Motor oil is vital for lubricating your car’s engine, dissipating heat and ensuring optimal engine performance. However, motor oil can become thick and filled with debris over time, reducing its ability to operate. Regularly changing your oil minimizes engine component wear and extends its lifespan.
Learn everything you need for an oil change, including oil types, replacement intervals, and what to expect from an oil change process.
What is the Purpose of Motor Oil?
Motor oil, or engine oil, is one of the essential fluids a vehicle needs to function correctly, alongside fuel, coolant, and transmission fluid. The overall purpose of motor oil is to keep your engine running smoothly and optimally. Fresh, high-quality motor oil serves four primary purposes: lubrication, cleaning, heat dissipation, and corrosion protection.
Lubrication and Friction Reduction
As your engine runs, its moving parts like the pistons, crankshaft, conrods, camshaft, and valves constantly turn or rotate. The longer and faster your engine runs, the more these parts turn, generating friction and heat.
Motor oil’s most critical job is to provide your engine parts with lubrication. A layer of quality motor oil helps reduce friction, ensuring these parts are adequately protected from harmful metal-on-metal contact.
Cleaning and Removal of Contaminants
Motor oil also contains detergent and dispersant agents. These additives allow motor oil to keep the internal components of your engine clean as it runs.
As motor oil circulates through a running engine, it traps dirt, dust, combustion deposits, sludge, varnish, and other contaminants before they can wear out or damage your engine. Once circulated out of your engine, your car’s oil filter eventually captures these contaminants, ensuring they do not cycle back to the engine’s internals.
Engine Heat Dissipation
Although heat is a normal byproduct of an internal combustion engine (ICE), excess heat can damage the internal components. Motor oil helps cool your engine through its heat dissipation properties.
Motor oil is thermally conductive, meaning it is a substance that naturally conducts and transfers heat. Although its thermal conductivity is lower than engine coolant, it can absorb a part of the engine’s heat and transfer it to the oil pan, ensuring it doesn’t reach harmful temperatures over 220°F while running.
Some vehicles also feature an oil cooler, which can help dissipate the heat absorbed by engine oil and help keep your engine running at its optimal temperature.
Rust and Corrosion Protection
Although motor oil is not a rust or corrosion remover, it leaves a thin protective film on metal surfaces that can displace and prevent water from touching them, helping prevent rust formation. Most motor oils also feature anti-oxidant and acid-neutralization additives, inhibiting corrosion on these metal surfaces.
Why Does Oil Need to be Changed?
Over time, as motor oil repeatedly circulates through your engine to lubricate and clean it, it is constantly exposed to heat and contaminants. They gradually degrade and break down the motor oil’s viscosity and lubricating properties.
The older your motor oil is, the less efficient it is at lubricating and cleaning your engine. If not changed periodically, it eventually accumulates excessive deposits and contaminants and can become sludge.
Oil sludge is a harmful, gel-like substance that clogs your engine’s critical components and obstructs the flow of fresher motor oil. Sludge also acts as an insulator instead of a heat dissipator, contributing to engine overheating and accelerating internal wear and tear.
Failing to change your engine oil periodically and allowing it to become sludge exposes your vehicle to the following potential consequences:
- Severe degradation of your engine’s performance
- Engine overheating regularly
- Increased wear and tear due to friction and metal-on-metal contact
- Increased fuel consumption due to the engine not turning optimally
- Engine components seizing due to sludge blocking the flow of oil and causing oil starvation
In the worst-case scenario, failing to change your oil may result in engine parts breakage or deformation, resulting in total engine failure. Examples include bearing failure, piston ring breakage, connecting rod (conrod) failure, engine bore scoring, camshaft damage, or timing belt or chain failure.
Types of Motor Oil and Average Oil Change Intervals
Knowing everything you need for an oil change means understanding what oil type your vehicle needs and how often you should replace it. The specific oil type you need depends on your vehicle’s make, model, and manufacturer recommendations.
