Does thicker oil increase oil pressure?

Maintaining proper oil pressure is crucial for the optimal performance and longevity of your vehicle’s engine. One common question among car owners is whether using thicker oil can increase oil pressure. The answer to this question involves understanding the relationship between oil viscosity, oil pressure, and engine health.

is thicker oil better for older engines

Will thicker oil increase oil pressure?

Oil viscosity refers to the thickness or resistance to flow of the oil. Thicker oil, such as SAE 50, has higher viscosity, meaning it flows more slowly than thinner oil. The oil pressure in an engine is created by the oil pump, which circulates oil through the engine to lubricate and cool its moving parts. Oil pressure is influenced by several factors, including oil viscosity, engine speed, temperature, and the condition of the oil pump and engine components.

Using thicker oil can indeed increase oil pressure. Since thicker oil flows more slowly, it can create more resistance within the oil passages, leading to higher pressure readings. This is particularly noticeable in engines with worn bearings or internal components, where the thicker oil can help maintain a more stable oil film between moving parts, preventing excessive wear.

What happens if you put thicker oil in your car?

Using thicker oil than recommended for your car can have several effects, both positive and negative, depending on various factors like engine condition, climate, and driving habits. Here is what can happen if you put thicker oil in your car:


1. Increased oil pressure: Thicker oil can create more resistance within the oil passages, leading to higher oil pressure. This can be beneficial in older engines with worn components, as it helps maintain a stable oil film between moving parts.

2. Reduced engine wear: In high-mileage engines, thicker oil can provide better lubrication and reduce the risk of metal-to-metal contact, thereby minimizing wear and tear on engine parts.

3. Better performance in hot climates: In hotter climates, thicker oil maintains its viscosity better at high temperatures, ensuring normal oil pressure, consistent lubrication and protection of engine components.


1. Poor cold-start performance: Thicker oil may not flow adequately at low temperatures, causing insufficient lubrication during startup. This can lead to increased wear and potential damage to engine components.

2. Reduced fuel efficiency: Higher viscosity oil creates more resistance, which can reduce fuel efficiency as the engine works harder to pump the oil.

3. Potential overheating: Thicker oil may not circulate as effectively, leading to hotspots and potential overheating in some areas of the engine.

4. Strain on the oil pump: The oil pump has to work harder to circulate thicker oil, which can lead to increased wear on the pump and potentially shorten its lifespan.

5. Incompatibility with modern engines: Modern engines are designed with precise tolerances and often require specific oil viscosities to operate efficiently. Using oil that is too thick can disrupt the engine’s optimal performance and may void manufacturer warranties.

Should I use thicker oil in a high mileage engine?

Is thicker oil better for older engines? Using thicker oil in a high-mileage engine can be beneficial, but it’s not a one-size-fits-all solution. High-mileage engines often have increased wear and tear, leading to larger clearances between moving parts. Thicker oil, such as 10W-30 or 10W-40, can help maintain proper lubrication by filling these gaps more effectively, reducing the likelihood of oil leaks and burning. This can improve engine performance and longevity, as well as reduce noise and wear.

However, it’s essential to consult your vehicle’s owner’s manual before making the switch. Some modern engines are designed to work best with specific oil viscosities, and using a thicker oil might not be recommended. Additionally, consider the climate in which you drive; thicker oil may not perform well in colder temperatures, potentially leading to harder starts and reduced efficiency. Always balance the benefits of thicker oil with the manufacturer’s guidelines and your driving conditions.

Will thicker oil damage my engine?

Using thicker oil can damage your engine if it does not meet the manufacturer’s specifications. Modern engines are designed with precise tolerances and often require specific oil viscosities to ensure optimal performance. Using an oil that is too thick can hinder the proper flow of oil, especially during cold starts, leading to low engine oil pressure and inadequate lubrication. This can result in increased wear and tear, reduced fuel efficiency, and potentially even engine damage over time.

However, in some cases, thicker oil might be beneficial, particularly for high-mileage or older engines with worn components. Thicker oil can provide better sealing, reduce leaks, and maintain oil pressure in such engines. The key is to balance the benefits with the potential risks. Always consult your vehicle’s owner’s manual and consider factors such as climate and driving conditions before making a switch. Adhering to the manufacturer’s recommendations will help ensure your engine remains protected and operates efficiently.


Thicker oil can increase oil pressure, but it is important to use the oil viscosity recommended by your vehicle’s manufacturer. Deviating from the recommended engine oil can lead to suboptimal engine performance and potential long-term damage. If you are experiencing low oil pressure, it is essential to diagnose the underlying cause rather than simply switching to a thicker oil. Regular maintenance, including timely oil changes and using the correct oil grade, will help ensure your engine remains in good health and operates efficiently. If you have concerns about oil pressure or oil viscosity, consult with a trusted mechanic to determine the best course of action for your specific vehicle.


Mohammad Shafiqule Islam is a seasoned mechanical engineer with over 16 years of experience in automotive maintenance and training. He combines technical expertise with a passion for the automotive industry. His extensive background includes hands-on maintenance, diagnostics, and advanced training, making him a valuable resource for industry insights and practical advice. Shafiqule's engaging writing style and deep knowledge ensure that his content is both informative and accessible, catering to professionals and car enthusiasts. His dedication to continuous learning and sharing insights helps you stay informed about the latest advancements and best practices in automotive maintenance.

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