Understanding oil oxidation: why engine oil thickens over time
Engine oil does much more than lubricate moving parts. It helps protect the engine against wear, keeps components cleaner and supports efficient performance. Over time, however, engine oil naturally changes. One of the key reasons is oxidation.
Oxidation occurs when oil molecules react with oxygen. This process can create acidic compounds, deposits, sludge and varnish inside the engine. As these by-products build up, the oil gradually loses some of its original performance.
One visible result of this process is thickening. When oil becomes more viscous, it flows more slowly through the engine. This can make it harder for the oil to quickly reach critical areas, especially during cold starts or demanding driving conditions.
Why thickened oil is a problem
Oil that has thickened due to oxidation may no longer protect the engine as effectively. Reduced flow can increase wear, reduce lubrication efficiency and may even contribute to higher fuel consumption.
High temperatures
Heat accelerates oxidation. Engines that regularly operate under high temperatures place extra stress on the oil.
Long drain intervals
The longer oil remains in service, the more time oxidation has to develop and affect oil performance.
Stop-start driving
Frequent short trips and repeated heating and cooling cycles can place additional pressure on the lubricant.
What can speed up oil oxidation?
Several factors can accelerate oxidation. Besides heat and extended oil change intervals, contamination can also play an important role. Dirt, fuel residues, soot or small metal particles may encourage the formation of sludge and deposits.
Lower-quality oils can also degrade more quickly, especially when they do not contain a robust additive system. That is why choosing the correct engine oil is not only about viscosity grade, but also about quality, approvals and suitability for the vehicle.
How Texaco engine oils can help
Texaco engine oils are formulated to help support engine protection, viscosity stability and reliable performance over time. High-quality antioxidant additives help slow down oxidation and keep the oil performing as intended for longer.
For the best result, always follow the vehicle manufacturer’s recommendation for the correct oil specification, viscosity grade and oil change interval. In demanding operating conditions, shorter intervals may be advisable.
Need advice on the right engine oil?
Our team can help you select the correct Texaco lubricant for your vehicle, workshop or fleet.
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