OIL FILTERS VALVES
Depending of the requirement of the filter for an engine it may contain one or a combination of filters. Here we explain the different valves their purpose and operation.
What is an anti-drain back valve?
A relief valve is located within a filter.
How it operates
• An ADV (made of Silicon or NBR) provides a seal between
the element and the inlet holes on the baseplate
• When engine is stopped: ADV is closed. Oil cannot drain
from filter.
• When engine running: Oil pressure opens ADV and oil
passes through the filter.
Purpose
• Keeps the filter full of oil when the engine is switched off.
• Ensures a quick flow of oil to engine on start up.
• Prevents oil draining out from the filter’s inlet holes.
• Stops oil from draining out of filter and oil galleries when
the engine is shut down.
Notes
• Ryco ADV’s feature a ‘cupped central section which acts
like a hinge and requires the outer circumference to stretch
to reach the open position.
• An o ring incorporated in this edge regulates the valves
to return to closed position.
• Not all filters require anti drain back valve due to the
construction of the engine.
What is a relief valve?
A relief valve is located within a filter.
How it operates
Allows oil to bypass the filter if it is blocked or if the oil is
particularly thick, which happens when an engine is cold
Purpose
• If the filter clogs, it opens up to allow unfiltered oil to bypass
the filter and ensure continued engine lubrication.
• Normally remains in the closed position because the oil flows
through the filter media and the oil is effectively filtered and
cleaned.
• Some relief valves are built into the engine block, therefore
some filters don’t contain a relief valve. Alternately some filters
may contain an up-front relief valve.
Notes
• Competitors may use small relief valves which may not allow
the correct flow of oil to the engine when the valve is activated.
OIL FILTERS VALVES
Depending of the requirement of the filter for an engine it may contain one or a combination of filters. Here we explain the different valves their purpose and operation.
What is an anti-syphon valve?
A relief valve is located within a filter.
How it operates
• Activates as a result of oil pressure change.
• Prevents oil from draining out from the filter outlet.
• Required for applications where the oil filter is mounted
in a horizontal or inverted position.
Purpose
• Prevents oil from returning to the engine when switched off.
• Located within the filter on the outlet side (downstream).
What is a by-pass valve?
This is not a filter valve and is located on the engine block.
Also referred to as a pressure regulation valve.
How it operates
• The valve will open allowing oil to flow into the engine.
Purpose
• Should the filter become blocked the valve allows oil to bypass
the filter if the filter is blocked or the oil is exceptionally thick
(high in viscosity) when cold.
• Sometimes referred to as a safety valve.
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