Oil Change 'trick' or urban legend for less mess?

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Something I've been curious about and maybe some folks here can shed some light on this?

In cars w/ their oil filters inverted with the opening facing downwards (usually mounted on the top of the engine) - it's been widely held for years that if you poke a hole in the top of the oil filter before removing it, that the oil inside will drain out and it's less messy this way.

I've owned cars w/ this arrangement and at first followed this trick scrupulously. At first I thought this was a great trick but later I stopped doing it and can't say as it really made much difference one way or the other (what made a difference was wrapping a rag around the base mount to catch any excess).

If the theory is correct and the hole releases oil held in the filter then the theory must be that the oil is held in by a vacuum?

SO is this urban legend or a valid trick to less messy oil filter changes?

thanks,
 
I'd be concerned about introducing foreign material into the oil when I "poked" the hole...such as metal particles or paint from the outside of the filter.

Maybe a slim chance, but not worth saving a few dribbles.

Just my $0.02...


Tim
 
I used to do that but it takes time to drain, so now I use a nail in the old filter to open the rubber check valve and let the filter drain into the drain oil can. By the time I'm done putting in new oil and filter, the old filter is drained.
 
I just grab it with a Zip-Lock if spillage is an issue. Also, spraying nice clean concrete with water will repel any spilled oil.
 
Whoops - I'm talking about when the filter is ON the car. Some cliam putting a hole in the top allows it to drain just before removing it from the mount point on the engine.

The more I think about it, the less I buy it. I find it hard to believe that an inverted mount oil filter actually holds oil by vacuum - thoughts?

---

That nail trick is a good one for those anti-drainback valves! Another nail in the coffin of the 'vacuum theory'?

thanks,
 
Well....
I used to do just that on a Mazda RX7. My details are kind of hazy because that was in 1979 - 80. But the filter was at the top left rear of the engine and pointed straight down.

I am pretty sure that if I just took it off with no prep, it spilled all over and was a mess.
After I started punching a hole in the top with a hammer and nail, no mess.
 
Yes, this method works great. I use it on my Ford explorer all the time; no more dirty oil running down the arm. As for contamination getting in from poking a hole; unless it can defy the force of gravity, and swim up into your oil galleries, you should have no problems.
 
quote:

Originally posted by dkcase:
Well....
I used to do just that on a Mazda RX7. My details are kind of hazy because that was in 1979 - 80. But the filter was at the top left rear of the engine and pointed straight down.

I am pretty sure that if I just took it off with no prep, it spilled all over and was a mess.
After I started punching a hole in the top with a hammer and nail, no mess.


Thanks dkkase - yes, that's an example of one. '79 ? Well we'll make due w/ your memory!
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This is more theoretical anyway.

So are you saying that the oil is held in place by vacuum?

The opening at the top of the oil bottle is probably smaller than an oil filters but comparable in size. When it's inverted to fill up the crank - you don't need to poke a hole to drain it out do you? Why or why not?
confused.gif


thanks,
 
Bingo!

Thanks for the verification widman - this is an urban legend that has gained a lot of credence in many circles for some unknown reason. I've tried it both ways even though I knew there was no vacuum just for kicks - no difference either way.

thanks,
 
there is no vacuum. the anti-drainback valve is there on most filters. (some, such as vertical mount Cummins) yave a solid tube inside that require the filtered oil to go to the top of the tube before flowing down into the engine.
punching a hole in the outside of any filter will let it drain to the outside, not to the engine, so you will dirty the engine just the same unless you put a hose on your hole.
 
The anti-drainback gasket only prevents the return of DIRTY oil back through the inlet ports to the sump. It has NO effect on normal seepage THROUGH the filter medium, which will clean the trapped oil before it flows out the threaded exit port - especially with inverted mounts. (presuming the filter is not hopelessy clogged - another reason to change the filter at EVERY oil change...) You do not need to punch a hole in the can. Gravity alone will drain an intact inverted filter if you give it 15 - 20 minutes after engine shut-down before you loosen the filter from its mount. You'll find there's little if any spillage. Punching a hole only speeds up a process that will occur anyway. As others have pointed out, there is some risk, however slight, of introducing contaminants into the engine oil galleries if the can is punched through, though.

