Description:
6 min
Engine Oil Change Intervals
Content:
1. Optimal interval for engine oil change
1. Manual
2. Consequences of delayed oil change
3. Severe operating conditions
Optimal interval for engine oil change:
Manual
Let's take the manufacturer's recommended mileage for oil change as a benchmark and make adjustments based on operating conditions.
The manual or service bulletin specifies the recommended oil change interval. The manufacturer indicates the interval for changing the motor oil in kilometers or miles. There are also time restrictions, such as 3 months, 6 months, or 1 year. Even if the car remains parked throughout the winter and does not go on the roads, the oil in the engine will still lose its initial properties. That is why manufacturers have introduced time limits.
Recently, manufacturers have started increasing the intervals between oil changes. In pursuit of cost savings and environmental considerations imposed by legislation in certain countries, oil change intervals have noticeably increased to 12,000 ml (20,000 km), 18,000 ml (30,000 km), and so on. Extended oil change intervals are applicable to countries with a mild climate, good fuel quality, clean roads, high-quality oils, and timely maintenance. However, in severe operating conditions, such prolonged intervals can lead to premature aging of the motor oil and engine wear!
Operating Hours
Oil change based on engine operating hours is also a factor. For example, the vehicle's manual may specify changing the oil no less than every 6,000 ml (10,000 km). At an average speed of 25ml/h (40 km/h), this corresponds to 250 operating hours. If we take this value as a reference, even at a lower average speed, the oil can be changed after the same 250 operating hours, although the mileage will be lower.
The vast majority of modern cars do not have an operating hour counter. Although for the lifespan of the motor oil, it is important to consider operating hours rather than just mileage (as with transmission components). Only in some car models is the oil changed based on an internal counter, which sometimes takes into account not only the mileage but also the engine operating hours (in most cases, this counter is linked to the odometer and serves as a simple reminder). After an oil change, the service interval is reset.
On-board Computer
In relatively new vehicles, there is a special indicator that reminds the driver of the need for an oil change. In simpler models, this is a hint indicator that relieves the driver of the responsibility to remember the intervals between maintenance. In modern and more technologically advanced cars, the oil aging counter also affects the engine control unit (ECU) operation. On old oil that has clearly exceeded its lifespan, the ECU may restrict certain engine operating modes if the service interval is not reset. Thus, the ECU protects the engine from damage.
In such vehicles, the service interval (mileage until the next maintenance) is calculated based on the distance traveled over a specific period of time, fuel consumption during that period, and temperature changes during the same period. Data is collected from various sensors in the car, such as the crankshaft position sensor, oil temperature sensor, mileage from the odometer, fuel consumption, etc. Based on this data, the control unit calculates the remaining mileage until the next maintenance and displays the required service interval on the dashboard.
Operating Conditions
In general, motor oil is a patient product. If you provide it with ideal conditions - a clean, brand-new engine, moderate RPM, low loads (meaning operation without overheating), it will last longer than what smart books say. But paradise is where we are not. In real life, oil starts aging literally from the moment it moves from a sealed canister into the engine's labyrinth. Oxidation begins, accelerated by constant heating and cooling, detergent additives diminish, and dirt accumulates. There's nothing surprising about all this: oil is not only responsible for lubricating and cooling but also for cleaning the engine and removing various impurities from it. However, it's quite obvious that the rate of motor oil aging strongly depends on the conditions of its operation.
Consequences of Untimely Oil Change
1. Contamination of engine components with sludge. Towards the end of its service life, oil loses its cleaning and dispersing properties. Engine parts begin to get contaminated with fuel and lubricant breakdown products.
2. Power loss. Due to a decrease in lubricating properties, the friction coefficient increases in moving connections.
3. Slight increase in fuel consumption (as a result of the previous point).
4. Decrease in engine lifespan.
Heavy Operating Conditions
1. Fuel quality. Fuel cannot burn completely. During fuel combustion in the engine, combustion by-products such as ash, soot, resin, and sulfur are formed. Deposits such as carbon deposits, sludge, and varnish are formed on the internal walls of the engine. The worse the fuel quality, the more deposits and undesirable combustion products are generated. This is why motor oil reaches its limit faster! Only frequent oil changes help remove unwanted products from the engine, neutralize sulfur from burnt fuel, and slow down oxidation processes.
2. Short trips, urban driving. During short trips over short distances, the engine doesn't have enough time to warm up. The motor oil doesn't reach its operating temperature. Additives that neutralize fuel combustion products work slower due to the delayed chemical processes in the cold engine. Low-temperature deposits are formed, clogging the filtering elements and impairing oil circulation in the lubrication system. Operating the engine in a "start-drive for 1,5 ml (3 km) shut off" mode leads to the condensation formed on the internal walls transforming into water. Water in the oil leads to oil dilution, premature "aging" of the motor oil.
Why is such driving harmful to the oil? Well, practically for everything! In the crankcase, it starts deteriorating intensively due to contact with unburned fuel and crankcase gases that have penetrated there. As a result, the oil temperature will rise due to the lack of cooling airflow, accelerating oxidation. Increased contamination of the oil is ensured due to the inevitable growth of low-temperature deposits. And since lubrication conditions in the cylinder-piston group deteriorate at low rotational speeds (low linear displacement speed, no oil wedge, increased wear), all wear products will inevitably end up in the oil in one concentration or another. Iron, aluminum, chromium...
3. Dusty roads or roads treated with anti-icing agents. The air filter does not capture all dust particles - a small amount still enters the engine. It is also not uncommon for unfiltered air to enter the engine, especially when towing a trailer at high speeds on a highway - resulting in a very harsh operating mode. High air temperature also accelerates oxidation processes in the engine and affects the oil's lifespan. Operating the engine at low temperatures also affects the service life of the motor oil!
4. Towing a trailer, carrying heavy loads in the trunk, driving in mountainous areas. It is no secret that in heavily loaded machinery, oil reaches its limit much faster. The more the engine is loaded, the faster the oil and the engine wear out. Operating a vehicle in mountainous areas, with frequent uphill and downhill drives, also significantly affects the reduction of motor oil's lifespan.
Conclusion:
1. Refer to the manual.
2. Determine the operating conditions.
3. Choose the appropriate engine oil.
4. Pay attention to the engine's operating RPM.
5. Frequent oil change intervals - every 3,000 ml (5,000 km) - will protect you from the accumulation of deposits in the engine, the negative effects of poor-quality fuel, harsh operating conditions, etc. Shortened oil change intervals are one of the most effective ways to keep the engine in excellent condition! With oil change intervals of 3,000 ml (5,000 km), the vehicle's engine will serve faithfully for many years!