Prefilling Oil Filters - Necessary?

Messages
1,452
Location
California
Prefilling an oil filter is not necessary because everything has a thin coating of residual oil which lubricates internal parts until oil pressure builds. And when the engine is restarted with an empty oil filter, it should be left at idle speed until the oil pressure / teapot light goes out (should be around 5 seconds depending on the vehicle and filter). The engine has very little pressure and stress at idle speed so nothing is getting excess wear while the filter primes.

Many of us prefill our oil filters just because it makes us feel so much better when the oil light turns off immediately.
 
Messages
103
Location
Northeast USA
I remember reading a thread some time ago where engine failures were attributed to foreign objects getting introduced during the filter pre-fill. IIRC, it was something like bits of foil from the bottle seal getting into the bearing journals. Someone said the filter the oil through a paint paper filter.
Wouldn't that be just as likely while filling the funnel as well? Seems like a far-fetched scenario.
 
Messages
3,133
Location
Western S.C.
... 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?
I don't pre-fill filters any more, because now I'm dealing with a horizontally oriented cartridge housing, which would be impossible to pre-fill without tilting the car over onto its right side.
 
Messages
197
Location
North Carolina, USA
Two of my cars have traditional spin on style filters so sure I do. However the Colorado has a cartridge style and on that one I do not. I've seen some videos where someone will use a small funnel to add oil to the filter housing in an attempt to "prime".
 
Messages
51
Location
Colorado
I have and have not and have never noticed a difference both in startup noise after a change or in oil related engine problems over all of these years. On my Subaru the filter is located horizontally so I tend not to mess with it even though I can do so without a mess. The amount of time it takes for oil to travel from the sump, filter and to the motor after a fresh filter install is inconsequential to me personally and the oil film left on parts is likely a bigger factor in protection...just like when you leave your car to sit overnight etc. Oil pumps move oil through a motor so quickly I have a hard time seeing how it would have any real world benefit for the tiny bit of oil pre-filled.

Now I have heard that at least wetting the filter element with oil before install can help with tears etc under pressure when a new filter is dry and that makes a little bit of sense but really have no real world data or evidence to back that claim up either. Anyway, doesn't hurt to pre-fill and don't think it hurts not to pre-fill either. It's just one of those things that we here on BITOG think about but just about no one else anywhere does lol!
 
Messages
355
Location
connecticut
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
I do all the maintenance on the machines at work which are all Cat and i don't prefill any of the filters. Never had a problem yet in 13 years doing this way.
 
Messages
35,258
Location
NY
If the filter is situated in a position where it can be prefilled I prefill it. I pour some in and let is soak in, then fill it to a point where I can safely install it w/o any oil spilling out. This is how I was taught and it is a habit that stuck with me.
 
Messages
49
Automotive application, nope. Oil filter void volume typically less than one pint. (The other half of the extra quart for filter change is in engine passageways.) Oil pump output at least 4 gpm. Time to fill filter ~2 sec.
 

JT20

$50 Site Donor 2021
Messages
3,640
I don't pre-fill mine and I just switched from a certain one to anotehr certain one and my car runs smoother already...
 
Messages
7,106
Location
FL, USA
For years I pre-filled my spin on filters, the past couple of oil changes I haven't bothered and I can stay I notice any difference. No noises either way, and the oil pressure warning light stays on for just as long.
 
Messages
1,519
Location
UT
I've done a lot of oil changes in my 47 years of driving. I have always done my own oil changes. And I have never prefilled an oil filter. Never even heard of such an idea until joining here on BITOG. Prefilling a filter would be a very messy, sometimes all but impossible task on by far the majority of engines that I have maintained. Very few of them have been vertical, mount surface up.

I've never experienced engine failure. I've never had an engine wear out. And I've put over 200k miles on a few different cars.

So no. I'm not a filter prefill guy. And I sleep very well at night after doing an oil change. I never even think about prefilling oil filters, except when the subject is brought up two or three times a year here on BITOG.
 
Messages
1,480
Location
USA
The pedal to the floor method to turn over the engine without starting is something i will try. I have a neighbor who struggles to start her car all the time because she insists on flooring the accelerator pedal. Leave it alone and the engine starts perfectly. Good way to pressurize the engine oil without the loads on the bearings.
 
Messages
31
As long as the vertical screws UP if it screws down as in MB for example, that wouldn't work ;) I never prefill, nor have I seen tech do it these days. It used to be recommended in the past (more years than I care to remember)
LOL , used to be you replaced the filter every 2nd oil change years back.
 
Top