[ September 27, 2003, 03:14 PM: Message edited by: Ray H ]
 
quote:

Originally posted by Ray H:
The anti-drainback gasket only prevents the return of DIRTY oil back through the inlet ports to the sump. It has NO effect on normal seepage THROUGH the filter medium, which will clean the trapped oil before it flows out the threaded exit port - especially with inverted mounts. (presuming the filter is not hopelessy clogged - another reason to change the filter at EVERY oil change...) You do not need to punch a hole in the can. Gravity alone will drain an intact inverted filter if you give it 15 - 20 minutes after engine shut-down before you loosen the filter from its mount. You'll find there's little if any spillage. Punching a hole only speeds up a process that will occur anyway. As others have pointed out, there is some risk, however slight, of introducing contaminants into the engine oil galleries if the can is punched through, though.

I agree Ray but what about this: Aren't some anti-drainback systems designed to help keep a 'full' or partially filter so the engine has oil flowing immediately at startup. Seems there was a bruhaha a while back about some cars w/ either inverted or side-mounted filters that didn't have anti-drainback (depending on filter brand) and the owners often complained about brief 'clatter' in the lifters at startup.

'IF' that is the case - then merely the drainback valve by itself in the case an inverted oil filter, may not be 'just' to prevent drainback but also to hold oil for immediatley flow at startup...? (if the center tube is solid and not perforated for flow... see 'widman' post above)

Thoughts?
 
quote:

Originally posted by pgtr:
I agree Ray but what about this: Aren't some anti-drainback systems designed to help keep a 'full' or partially filter so the engine has oil flowing immediately at startup. Seems there was a bruhaha a while back about some cars w/ either inverted or side-mounted filters that didn't have anti-drainback (depending on filter brand) and the owners often complained about brief 'clatter' in the lifters at startup.

'IF' that is the case - then merely the drainback valve by itself in the case an inverted oil filter, may not be 'just' to prevent drainback but also to hold oil for immediatley flow at startup...? (if the center tube is solid and not perforated for flow... see 'widman' post above)

Thoughts?


If there's an internal antidrainback device in the engine, then I would agree with your point. And, many cars do not have an inverted filter design. How much oil is retained in the filter more than 20 minutes depends on the angle of distribution with a vertical, but non-inverted filter mounting literally not draining back at all on level ground. To use my own car as an example, it has an aluminum V-6 with a cast aluminum "oil sump extension" bolted to the bottom of the block. The pressed steel pan is then bolted to its bottom. The oil filter is mounted horizontally to the cast aluminum sump extension. the first time I changed oil, I got a gusher in the snoot because I didn't wait after shutting off the engine - the spin-on filter was still essentially full. Fast forward 2,600 miles. This time I waited about 15 minutes and when I loosened the filter this time, there was only a small dribble easily caught with a couple of paper towels. (The filters for my car DO have an antidrainback flap visible right through the inlet holes.) But to put an antidrainback flap in an oil filter's discharge port would defy logic. Oil flow could not occur at all in that scenario. You can block return of dirty oil with the anti-drainback valve at the inlet ports, but you can not block seepage of oil through the filter medium at all - it has to be porous to oil flow by common sense. Once into the perforated center tube, oil, a liquid obviously, is gonna do what any liquid does - follow the path of least resistance until or unless something else stops it. One other point. There will ALWAYS be SOME residual oil SOMEWHERE in the engine. It doesn't all drain back into the sump. (There've also been discussions at length on this forum about how to maximize oil drain at change time.) The folks with clatter at startup may be using super-efficient low micron pass filters or clogged filters that rely on the bypass valve to supply oil at cold startup - and THAT won't happen until the full-flow filter is pressurized to the release point of the bypass valve - which would imply that drainage from the filter DID occur while the vehicle sat idle. That clatter could be the result of oil stavation during pressure-up. Or it may be indicative of one or more marginal hydraulic lifters. There's the question of whether some of these people are using too viscous an oil grade for their prevailing climate, too. Or any combination of the above. I'm not saying you're wrong, pgtr, just that there are various avenues to research before an answer to the valve clatter issue can be resolved. I know of no automobile oil filters with a solid center tube. (Anyone have any examples they'd care to share in this thread?) Widman's reference to Cummins filter design was a new one for me, but it sounds like a special case that's applicable to specific (and probably heavy duty at that) engines. Whether the Cummins design is intended to hold oil for startup or merely a diffferent way to tackle backflow of contaminated oil into the sump is beyond me. But, I'll give credit to Cummins for knowing what they're doing - Cummins has a well-deserved reputaion for doing a LOT of things right in heavy-duty engine design and doing them for a LONG time. But, I question whether all that company's design considerations are in common usage, or even applicable, across the board for the more mundane and lighter duty engines that we're familiar with in daily use. But, live and learn...

