting tire pressure: When the vehicle is unloaded or partially loaded, it is advisable to adjust the tire pressure to the lower limit of the standard value. When the vehicle is fully loaded, the tire pressure should be adjusted to the upper limit of the standard value. For new tires, the tire pressure should be increased by approximately 0.2bar above the standard tire pressure. For old tires, the tire pressure should be appropriately reduced according to the standard; if the wear is severe, adjust to the lower limit of the standard tire pressure. For comfort-oriented soft tires, the standard tire pressure can be increased by about 0.2bar. For performance-oriented hard tires, adjust to the lower limit of the standard tire pressure.
9
2
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.