Are you supposed to pre-fill the NEW oil filter with fresh oil before you screw it on your truck?

If so, what is the reason?

What happens if you DON'T?

 

It's not necessary and nothing will happen if you don't.

 

If possible, yes, you should fill it. The oil pump in your engine pumps oil from the oil pan, through the filter, and then into the engine. If you have an empty new filter, there are a few extra seconds right after your oil change that the engine is running "dry", with no oil pressure. This probably won't kill the engine, but you can usually hear the engine making more noise before the oil gets to it, and I am sure there is *some* wear resulting. Still, there is gonna be a film of the old oil on the parts, and so long as you don't gun it until the oil pressure light goes off, the engine should be OK.

If the filter hangs off the bottom of the engine as on my van, it's easy to fill and there is no spillage, so I fill it. If it is sideways as in some Triton applications, you may end up spilling a couple drops of oil if you fill it a lot.

I've had some vehicles where the open end of the filter aims down...those you don't want to pre fill....

George

 

I always change oil on a warmed up engine, prefill my filters as much as possible, then disable the fuel pump, so the engine won't start.

Then crank it over with the starter, to finish filling the filter if it's mounted such that I cant completely prefill it & to burp the system of any air, build some oil pressure & put that new oil with it's fresh barrier lube where it's needed, before starting the engine after an oil change.

Another reason for changing the oil on a warm engine is that on the restart, a warmed up engine won't rev as high, nor for as long as a cold engine & it has things already wet down with lube before the oil change.
Warm lube drains quicker, so we get more of the old lube & contaminants out.

If we don't prefill the filter, or preoil the engine with the starter motor & start a cold engine, it revs high for a good while & before that big air bubble from a empty filter gets burped out we're depending on that old oils worn out addpacks barrier lube to MAYBE have lasted out the OCI & hung around on that cold engines parts long enough to offer up a little protection, until the new lube arrives!!!!

Seeing as how the main bearings are first in line for the empty oil filters big air bubble, they have to depend on the old lubes oil film, or barrier lube, to protect them until help gets there.

Same for over head cam engines & we need oil up there ASAP after an oil change too, so the ohc cam doesn't take beating while the system burps.

Flat tappet engines with heavily loaded valves can really put the hurt on a cam on a cold high rev restart, with no oil, because of the empty oil filter air bubble.

All good reasons for changing the oil on a warmed up engine, prefilling the oil filter if possible & or disabling the fuel pump so it won't start & cranking the engine over to burp the system & build some oil pressure & to pelube things with the new oils add pack, before the restart.

A bunch more oil changing thoughts for pondering.

 

My FORD Dealer does not pre-fil the FL820S Filter on my 5.4 Triton 3v, which sits sideways! I seriously doubt my engine will be Blowing up soon because I don't Pre-fill ...........

 

Of course it won't be blowing up soon...but prefilling is one thing you can do to make a little bit of a difference if you *really* care. Sort of like spending hours on the bobistheoilguy page to research fine details on different synthetic oil brands. I would bet that prefilling filters makes more of a difference in engine life than using some boutique oil brand like Royal Purple or Amsoil or something. And it costs nothing.

Your Ford dealer has nothing to lose and everything to gain if your engine wears out or blows up, especially if your warranty is up. And the quicker they can finish an oil change, the more money they make.

 

Well said!!!!!

 

All the reason more, not to use uneccesaary high viscosity oil, 10w40, 15w40, 20w50, mono weights in tight, emission controlled engines.

You want oil that immediately pumps when cold. Not thick, lazy, heavy oil, that gets even thicker laying next to cold metal parts, cold oil pan metal ect.

Still don't understand that philosphy, but many still love that thick oil on this forum...

FWIW, I don't prefill my oil filters, but I would if I had an oil filter that hung straight down (GM V8s ect.)

 

I say, if you CAN prefill, then DO IT. There's only benefits to doing it.

 

Of course, it's a big *IF*.

On my 351W, the filter is about 10 - 15 degrees off horizontal, plus it can only be reached from above, so I always spill about a pint oil when removing the spent filter, so the thought of pre-filling never even occurred to me. Don't want to spill any more oil.

 

Right, I can only put a little bit in my filter for my 302, it sits almost sideways. I can probably fill it 1/3. But, to me, that's better than nothing. It's at least getting the filter 'wet'. But, I don't want to waste any oil, either. I can hardly afford a 5-quart jug and Motorcraft FL1A filter from wally world.

But, yes, it is a big IF. But, I change oil on all my family's vehicles, and nearly all of them have an upright oil filter design, so I can fill them to the top.

 

I do on my truck(prefill) its easy to do.
If it doesn't help at least it doesn't hurt either right!!!!

 

It is a feel good thing for most people. The engine isn't going to be completely dry unless it sits for years. There is still plenty of oil in the oil lines and on the valves to lube the engine until the oil begins pumping.

 

I've never heard of anybody prefilling the oil filter, but it does make sense. It would be hard to do on my truck though cause the filter screws on horizontally

 

It is easy to do. Mine is mounted horizontally also. I do it sometimes, but like I said it is a feel good thing. I don't think it hurts, but I also don't think it helps any.