What Types Of Engine Oil Is Used In Semi Trucks?

Interior,of,modern,semi,truck,interior,cabin,with,electronic,logWhen it comes to maintaining the performance and longevity of a semi truck, choosing the right engine oil is of utmost importance. The engine oil you select will determine how well your engine performs, how efficiently it runs, and how well it is protected against wear and tear. To help you make an informed decision, let’s explore the different types of engine oil used in semi trucks and their specific applications.

1. Conventional Engine Oil

Conventional engine oil, also known as mineral oil, is the most basic and traditional type of oil used in semi trucks. It is derived from crude oil through a refining process. Conventional engine oil provides lubrication and helps to reduce friction between various engine components. However, it has limitations when it comes to high temperatures, heavy loads, and extended drain intervals.

2. Synthetic Engine Oil

Synthetic engine oil is a more advanced and refined type of oil that is highly resistant to extreme temperatures and heavy loads. It is created through a process that chemically modifies the molecules of conventional oil, resulting in a more uniform and stable oil. Synthetic engine oil offers superior lubrication and reduces friction, which leads to improved fuel efficiency and increased engine performance. It also has a longer lifespan and can withstand extended drain intervals, making it a popular choice for many truck owners.

3. Semi-Synthetic Engine Oil

Semi-synthetic engine oil, also known as synthetic blend or part-synthetic oil, is a combination of synthetic and conventional engine oil. It offers some of the benefits of synthetic oil, such as improved performance and protection, while being more cost-effective compared to full synthetic oil. Semi-synthetic engine oil is a good option for those who want increased engine protection without the higher cost associated with full synthetic oil.

4. High Mileage Engine Oil

As semi trucks rack up the miles, the wear and tear on the engine increase. High mileage engine oil is specifically formulated to address the needs of older or higher mileage engines. It contains additives that help to condition engine seals, reduce oil leaks, and minimize oil consumption. High mileage engine oil also provides enhanced protection against engine wear and helps to maintain engine performance as the truck ages.

5. Multi-Viscosity Engine Oil

Multi-viscosity engine oil is designed to provide consistent performance under different temperature conditions. It has a rating system such as 10W-30 or 15W-40, where the numbers indicate the oil’s viscosity at low and high temperatures. The “W” stands for winter, indicating the oil’s low-temperature performance. Multi-viscosity engine oil is beneficial for semi trucks that operate in regions with wide temperature variations as it ensures proper lubrication and protection throughout the year.

6. Low Ash Engine Oil

Low ash engine oil is specifically designed for diesel engines equipped with diesel particulate filters (DPFs). These filters require engine oil with low ash content to prevent clogging and maintain their effectiveness. Low ash engine oil contains additives that help to reduce the formation of ash and minimize the risk of DPF blockage. If your semi truck is equipped with a DPF, it’s crucial to use low ash engine oil to ensure optimal performance and longevity of the filter.


The type of engine oil used in a semi truck plays a crucial role in maintaining its performance and extending its lifespan. While conventional engine oil is the most basic option, synthetic and semi-synthetic oils offer superior protection and performance. High mileage engine oil is beneficial for older engines, while multi-viscosity and low ash engine oils cater to specific temperature and filtration requirements. Consulting your truck’s manufacturer guidelines and considering your driving conditions will help you determine the most suitable engine oil for your semi truck’s needs. Regularly changing the engine oil, following proper maintenance procedures, and using the recommended oil will contribute to the smooth operation and longevity of your semi truck’s engine.

Need Truck and Trailer Services in Ocala, FL?

Mark had been working for a local dealership as a mechanic for many years, and had wanted a change of pace. He purchased a van and started doing mobile repair work for some local companies. Before long, Mark’s reputation as a reliable, experienced truck and trailer mechanic became well known. Our business goal is taking care of your equipment so you can get back to taking care of your business. We are a mobile truck and trailer repair service offering 24-hour emergency service. We work with two trucks and three mobile trailer repair units, along with five full-sized trailer bays and two full-sized truck bays in two separate buildings. We also have a fully equipped parts warehouse. Contact us today to learn more about what we can do for you!