This guy says pre-filling an oil filter is bad and that all manufacturers say so.

[billt460]

No it does not. Please show me any empirical DATA that states this? OR are you and engine builder by profession at any time and have tested you interesting comment because I am and have!

Come on. You don't need, "empirical data". Or need to be an, "engine builder". Common sense dictates a filter that is full of oil is not going to delay pressure, because it doesn't have to wait to be filled by the oil pump. I've done it both ways. The engine builds oil pressure much faster with a prefilled oil filter. And it doesn't matter what engine it is, or who built it.

 

[BHopkins]

Wow! A discussion on the merits of pre-filled oil filters. Sure glad to see this brought up. I don't think I've ever seen this topic discussed before here on BITOG. . At least not this week.

Actually, the video posted by the OP made me curious. So I checked the factory service manual for my Outback. I have to admit, I've never read a service manual section on engine oil or oil filter replacement. There is no mention of priming the oil filter.

 

[02SE]

Wow! A discussion on the merits of pre-filled oil filters. Sure glad to see this brought up. I don't think I've ever seen this topic discussed before here on BITOG. . At least not this week.

Actually, the video posted by the OP made me curious. So I checked the factory service manual for my Outback. I have to admit, I've never read a service manual section on engine oil or oil filter replacement. There is no mention of priming the oil filter.

Up next: How do you hold the oil bottle while pouring the oil into the oil fill hole?

 

[Oliveoil2]

Pre fill for 47yrs of mechanical experience. Might help, can’t hurt! And 10-13k oci, (synthetic) and 20-26k oci fram ultra. A second or two on a cold engine that’s not primed is not insignificant.

 

[ZeeOSix]

How long does it take after the vehicle sits overnight or longer? Do things like the pickup tube drain out, causing longer times? Just asking.

All my vehicles build oil pressure in 1-2 sec after sitting all night, so the filter ADBV is working well. If you find that your cold oil level is higher than your hot oil level, then that could mean the filter ADBV is leaking oil back to the sump over night.

 

[BHopkins]

Up next: How do you hold the oil bottle while pouring the oil into the oil fill hole?

Here are a few other ideas that we can discuss, that are based only upon BITOG excess.

• Shaking oil jugs before pouring or not?
• Store motor oil inside or in garage?

 

[spasm3]

Come on. You don't need, "empirical data". Or need to be an, "engine builder". Common sense dictates a filter that is full of oil is not going to delay pressure, because it doesn't have to wait to be filled by the oil pump. I've done it both ways. The engine builds oil pressure much faster with a prefilled oil filter. And it doesn't matter what engine it is, or who built it.

My guestion has always been ; If you don't prefill the filter, where does the air in the filter go?
Will the air being pushed out by the 40 psi oil pump, move the oil out of the holes in the crank an/ or wipe the oil off the first main bearing near the oil pump?
For the sake of discussion, as some prefill some don't , it does not seem to matter that much. I prefill.

 

[vavavroom]

Up next: How do you hold the oil bottle while pouring the oil into the oil fill hole?

I hold the bottle firmly yet carefully, spout in the position sanctioned not only by the NSPE but also by the Catholic Church.

 

[vavavroom]

My guestion has always been ; If you don't prefill the filter, where does the air in the filter go?

You just had to open this door. A few members will have at least several sleepless nights.




(The oil feed holes burp)

 

[atikovi]

My guestion has always been ; If you don't prefill the filter, where does the air in the filter go?
Will the air being pushed out by the 40 psi oil pump, move the oil out of the holes in the crank an/ or wipe the oil off the first main bearing near the oil pump?

You know how many times it takes you to wash your hands with soap and water if you get any oil on them? Then I doubt the air will wipe off the oil from the bearings.

 

[4WD]

Here are a few other ideas that we can discuss, that are based only upon BITOG excess.

• Shaking oil jugs before pouring or not?
• Store motor oil inside or in garage?

Those are great September previews … can we add my stash is bigger than yours ?

 

[gregk24]

I used to pre-fill, now I just inspect the filter and lube the o-ring before install. I have noticed no difference in sound or the time it takes oil pressure to build.

