What is the Bypass-Relief-Valve and Why is it Important?

Oil filters are a key part in the engine lubrication system. They remove contaminants which could cause long-term damage to your engine.
Clean motor oil is crucial to the health of the engine and if left unfiltered, it could become saturated with tiny, hard particles that can wear surfaces of internal parts.
All modern oil filtration systems include a Bypass-Relief-Valve (BPRV), which is designed to prevent “oil starvation” if and when the filter gets clogged. There are two types of filters, a spin filter where the valve is an integral part of the filter itself, and a cartridge filter where the valve is mostly part of the housing.
The Bypass-Relief-Valve is designed with a preset opening pressure to allow free flow of oil when the filter gets clogged and the lubricant is unable to flow through the filter’s media. Without a bypass valve or if the valve doesn’t open properly, pressure could build up causing the filter to burst and the oil to leak. If the valve opens too soon or too frequently, it will cause contaminated oil to flow into the engine which can accelerate the wear of surfaces. And if the valve opens too late, the flow of oil could get obstructed, resulting in poor lubrication.
This is why the opening pressure is carefully crafted to protect the longevity of your engine.
Premium Guard filters are designed to meet the Original Equipment Manufacturers (OEM), specification in all aspects including the bypass relief valve. It’s perfectly designed to accommodate the oil flow rates in modern engines.
To put it simply, Premium Guard ensures that your engine is well protected by receiving the right amount of clean lubrication.

[michaelherrell]

Very informative. Thanks. I learned something. Good diagrams.

[timkis]

this design basically makes the filter housing a storage area for dirt until bypass, then the oil washes the previously caught dirt off the media and sends it thru the bypass valve.a dumb idea.

[NoWrRun]

They by-pass valve should be on top of the oil filter ( SOME DO ) NOT THE BOTTOM, FAIL.

[SlikLizrd]

The By-Pass Valve shown in this video is of the earlier type, which has been superceded by the more advanced valve location on the filter's INLET END, as in some Motorcraft, Wix, and NAPA oil filters.
The newer design prevents the circulating oil from scrubbing off the particles from the surface of the filter's pleats while on it's way back to the sump.