Prefilling Oil Filters - Necessary?

Messages
4,232
Location
Kansas
That sounds like careless work to me. Those same bits of foil would end in the crankcase anyway.

A moment of diligence is all that is needed to wipe the jug down of dust or any dirt particles. I use a small knife to cut the foil seal unless it’s Valvoline which has a pull tab ring.

Valvoline still in business 🤔?? Just kidding 🤣 I guess it could be poured through a paint strainer if contamination was that big of a deal. I still would worry more about foreign matter getting sucked in through a poor quality air filter.
 
Messages
323
Location
D-FW, Texas
That sounds like careless work to me. Those same bits of foil would end in the crankcase anyway.

Well, in the crank case they would get filtered out I suppose. I guess if you add to the pre filter side you’re ok.

Believe you me, I have no opinion here on the subject matter, just citing, without reference, previous discussions.
 
Messages
1,480
Location
USA
Caterpillar has recommended for many years now to NOT prefill filters. Their reasoning is they’ve seen engines and other components damaged by prefilling filters. New oil can have some level of contamination in it and by prefilling the filter you run the risk of those contaminates circulating through the bearings
They probably were worrying about technician carelessness rather than harmful particles in new oil. I remember reading about it, and then they said the contaminants were organic under a microscope. That would be harmless and from things like a cotton cloth used to wipe a funnel.
I guess when I oil class 7 bearings with new oil from a bottle I am ruining them, but somehow it never seems to happen.
 
Messages
243
Location
Iowa
I usually do pre-fill my filters. Unfortunately, I did not on the last OC I did on the 2005 Jeep. Boy did the valvetrain tell me when the kid started it after we were done with the service...

Just my $0.02
 
Messages
3,030
Location
Chicago Area
If I can install a pre-filled filter without making a mess upon install, I fill. On the Ranger with a horizontal-mount filter that already made a mess when I took the old one off, no.
 
Messages
3,133
Location
Western S.C.
They probably were worrying about technician carelessness rather than harmful particles in new oil. I remember reading about it, and then they said the contaminants were organic under a microscope. That would be harmless and from things like a cotton cloth used to wipe a funnel. ...
Yes, and even if there are particles hard enough to damage bearings, they'll likely be resting at the bottom of the oil bottle, thus not a threat unless you can pour the whole bottle into the filter.
 

Backwoods41695

Thread starter
Messages
55
Location
AL
Thanks for the replies, everyone. Seems there is a lot of differing opinions on this subject. I suppose I will continue my prefilling habits. My F-150 is a bit of a pain though when prefilling the filter (filter location on a 5.4L 3 valve F-150 is kind of ridiculous). My Grand Marquis doesn't look quite as bad, though. Thanks, again!
 
Messages
167
Location
Charlotte, NC
I always do it. Is it necessary? I have no idea. Does it help prevent bearing wear? I have no idea. It gives me a little bit of peace of mind and some warm fuzzies inside.
 
Messages
1,173
Ever since owning a Camaro 3800 V6 in the 90’s with a horizontal filter I haven’t prefilled any oil filter on any car.
 
Messages
615
Location
CA
Nope.

Mustang’s filter installs sideways in a stupid location - already makes a huge mess taking it off. Truck’s filter installs dome end up, so no chance there.
 

blupupher

Site Donor 2021
Messages
6,818
Location
Katy, Republic of Texas
Is it needed, probably not, but I do it anyway most of the time, mainly because I can.
For vertical (open end up) I fill full. For those at an angle, I will fill at least 1/2 way. If sideways (or vertical with opening down, never had one of those), I fill it so it soaks the media (usually an initial fill of 1/2 way then spin the filter around so the media soaks it up).
For cartridge filters, I have not, but maybe I will add a qt of oil to the filter container once the cartridge is installed to soak them?
 
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