Oil Filter Drainback, Why an Issue on the V-10?
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Oil Filter Drainback, Why an Issue on the V-10?
On another thread about oil filters the comment was made:
I found this on the Fram site:
Anti-Drainback Valve. Some oil filter mountings may allow oil to drain out of the filter through the oil pump when the engine is stopped. When the engine is next started, oil must refill the filter before full oil pressure reaches the engine. The anti-drainback valve, included in the filter when required, prevents oil from draining out of the filter. This anti-drainback valve is actually a rubber flap that covers the inside of the inlet holes of the filter. When the oil pump starts pumping oil, the pressure will unseat the flap. The purpose of this valve is to keep the oil filter filled at all times, so when the engine is started there will be an almost instantaneous supply of oil to the engine.
The filter on the V-10 is mounted with the inlet/outlet on top, so how can the oil drain out of the filter? Why would the antidrainback valve be critical with this mounting?
Anti-Drainback Valve. Some oil filter mountings may allow oil to drain out of the filter through the oil pump when the engine is stopped. When the engine is next started, oil must refill the filter before full oil pressure reaches the engine. The anti-drainback valve, included in the filter when required, prevents oil from draining out of the filter. This anti-drainback valve is actually a rubber flap that covers the inside of the inlet holes of the filter. When the oil pump starts pumping oil, the pressure will unseat the flap. The purpose of this valve is to keep the oil filter filled at all times, so when the engine is started there will be an almost instantaneous supply of oil to the engine.
The filter on the V-10 is mounted with the inlet/outlet on top, so how can the oil drain out of the filter? Why would the antidrainback valve be critical with this mounting?
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It's like a siphon. The oil in the heads can actually drain back through the filter and leave air in the heads. If the filter's antidrainback valve is not there, the heads can be starved of oil when the engine is first started.
Even though the filter is vertical, the filter itself won't empty, but it will allow all the oil up in the heads to drain back down.
Even though the filter is vertical, the filter itself won't empty, but it will allow all the oil up in the heads to drain back down.
FTE Leadership Emeritus
Joined: Jul 2002
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From: Long Island USA
As a matter of fact, it can happen in any motor, not just overhead cam engines. Any oil above the filter will drain back through the filter, if it doesn't have an anti-drainback valve.
More Turbo
Joined: Mar 2005
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Same filter (FL-820S style) is used on the 4.6 and in the mustang configuration, it's mounted near 90 to the block so drain back would be a problem without the drain back valve. They make all those filters with the valve since they have no idea what you will put it on and no need to create a new part number without the vavle.
