49.48. Is it necessary to replace the oil filter when changing the engine oil?
UAЧи потрібно замінювати оливний фільтр під час заміни моторної оливи?
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This exam question from the Traffic Rules of Ukraine concerns the safe operation and proper technical maintenance of a vehicle. Although the replacement of oil and the filter is not directly described in the traffic rules as a separate norm, it is important for road safety that the vehicle is technically sound and does not pose risks due to engine wear or component failure during a trip.
It tests the understanding of the requirements of Section 31 of the Traffic Rules of Ukraine, Technical condition of vehicles and their equipment, as well as the driver's duties under point 2.3 (a) regarding ensuring the proper condition before departure. The key logic is as follows: the traffic rules require compliance with standards, technical operation rules, and manufacturer instructions, which almost always provide for the replacement of the oil filter together with the engine oil during scheduled maintenance.
The correct approach is to replace the filter every time after draining the oil, because it accumulates wear products and contaminants that immediately get into the new oil. In addition, a clogged filter can cause the bypass valve to open, and then the oil circulates without filtration, which accelerates engine wear. Other options are incorrect: reusing drained oil does not eliminate the need for filtration, and refusing to replace the filter during an oil change actually reduces the effectiveness of maintenance and contradicts the principle of maintaining technical soundness, which the theoretical exam checks.
Clause 2.3 (subclause "a" — driver's duties)
To ensure road safety, the driver is obliged: before departure, to check and ensure the technical serviceability and completeness of the vehicle, the correct placement and securing of cargo.
This clause in tests often "leads" to the topic of proper technical maintenance: the driver must ensure the serviceability of the vehicle, including through scheduled maintenance (but the Traffic Rules do not specify exactly how to change the oil or filter).
Clause 31.1 (section 31 "Technical condition of vehicles and their equipment")
The technical condition of vehicles and their equipment must comply with the requirements of standards related to road safety, rules of technical operation, and manufacturers' instructions.
It is the mention of "manufacturers' instructions" that is the closest Traffic Rules provision to the question of replacing the oil filter: the maintenance schedule (oil change together with the filter) is determined by the manufacturer, but the Traffic Rules do not establish a separate direct requirement to "always change the oil filter".
Conclusion regarding the compliance of the question with the Traffic Rules
The Traffic Rules of Ukraine do not have a separate clause that directly regulates the mandatory replacement of the oil filter specifically "during engine oil replacement." This issue pertains to the maintenance schedule (manufacturer's instructions) and the general obligation of the driver to maintain the vehicle in a technically sound condition (clauses 2.3 and 31.1).
Thus, the correct answer is "The oil filter must always be replaced after draining the engine oil," given that according to the Traffic Rules, the driver is obliged to ensure the technical serviceability of the vehicle and comply with the rules of technical operation and manufacturers' instructions (clause 2.3 "a", clause 31.1).
During vehicle maintenance, engine oil replacement is considered a procedure intended to ensure proper lubrication and protection of engine components. In the context of safe vehicle operation requirements, this aligns with the general principle of the Traffic Rules: the vehicle must be technically sound and must not pose a threat due to malfunctions or improper maintenance.
The oil filter is a component that traps wear products, carbon deposits, and fine metal particles that inevitably appear in the oil during engine operation. Even if you drain the old oil, contaminants remain in the filter and its housing, which mix with the new oil when the engine is started. As a result, instead of a “clean replacement,” you actually get new oil that immediately begins to be contaminated by residues from the old filter.
An important practical point: when the filter element is clogged, many filters have a bypass valve that activates, allowing oil to circulate without filtration. That means the engine continues to receive lubrication, but it passes through without proper cleaning. For example, after a typical service interval, the filter is already operating at its limit, and if it is not replaced, the risk of running “almost without a filter” becomes real, accelerating component wear.
That is why, in practice, service centers always replace the oil filter together with the oil: this is a single interconnected operation that ensures proper filtration of the new oil and reduces the risk of increased engine wear. The cost of the filter is insignificant compared to the possible consequences of circulating unfiltered oil.
Therefore, the correct answer is: “The oil filter must always be replaced after draining the engine oil,” because without replacing the filter, the new oil quickly becomes contaminated, and if the filter is clogged, oil may bypass filtration, accelerating engine wear and contradicting the principle of maintaining the vehicle’s technical soundness.