PlsTell me what you know about filling oil filters

[91344George]

I don't pre-FILL the filters on my cars but I do moisten the filter with three of four ounces of oil just enough to allow the media to pass the oil through a bit more quickly on first start after the install of a new filter.

 

[CTownIntegra]

Originally Posted By: Danh
I don't pre fill for three reasons: I doubt it really matters, it usually creates a mess and it results in unfiltered oil circulating through the engine for few seconds.


Does new unfiltered oil need to be filtered?

 

[Danh]

Originally Posted By: CTownIntegra
Originally Posted By: Danh
I don't pre fill for three reasons: I doubt it really matters, it usually creates a mess and it results in unfiltered oil circulating through the engine for few seconds.


Does new unfiltered oil need to be filtered?


Probably not, but if there were contaminants in the oil (manufacturing mistakes do happen) or maybe were introduced into the oil by someone (someone maybe using a leftover container of oil for this purpose, or who opened the container on a windy day in a dusty area), they would go straight to the bearings. Again, not a big issue but then again that's what we discuss here, isn't it?

 

[CTownIntegra]

Originally Posted By: Danh
Probably not, but if there were contaminants in the oil (manufacturing mistakes do happen) or maybe were introduced into the oil by someone (someone maybe using a leftover container of oil for this purpose, or who opened the container on a windy day in a dusty area), they would go straight to the bearings. Again, not a big issue but then again that's what we discuss here, isn't it?

Absolutely. To be honest I never prefilled my filters uuntil I saw a buddy doing it a year or so ago on his VW. Then the gears started turning in my head so I tried it next time. May be just me but I noticed less rattle when I first started up.

I was changing the oil for my grandfather (Who taught me many years ago) and he saw me pre-fill his oil filter and asked why I did it. I told him to prevent a dry start. He replied that it made sense to him but he has never done it his whole life and his vehicles still last well over 150,000 miles and after he has sold them.

 

[91344George]

Originally Posted By: Danh


Does new unfiltered oil need to be filtered?

Quote:

Probably not, but if there were contaminants in the oil (manufacturing mistakes do happen) or maybe were introduced into the oil by someone (someone maybe using a leftover container of oil for this purpose, or who opened the container on a windy day in a dusty area), they would go straight to the bearings. Again, not a big issue but then again that's what we discuss here, isn't it?


The chances that fresh oil has a serious enough contamination factor is highly unlikely but never impossible. Like I said above why not just prime the new filter media with a few ounces of new oil instead of filling it up? That way the amount of unfiltered oil is tiny.

 

[George7941]

Here is an entire BITOG discussion on this very topic
http://www.bobistheoilguy.com/forums/ubb...988#Post1291988

 

[InvalidUserID]

I usually put as much oil in the filter as I can without having it spill out. On the cars that I do oil changes on, four of the five have the filter mounted horizontally so I can only fill it about halfway to avoid spillage.

On my girlfriend's Mustang, it is mounted somewhat vertically so I can fill it up pretty well and not have it spill.

It doesn't take much effort and whether or not it makes a difference, I honestly can't say. Oh well.

 

[surfstar]

I prefill partly with filters that are either horizontal or angled downwards. I use some of the oil to lube the gasket and threads, checking for burrs. I also know that not prefilling will not make a difference at all in engine longevity. It can give some people a warm, fuzzy feeling and help them sleep better at night. I do it out of habit, likely learned from reading on BITOG years ago.

 

[exranger06]

I always pre-fill the filters as much as I can. I've never spilled a drop either (maybe I'm just talented?

) On vertical filters, I fill all the way to the top. On horizontal filters, I fill about halfway. My father never did it, but to me, it seems like a good thing to do, so I do it. I'm not concerned about unfiltered oil going through the engine. The oil is about as clean as it'll ever get when it's in the bottle. Plus, what happens when a filter goes into bypass mode on a cold morning? You have *gasp* unfiltered oil going through the engine then, too!

I've heard that some big trucks or heavy equipment (something with huge engines with really big filters) actually REQUIRE pre-filling the filters. They hold so much oil, the engine would seize (or at least have significant damage) by the time the filter was finally full and getting oil to the engine. I have no first-hand experience with that, it's just something I read somewhere, probably on this site.

 

[berniedd]

I prefill because if I didn't my Honda's oil warning light would be on for 7 seconds after I started the engine. With the filter prefilled, the light would be on only 2 seconds. Is this significant? I don't know, but I sure feel better with prefilling. Note that the filter mounts horizontally, so I always roll the filter around to get all the filter pleats wet. I only prefill half of the filter capacity to avoid spilling as I mount it on the engine. Also, I add oil (using a medical syringe) to the small holes and not the big middle hole because the small holes are on the pre-filter media side and can catch contamination particulates. The big hole is already post-filter.