 

[billt460]

My guestion has always been ; If you don't prefill the filter, where does the air in the filter go?
Will the air being pushed out by the 40 psi oil pump, move the oil out of the holes in the crank an/ or wipe the oil off the first main bearing near the oil pump?
For the sake of discussion, as some prefill some don't , it does not seem to matter that much. I prefill.

I agree. It's not a life or death procedure for your engine. But it's easy to do, takes no tools, along with very little time or effort to accomplish, and it cuts the lack of oil pressure running time by about half, (as Zee O Six has posted), and I concur with his assessment. And as you just mentioned, anytime you can eliminate air from your lubrication system in favor of oil, it's a good thing.

 

[Accent Abuser]

This is the part I'm not getting. Where is the added "danger" in prefilling a filter from a "unfiltered" jug of oil, as opposed to pouring the contents of that same jug into the oil fill hole in the engine? It's not like these filter companies ship out their filters packed full of crap. If a filter is brand new, both sides of the media are "clean".

I always turn the filter upside down, and rap the gasket end against a hard surface before filling and installing it. (Something I can all but guarantee you no franchise oil change outfit ever does). In over 50 years, I've never had anything fall out. And it's not as if anyone changes oil in a NASA certified clean room.

Any oil dumped into the engine gets to the sump via the comparatively large drain holes, oil is then sucked up via the pickup tube and before it gets to all those important bits with extremely small clearances, it's pumped through the filter.

Theoretically you could pour a small particle into the clean side (ie a tiny piece of seal material)q, which would be immediately pumped through the bearings, at best, scratching them and at worst, clogging an oil passage causing oil starvation.

Most modern filters are very small, mine don't even hold 1/4 of a quart, oil is pumped very fast through an engine. The time without oil saved by filling the filter may be measured in 10ths of a second. Not enough time for me to even notice a difference as far as how long it takes for the oil pressure light to go out. Even without prefilling it's so quick if you blink you'll miss it.

 

[billt460]

Any oil dumped into the engine gets to the sump via the comparatively large drain holes, oil is then sucked up via the pickup tube and before it gets to all those important bits with extremely small clearances, it's pumped through the filter.

Theoretically you could pour a small particle into the clean side (ie a tiny piece of seal material)q, which would be immediately pumped through the bearings, at best, scratching them and at worst, clogging an oil passage causing oil starvation.

Possible, but highly unlikely. Certainly not enough to worry about. Especially when you consider you're filling the filter with oil poured from the top of the jug. IF there are any contaminates in that jug, they'll be at or near the bottom. Not floating at the top. And I've never "shaken" oil before pouring the entire container into the engine. If the engine doesn't mix it, I don't know what will.

 

[Accent Abuser]

Possible, but highly unlikely. Certainly not enough to worry about. Especially when you consider you're filling the filter with oil poured from the top of the jug. IF there are any contaminates in that jug, they'll be at or near the bottom. Not floating at the top. And I've never "shaken" oil before pouring the entire container into the engine. If the engine doesn't mix it, I don't know what will.

Yes, highly unlikely, but not impossible and it has happened before. For the person changing their own oil at a leisurely pace, it's very unlikely. For mechanic changing oil on multiple cars for a living, or a fleet mechanic servicing an entire fleet, it invites the potential for mistakes.

In professional situations where a pump is used, it's also more risky. The end of the nozzle could be dirty, or could've picked up junk from another persons fill hole etc.

 

[atikovi]

Here are a few other ideas that we can discuss, that are based only upon BITOG excess.

• Shaking oil jugs before pouring or not?
• Store motor oil inside or in garage?

How often you open your hood? https://bobistheoilguy.com/forums/threads/last-time-how-often-do-you-open-your-hood.341128/

 

[Kira]

'Twas said above, "The oil feed holes burp". Not really...
Ever notice the chorus of flatulence noises after an oil change?

 

[BHopkins]

How often you open your hood? https://bobistheoilguy.com/forums/threads/last-time-how-often-do-you-open-your-hood.341128/

Wow! I missed that discussion. And such an important topic too! At least as important as pre-filling oil filters. Probably more important.

 

[PaxilPlease]

There is no significant difference (read zero) for the 1 or 2 seconds where there is no oil flowing after an oil change which usually happens about twice a year.