Discover the oil filter bypass valve


Oil is essential for the smooth lubrication of your engine. However, dirty oil can cause extensive and expensive damage to your engine. This means that having a working oil filter is important for maintaining the health of your engine.

An oil filter has three main tasks:

  • Remove contaminants from the oil. This includes dirt, oxidized oil and metallic particles.
  • Trap and hold these contaminants until the next oil filter change.
  • Avoid unnecessary flow resistance, allowing enough pure oil to enter the engine for optimal performance.

It’s possible to extend the lifespan of your oil filter by using high-end synthetic oil which is more refined and distilled than regular oil, so it lasts longer and has fewer contaminants. But, that’s not always enough.

The purpose of an oil filter bypass valve

Over time the filter can get clogged, which restricts oil flow. Additionally, sometimes the oil pump sends more oil to the filter than the filter can process due to demands from the engine. As it can severely damage your engine if there is no oil to lubricate all the moving parts – and even dirty, unfiltered oil is better than none – quality oil filters are equipped with a bypass valve to ensure continuous oil flow in all conditions.

Before we look at how the bypass valve works, we should start by looking at normal conditions with an operational oil filter. In this case, oil runs through the filter, which cleans it of contaminants, protecting your engine.

However, if the engine is cold or operating at high speed, there isn’t enough oil coming through the oil filter to fully lubricate the engine. In this case, oil goes through the bypass valve, ensuring that there is sufficient oil flow. By allowing the oil to bypass the filter, it means that the oil is only partly filtered.

Additionally, if the filter is clogged, the pressure spring inside the oil filter enables the oil to pass through the bypass valve without any filtration.

It’s good to note that at low speeds and when the engine is warm, the bypass valve remains closed, so only pure oil enters the engine.

Watch more with Garage Gurus

Want to know more? Watch a Garage Gurus expert as he explains more about oil filters and their bypass valves.


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