Conventional Motor Oil
Most motor oil brands are what mechanics and auto industry specialists call conventional motor oil. It is also known as mineral oil due to its primary ingredient: refined crude oil. After refining, crude oil is mixed with various additives, creating a substance that lubricates engine components and protects them from sludge formation and corrosion.
Conventional motor oil is primarily used in passenger cars, SUVs, and light trucks with gasoline-powered engines. It is recommended on older, used vehicles, especially those produced before synthetic oils were commonly used or recommended in cars and trucks.
On average, a conventional motor oil vehicle requires an oil change every 3,000 to 5,000 miles or every 3 months. Plan for more frequent oil changes if you primarily drive in urban environments with frequent stop-and-go driving. To avoid overly frequent oil changes, avoid pushing your engine too hard, accelerate slowly and smoothly, and maintain moderate speeds.
Diesel Motor Oil
Compared to a traditional gasoline engine, diesel engines use different fuel and ignition systems and operate at higher temperatures. Consequently, they must use motor oil formulated explicitly for diesel engines.
Whether you have a car, SUV, truck, RV, van, or another vehicle, if it has a diesel engine, you must use diesel-specific engine oil. Many larger commercial vehicles also use diesel engine oil, including buses, tractors, construction machines, and semi-trucks.
A diesel car requires an oil change every 7,500 to 10,000 miles or every 6 to 12 months. However, your replacement intervals may be shorter if you frequently use that vehicle for towing or hauling heavy cargo. Consider an oil change every 5,000 to 7,000 miles if you regularly tow loads with your car.
If you frequently use your vehicle for towing, such as for a vehicle towing service, you may need even more frequent oil changes; every 3,000 to 5,000 miles.
Synthetic Motor Oil
Synthetic motor oil is a type of motor oil that was artificially created using chemical compounds instead of refining naturally occurring crude oil. Fully synthetic motor oil, also known as full-synthetic, refers to motor oil that is 100% produced using chemically synthesized molecules. This type of motor oil contains no petroleum-based compounds, making it more environmentally friendly and decreasing dependence on oil extraction and refining.
The primary benefit of synthetic motor oil is longevity. According to a 2017 AAA study, synthetic oils are, on average, 47% more efficient than conventional motor oil. They maintain their chemical structure more often, making them less likely to oxidize or acidify. This also prevents them from prematurely breaking down or degrading too quickly.
The increased efficiency allows synthetic motor oil to last longer, increasing the time or distance between oil changes. A car using full-synthetic oil can last between 10,000 and 15,000 miles under normal driving conditions, equivalent to 6 to 12 months.
Although full-synthetic motor oil has many benefits, check the owner’s manual or contact your vehicle’s manufacturer before using it in your car. Not all vehicles are compatible with synthetic motor oil. If your vehicle is compatible with synthetic oil, always use the correct grade or rating for optimum performance.
Semi-Synthetic Motor Oil
Semi-synthetic motor oil, also known as synthetic blend motor oil, is a mixture of conventional and synthetic oil. Although the ratios vary from manufacturer to manufacturer, most brands are mixtures containing 10% to 25% synthetic oil.
Semi-synthetic oil aims to provide the best of regular conventional motor oil and full-synthetic. Theoretically, the conventional oil contents are sufficient to remain compatible with engines designed to use conventional oil only while benefiting from the added longevity and extra mileage of full-synthetic.
Although semi-synthetic motor oil doesn’t have the same longevity as full-synthetic, you can expect 5,000 miles between oil changes on average, placing it between conventional and full-synthetic.
High-Mileage Motor Oil
Some motor oil brands feature additives specifically formulated to maximize the longevity of an older, high-mileage engine. These brands are known as high-mileage (HM) motor oil.
High-mileage motor oil typically features a more viscous formula and extra additives. These properties are designed to preserve a worn engine’s life or compensate for its existing wear and tear, providing optimum lubrication for older and worn-out internal components. The higher viscosity can also help achieve a better seal, filling in the pits and imperfections caused by wear and tear and reducing the risk of leaking.
