Is Thinner or Thicker Engine Oil Better?

[DiCaleb]

There is no absolute good or bad; the appropriate engine oil grade should be selected based on the vehicle model and season. Under the premise of ensuring lubrication, thinner viscosity offers better fluidity and lower resistance, while thicker viscosity results in poorer fluidity and higher resistance but provides relatively greater stability. Below are relevant details: 1. Engine Oil Selection: Generally, due to the widespread use of turbocharged engines in German cars and their technical structures, they require higher viscosity oil. In contrast, Japanese cars, with their different engine design philosophies, recommend low-viscosity, high-fluidity oil. Additionally, thicker oil provides better protection in summer, while thinner oil facilitates easier starts in winter. 2. Hazards of Incorrect Oil Viscosity: If the replaced oil viscosity is unsuitable, overly thin oil can lead to excessively low oil pressure, insufficient lubrication, increased friction between engine parts, resulting in abnormal noises and accelerated wear. If the oil is too thick, excessive resistance increases engine load, thereby raising fuel consumption. Therefore, it is best to choose the appropriate oil type and viscosity according to the vehicle model's requirements.

[CatherineFitz]

I feel whether thinner or thicker engine oil is better really depends on the specific situation. Last time when I drove an old car, I used thinner oil, the SAE 5W-30 type, and it started up really quickly in cold weather—the engine fired up as soon as I turned the key, and it was quite fuel-efficient too, with no issues even on the highway. But after switching to a new car, I changed to thicker 10W-40 oil, and when driving aggressively on the highway in summer, the engine ran quieter, had better lubrication, and offered more thermal protection, though fuel consumption was slightly higher. Actually, choosing oil viscosity depends on your driving conditions. For me, driving mostly in stop-and-go city traffic, thinner oil works well; if you frequently take long highway trips, thicker oil is more reliable. The age of the car also matters—older engines with more wear benefit from thicker oil for added protection, while newer, more precisely engineered cars suit thinner oil for better fuel efficiency. In short, don’t switch randomly—check your vehicle’s manual and use what they recommend to avoid engine wear or wasting money. Choosing the wrong oil can also lead to carbon buildup or noise issues, so regular maintenance checks are always a good idea.

[LaLane]

Let's talk about oil viscosity from a temperature perspective. Those who've driven in winter know - thinner oils like 5W flow better in cold, enabling quicker cold starts without dry engine friction. Especially below freezing, they lubricate faster and improve fuel efficiency. But in summer or high heat, thinner oils evaporate easier or provide insufficient protection, potentially causing overheating. That's when thicker oils like 10W-40 shine - their higher viscosity withstands extreme heat and high speeds, offering longer-lasting lubrication that reduces wear. Living up north, I swear by thinner oils in winter, but switch to thicker grades when traveling to hotter southern regions. Driving patterns matter too: thinner oils suit city stop-and-go traffic, while thicker ones stabilize during highway cruising. Never overlook oil grades - full synthetics handle temperature extremes best with balanced viscosity. The golden rule? Adjust according to season and driving conditions, consult professionals or your manual, and never cut corners - your engine's longevity depends on it.

[LeEvangeline]

Engine age affects oil selection. From my experience with different cars: older engines with more wear and potentially looser oil passages benefit from thicker oils like 10W-40, which can fill gaps, provide extra protection against leaks and noise. But modern high-precision engines perform better with thinner oils that flow easily, ensuring smooth cold starts and fuel efficiency. Always match the oil viscosity to your specific vehicle - don't uniformly use thin or thick oils.

[DiCassidy]

Engine oil viscosity significantly impacts fuel consumption and protection. Thin oil flows faster, reducing engine resistance and helping save about 5% to 10% fuel, especially suitable for city driving. However, it offers weaker protection and may provide insufficient lubrication at high speeds or under heavy loads. Thick oil has the opposite effect, with slightly higher fuel consumption due to greater resistance, but offers more stable protection under high temperatures and heavy loads, extending engine life. I use a balanced oil like 5W-30, which balances performance and efficiency, with minor adjustments based on driving intensity. Remember to choose the right certification, such as API SN grade, for better compatibility.

[ODerek]

I believe the choice between thin or thick engine oil requires balancing benefits. Thin oil allows for quick starts and better fuel efficiency, suitable for gentle driving; thick oil offers stronger lubrication and better high-temperature resistance, providing superior engine protection, but at the cost of slightly higher fuel consumption. Based on my experience, pay attention to the SAE viscosity grade numbers—the smaller the number before the 'W,' the thinner the oil, ideal for cold weather; larger numbers indicate thicker oil, better suited for hot weather. Driving habits are also crucial—thicker oil for aggressive driving; thinner oil for smooth commuting. Don’t forget to check the dipstick or change the oil regularly to avoid incorrect choices leading to accelerated wear or engine failure.