Prefill Your Oil Filter to Reduce Engine Wear

Why it’s a good idea to prefill your oil filter before installation

When you install a dry oil filter, it takes a longer than the typical few seconds for the engine to reach minimum oil pump. During that time it’s running with little-to-no pressure and that causes needless wear. However, if you prefill your oil filter, you’ll have almost no lag time when you start it up.

A few seconds more of dry starting really is a big deal

Engine lubrication systems don’t contain a check valve to retain oil pressure like the fuel system does. So residual oil pressure drains down to 0 once the engine is shut off. Then, on startup, it takes about 2-3 seconds build enough oil pressure (around 7-1o-pis) to turn off the oil light. Studies show that most engine wear occurs at startup simply because the engine is running with little-to-no oil pressure during that time.

However, if you don’t prefill your oil filter, you extend the dry running time to as long as 10-seconds because the oil pump has to fill the filter before it can build pressure. The wear that occurs during that extended dry run period is completely avoidable if you install a filled filter.

So what’s really at stake here? Well, the studies show that a quick 5-second dry start may only lightly scuff and polish metal bearing/journal surfaces. But longer periods of dry running can generate enough heat and friction to remove measurable amounts of material from cam lobes and bearings, and that reduces the engine’s overall service lifespan over time.

Here’s the least-messy way to prefilling your filter

Leave the new oil filter in the box. Then slowly fill it with fresh oil. As you reach the top slow down and allow a small bit of oil to accumulate around the mounting plate. Use this oil to lubricate the O-ring seal. Then lift the filter out of the box, leaving any spill to be captured by the cardboard.

How to pre-fill a sideways or upside down oil filter

On these filters, you can only soak the media rather than trying to fill the entire filter

1) Fill the oil filter about half full and wait until the oil soaks into the media.

2) Turn the filter sideways and roll it around until the excess oil soaks into the top portion of the filter media.

©, 2022 Rick Muscoplat