Although there are no definitive rules regarding when you should start using high-mileage motor oil, it is recommended to switch to high-mileage oil if your engine hits the 100,000-mile mark. As with other mileage recommendations, your driving habits and your car’s maintenance schedule may influence when to switch to high-mileage oil.
While the frequency of oil changes with high-mileage formulations varies depending on the manufacturer, it is similar to those of conventional motor oil. Plan oil changes every 3,000 to 5,000 miles, and adjust according to your driving habits and your engine’s wear and tear.
How to Read Motor Oil Ratings
Motor oil typically features a rating called a viscosity number or viscosity grade. It consists of two elements: a number followed by the letter W and a second number. Some brands include a dash to separate the numbers. Common ratings include 5W-30, 10W-30, and 15W-40
- The first number refers to its viscosity at low engine temperatures or under cold environments. W indicates “Winter.”
- The second number refers to its viscosity at normal engine temperatures.
The number rating indicates the oil’s viscosity. Low numbers indicate thinner, better-flowing oils, whereas high numbers have thicker formulas. Engine oil naturally thickens when cool and becomes thinner as it absorbs heat. So, you must match your oil’s viscosity rating with your engine’s typical operating temperatures and environment.
For instance, lower-viscosity oils offer better protection in engines operating in cold or freezing environments. High-viscosity oils are recommended for engines that typically run hot or in hot climates.
If you’re unsure which motor oil rating your car needs, follow your manufacturer’s recommendations and use the ratings in your owner’s manual.
Full-Service Motor Oil Change, Step-by-Step
When scheduling a full-service oil change, a qualified auto technician will review everything you need for an oil change. They will ensure your vehicle receives new, fresh oil of the correct type.
Full-service oil changes include additional inspections and services to ensure your engine runs smoothly. Below is a step-by-step explanation of each step involved in a full-service motor oil change.
- Initial inspection: A qualified auto mechanic will verify your car’s current oil levels, assessing the remaining quantity and condition.
- Oil draining: After inspecting your oil, a qualified mechanic will access the vehicle’s underside and drain the oil from your vehicle’s oil pan. Your vehicle may be placed on a lift or over the channel of an inspection station, giving the mechanic access to your oil pan.
- Oil filter inspection and replacement: Once your old oil has been drained, the mechanic will locate and inspect your oil filter. If they determine it needs a replacement, they will remove it from your car and install a fresh one. It is generally recommended to change the oil filter every two oil changes.
- New oil: The mechanic will then insert the fresh oil to replace the old oil that was cycled out. If you’re not sure which oil your vehicle needs, the mechanic may provide recommendations suitable for your make and model.
- Fluid top-up: After refreshing your vehicle’s oil, your mechanic may also check and top-up other critical auto fluids, such as your transmission fluid, differential fluid, or transfer case fluids.
- Other services: Some full-service oil changes also include complimentary auto services not related to the car’s fluids, such as lubricating the car’s fittings, checking and replacing the air filter, inspecting belts and hoses, or a free tire pressure check.
- Final inspection: Once all services have been performed, a qualified auto mechanic will perform a final inspection to ensure no issues remain.
Schedule a Full-Service Oil Change at Hometown Chrysler Dodge Jeep Ram
Hometown Chrysler Dodge Jeep Ram is more than an auto dealership. We provide a full range of automotive services to ensure your vehicle receives the care and maintenance it needs, regardless of its make and model.
Shop our parts and accessories department and find authentic, high-quality Mopar parts for your Chrysler, Dodge, FIAT, Jeep, RAM, or SRT vehicle. Alternatively, contact our service department to schedule one of our professional auto services for your vehicle, including everything you need for an oil change.
We regularly offer specials on repairs and replacements, ensuring your vehicle receives maintenance, tune-ups, or repairs at the best prices.
