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

[BHopkins]

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.

At no load.

 

[billt460]

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.

"Another person's fill hole"..... That really sounds nasty!

 

[Eddie]

Please provide a list of Manufactures who you say, don't prefill oil filters and provide a link for each. I question your generalized comment. Edward Hayes

 

[Racecarfan2]

This is a clip from Caterpillar's operation and Maintenance manuals. in this case a 966M but they all say the same thing.

 

[brages]

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.

I think it takes longer for the oil light to go out now that I quit pre-filling. I'm not sure, and I don't really care though.

 

[brages]

And here is another thing. When I had a Volkswagen Diesel, they were extremely profound in the manual, at pointing out how important it was to prefill the fuel filter with diesel fuel as full as possible, before installing it. The reason was so minimal air would be introduced into the fuel injection system. This would make the engine extremely difficult to start. And could run down the battery, and overheat the starter trying to evacuate all of the air out of the fuel system.

The same, "introducing contamination" deal applies. Even more so, because it would take very little to clog a diesel fuel injector in the first place. Which was the reason for the unusually large fuel filter to begin with. (Which was mounted perfectly vertical under the hood to facilitate prefilling).

I had an old diesel VW, and it didn't deal well with getting air in the system.

 

[rekit]

Have not tried it yet on our new to us Suburu 2020 Crosstrek, but I read you floor the go peddle and then crank it which is called a "Flood Mode". Supposed to cut fuel inj off. What a great feature for an engine with a oil filter mounted upside down on top of the engine! That solves the pre fill argument for me. I wonder if the Subie techs do this? LOL Probably never heard of it.....

 

[Bighorn2500]

I always pre-fill mine when changing the oil, however at the truck assembly plant I worked at they were not pre-filled ever.