 

[mechtech2]

New 'dirty' oil is not a problem at all. It's new.
Filling or partially refilling a filter lessens the time to get oil to the engine parts by a small amount when restarting.
It can never hurt, and may help a bit .

There is not much to write a graduate paper about.

 

[nleksan]

BMW Canister Filters (K&N, Mann, Mahle): After removing old filter and just prior to draining old oil, I put the new filter in the canister after drizzling a bit of new oil on the pleats, turn it upsidedown, and fill 50-70% full and halfway through the process I flip the filter over while keeping the canister upsidedown. Then, after pouring the new oil in, wiping out the oil filter area on the block, I pour the oil from the canister (that wasn't absorbed by the filter) into the filter hole on the block, and then screw it on and start it up. I have never gotten an oil light with this method, and the first start is in no way different from a regular start (as far as I can see/hear, nor does it take longer). I do not know that there is any benefit to this, but it takes all of 3 extra minutes, I always take plenty of time on oil changes or other work on my cars (cathartic), and yes it gives me a peace of mind that while not based in fact is a good feeling nevertheless.
I do wonder, though, if my method of pouring oil prevents the occurrence of high-pressured air shooting through the system?(cartridge holds 2/3qt if full with filter in it, but I do not fill it all the way, instead to usually about 3/4 full sometimes half, and the filter soaks up about 1/3-1/2 of that, though I typically add 5.5qts thru fill hole, about 0.25qt soaked into filter, 0.3-0.4qts from canister into oil filter "well", and the remainder of the last bottle which is about 1/3-1/2qt is poured into filter "well" immediately before pouring from canister and installing filter)
It seems possible, or that it may minimize the risk, but I have no way to know...? Anyone?

Other Cars ("regular" twist-on filters; K&N, RP, M1, Bosch): prefill as much as possible first thing to let the media soak, and pour the excess into the oil filter well immediately before screwing in filter then starting the car. Same results as above.

 

[ryan_of_the_e34]

Thank you all very much for your responses. The information you all have provided, particularly about the true root of the Cummins situation, has been incredibly useful. If anyone else wants to chime in, please feel free to do so.

 

[SS1970chrysler]

Probably the only filters I don't/didn't pre-fill were the upside down mounted ones on old slant-6's.
Certain engines I had would knock awhile unless this was done.

 

[doitmyself]

Here is a link from the late Stinky Peterson (RIP) to his thread titled "Pictures of what's in new oil".

VERY UNFORTUNATE that the pictures no longer seem to be available, as I remember they were quite startling.

http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=111941&page=1

"Stinky" managed Butler CAT Oil Labs and in this thread he states "Yes I would definitely reconsider pre-filling filters,"

An excellent read to generate some debate here!

FYI, how can I remember this thread from many years ago, but don't remember what I did at work yesterday?

 

[garlicbreadman]

never in my integra. the filter mounts horizontally so any oil in there would spill out making a mess. if this was bad..honda would have designed a vertical mounting oil filter but they didnt which means its not bad for it and will not affect the life of the engine.

even for vertical mounting filters, never do...

 

[ryan_of_the_e34]

Well..
The assignment has been completed and submitted--with a desirable result for myself.

Thank you, all. I would not have been able to speak about this subject (with any competency) without your contributions.

 

[Donald]

So the question for the original OP is are you going to fill the filter the next time you change the oil?

One things to keep in mind is that there is a film of oil in the bearing surface and that does not drip away when the engine is turned off. Starting of the engine is at a pretty low speed compared to going 60 MPH and under no load.

Now starting an engine for the first time in its life its critical that everything be pre-lubed.

 

[SteveSRT8]

I can't even remember if it was 84 or 85 RX-7 I had had its oil filter mounted upside down on top of the engine. Seemed ok with the turbo like a cheap after run oiler.

That's the ONLY filter I never pre-filled. Even on my prehistoric Ford Vans we put whatever oil we could get into them prior to assembly. All my GM V-8's and my Mopar have the perfect upside down mount which means perfectly filled to the top every time.

Makes an oil freak feel good inside.

 

[Donald]

I will be doing the first oil change on my new to me 1999 Dodge Ram diesel, and the owners manual say to pre-fill the filter. Got my 3 gallons of Rotella T.