I used to pre-fill mine till...

I had an issue with polaris 800 RZR twin motor...would not prime after oil change...lifters kept clattering...I unscrewed the oil filter til oil purged out by the seal, screwed it back in, clatter gone and system primed

I later called POLARIS tech line and the guy said this;

" when you drain the oil and change filer you create an air pocket between the pump and filter, If you fill the filter with oil it makes the pump cavitate as its using that air pocket to try and push fluid(oil) through the paper filter...Next oil change smear oil on filter o-ring only for install and start it up, should prime right away as its now pushing air through the filter and makes prime much easier"

So I have been doing that on every RZR since and no priming issues...

I also had a Kawasaki ZX6 do this as well...called kawasaki and they said nearly the identical thing as polaris.

Not every motor has this issue, our LS motors have a much better pump then POLARIS uses, but I would think the same concept might apply with the air pocket after draining oil from our motors..Since then I have installed it dry and oil pressure jumps up just fine after starting it...

After these experiences I do not see the need to fill the filter at all, and i'm starting to lean towards it slowing down re-prime.....Just my experience.

 

I've always prefilled the filter also, usually 3/4 so it doesn't spill out when I'm trying to screw it on.

 

I have always pre filled my oil filters.

I could see why Cat would say that though. Generally if you are filling equipment like that, you are pumping it out of a drum through a tube that rests on the engine while pumping. If a small piece of debris fell off of the pump tube and inside the filter it would not be filtered, it would go directly in the engine. If you were pouring it out of a clean qt I would think the chances of contamination are very rare.

 

Doesn't sound like a great idea to assume that whatever you are prefilling the filter with is particulate free, especially for fuel, on something that has injectors. Oil probably not as large a concern but I still wouldn't do it. If I was dead set on doing it I guess I'd prefill through the outer part of the filter instead of the inner.

 

This is interesting. I've never pre filled my oil filters...

 

Same.

 

Yea if plug the center of the filter, and fill it like that, it would still be filtered oil, how ever, that would take awhile.

 

When I started wrenching I was taught to do so. After you've serviced an engine there's components that are no longer lubed. In that brief moment when the engine starts and there's nothing in the filter so those components run dry. It may not be that big of a deal on gas engines compared to the larger diesel engines I've worked on.

 

Ya know, i gotta say the only times i have ever pre-filled were on diesels. my favorites were the 4wd 6.5TD where the filter layed on its side above the drive shaft. I cannot remember what the other truck was... I want to say a dodge cummins, that took a massive filter that would drink 2.5 quarts for pre-fill. other than that, i mean most new diesels ive done were canister filters. Okay so mainly Ford, and dodge. I cannot remember the newer chevy diesels as not too many came through where I worked because of the ungodly price for an oil change on a diesel. My truck always brought oil pressure up within 1 second or so from start after an oil change. my OBS was a little slower since it had a big filter

 

Ive only ever filled the filters on diesels and the very large (1/2 qt or more) gas engine filters. Ive always figured the LS filters are small enough that the time between start and full oil pressure is negligible.