Never Prefill oil filters!

[bbhero]

Originally Posted by Shannow
Originally Posted by bbhero
Originally Posted by PimTac
Originally Posted by CR94
182 now posts about a practice never shown to have any significant effect, either positive or negative!




Yep and twenty seconds after you start the engine all that oil is filtered anyway.

I fill my filters out of habit but I am starting to realize that today's oil pumps work a lot faster and coupled with thinner oils and smaller filters makes this a moot point. This is not your old Chrysler with 10w40 and a filter that holds a quart in itself.



Great points PimTac ^^^^^^^^


Except that the debris that you put on the CLEAN side of the filter is straight into your galleries and areas of minimum oil film thickness (tenths of microns) before they make it to the sump...versus just putting them in the sump to be filtered.

(Oh, that and the foil, or the silver fish in the bottling plant)



Is the silver fish big enough to fillet ??

Does it taste like say flounder or cod ??

Hey... I don't prefill any filter either... I thought about your thinking on this and it made good sense to me.

Though I think it's not like stuff from 40-50 years ago either.

 

[ZeeOSix]

Originally Posted by Dallas69
You guys need to worry about something important.

... like what?

 

[Bill_W]

No worries here... I am an old dog, but I love to learn new tricks.

 

[WhizkidTN]

Originally Posted by ZeeOSix
Originally Posted by 69Torino
I don't, however, pre-fill oil filters at home. All the cars in the driveway have horizontally mounted filters, it would be a horrible mess.


On a horizontal filter you can pre-fill it to the point where the oil will not spill out the center hole when it's being installed. The horizontal filters I've prefilled that's been about 1/2 full before it will spill out while installing the filter.


Pretty much what I do as well for the wife's car.

 

[Coastie05]

I always pre-fill both my vehicles filters and the filters at work when I do an oil change. Just my preference...

 

[DGXR]

Originally Posted by caprice_2nv
Originally Posted by DGXR
Originally Posted by FordBroncoVWJeta
What about the oil you put in? Isn't it unfiltered?

Exactly my thoughts. So it's OK to pour oil from the jug directly into the engine. But if you pour oil into the new filter, it's a real problem!
Good grief, where do these myths come from?


I'm not sure if you read enough of the posts to understand the reasoning behind this argument... basically all of the oil you pour into the oil filler (at least in my cars case) goes right to the pan and gets pumped into the filter before it gets to any bearings. I never understood this before, now I'm on the fence about pre filling or not.

Yes I've read enough, and I already had a good understanding of this concern, with regard to wet sump engines anyway. Yes the oil flows down into the pan, and when the engine fires, the pump must fill the oil filter before any oil circulates into the engine. As a result, when I don't prefill the oil filter, the engine runs 5-7 seconds before the oil light goes out. When I do prefill the oil filter, the oil light goes out immediately upon firing. That is reason enough for me to prefill. Whether it is actually preventing wear, I have no idea. I just know the oil pressure builds immediately and that is a good thing

The point I made above is this, and it directly addresses the OP's concerns: prefilling the oil filter is not a risk. The oil you're putting into the oil filter is just as clean as the oil you're dumping directly into the engine. I.e., it is not possible for one to be OK and the other not OK. So those who want to prefill their filter, please do so, without any concern.

 

[FordMan59]

Been pre filling oil filters for 35 years and no harm done.

Been changing oil/filters for about 45 years, never prefilled a filter and no harm done.

 

[JohnnyJohnson]

Because the oil you add will go right into the engine unfiltered!

Wow you really think 4 to 8 Oz of virgin oil in say 7000 miles is going to make a difference? Boy I love to see someone Document that and prove your point.

 

[DGXR]

Oh no, don't pour 1/2 quart of new oil into the filter because it will cause problems.
But it's OK to pour 5 quarts of new oil straight into the engine, that's perfectly fine.

 

[blupupher]

Oh no, don't pour 1/2 quart of new oil into the filter because it will cause problems.
But it's OK to pour 5 quarts of new oil straight into the engine, that's perfectly fine.

As I said on the very first page of this thread, if you pour oil into the filter, it is being poured into the "clean" side of the filter, when you pour it into the oil fill, it is going into the "dirty" side of the engine.

I also said if you are worried about your sealed bottle of motor oil being contaminated, you have other issues.

 

[oldhp]

I have 2 Mopar 3.6 engines with the cartridge oil filter. I pre-soak them before installing them. I know, I know.................the sickness started a long time ago.

 

[Artem]

I’d rather have less engine chatter and faster build up of oil pressure upon start up if / when possible. I don’t own anything with an upside down mounted filter, so I’m a happy mechanic. always prefill to the brim.

 

[Jetronic]

Where did we read those words of wisdom? The oil filter will be in bypass until the oil pressure builds. The oil filter bypass valve works on differential pressure.

??? spring pressure that differential pressure has to overcome to open bypass.

 

[tolian21]

The car can run for some time (30-60 sec?) without any oil, parts are covered in oil film, so this is an overkill and waste of time.

 

[ZeeOSix]

The oil filter will be in bypass until the oil pressure builds. The oil filter bypass valve works on differential pressure.

The delta-p across the filter bypass valve is a function of the oil viscosity and flow volume. The delta-p across the filter will be the same regardless if there is any oil pressure in the system down stream of the filter or not.

In other words, the bypass valve will not open when the oil first hits a dry oil filter unless the oil viscosity and flow volume is high enough to cause delta-p high enough, just like if the filter was completely full of oil and the engine had full oil pressure.

 

[SammyChevelleTypeS3]

Hmm..

I have been installing oil via the 'Oil Fill Hole'

I open the cap then pour the oil into the hole..

LOL. I pour my oil into that hole under the "710" cap.

 

[PimTac]

The car can run for some time (30-60 sec?) without any oil, parts are covered in oil film, so this is an overkill and waste of time.

Which car does this?

 

[ZeeOSix]

Which car does this?

I saw someone do this once. Engine started making funny knocking noises after running ~30 seconds without oil.

 

[tolian21]

Which car does this?

Oil film stays in engine after oil is changed, so if it runs with no oil for few seconds, nothing bad will happen

 

[tolian21]

I saw someone do this once. Engine started making funny knocking noises after running ~30 seconds without oil.

I dont know exactly how many seconds, but few seconds with no oil will do no harm for sure.