[ September 28, 2003, 02:23 AM: Message edited by: Ray H ]
 
quote:

But to put an antidrainback flap in an oil filter's discharge port would defy logic

Indeed it does at that. But I'm confused, who said anything about doing that? Besides you'd have to drop the term 'back' in such an application
smile.gif


==================

All I'm saying is that in engines fitted w/ an inverted filter - it would be interesting to verify if the OE filter in conjuction w/ an anti-drainback valve installed on the filter itself has an inner return tube that is either A) perforated w/ holes or if it is solid (to the top) in comparison to aftermarket filters. E.g. the oil flows thru the filter and then thru the holes in the tube or flows thru the filter, hits the tube and then travels upwards and over the end of the tube and down... It would be an easy comparison point between OE and aftermarket filters if anyone is interested.

To be clear: the whole issue of keeping oil in the filter after shutdown for next startup is one that I have heard elsewhere in conjuction to oil filter design but not one I am personally knowledgeable of or advocate one way or the other. All I know is that some other folks w/ Japanese cars years ago argued this point w/ respect to OE vs aftermarket filters of 'that' time and Chevy SB guys like to prefill their filters at installation.

==================

On preventing 'dirty' oil from returning - generically speaking - what exactly causes the oil to become dirty when the oil pump picks it up in the pan and pumps it up to the filter that would cause manufacturers to not want it to return back to the rest of the oil in the pan?

==================

quote:

The folks with clatter at startup may be using super-efficient low micron pass filters or clogged filters that rely on the bypass valve to supply oil at cold startup ... I'm not saying you're wrong, pgtr, just that there are various avenues to research before an answer to the valve clatter issue can be resolved.

THe engine clatter thing is only something I mentioned from vague memory in connection to anti-drainback and merely a point of curiosity - I am not the one that is or was saying that. Years ago I remember many Honda and Toyota folks and perhaps others online claiming that the only 'good' filter was from the dealer - they claimed that these filters had proper anti-drainback valves installed and popular aftermarket filter brands of that time did not. THey further claimed that the lack of anti-drainback valves caused brief clatter at startup even in new engines and swore that the difference could be observed by a simple filter swap. In more recent years I have noticed the increased presence of anti-drainback valves in many filters. That includes filters in an inverted mount application that previously never had them (as far as I observed & can recall). I really don't know anything about this specifically just passing on the popular wisdom as I heard it at the time. THis discussion all predates the existence of this particular bulletin board AFAIK (thought it may have been discussed here as well). So as far as right and wrong - you'll have to take it up w/ other folks from another time
smile.gif
 
pgtr, my comment about putting an anti-drain flap to close off the exit port was a facetious attempt to make a point that doing so would be the ONLY way to hold oil in an inverted oil filter at engine shut off. If the center tube is perforated, oil WILL drain completely out of an inverted filter after the engine is shut down, or at least to the the lowest level of the exit port for horizontally or near-horizontally mounted spin-on filters. The ONLY oil filter mounting method that will allow the filter to remain full of oil after engine shut down is mounting it vertically, but not inverted.

Bror Jace, there have, indeed, been cars available in North America with inverted spin-on oil filters. At least Mid-60s, if not earlier, and later, at least through the early 70s of AMC I-6 engines and mid-70s through the end of availability in the U.S. of the brand of I-4 Peugeot diesels. I owned examples of each.

[ September 29, 2003, 09:14 PM: Message edited by: Ray H ]
 
“In more recent years I have noticed the increased presence of anti-drainback valves in many filters. That includes filters in an inverted mount application that previously never had them …”

pgtr, I believe you are correct. Them furrin’ cars came out with features which later became (largely) industry standards. The more complex oil filters are one, multi-valve engines are another. I’m pretty sure there are others as well even if none come to mind.

I can’t believe any manufacturer would put a filter mounted upside down on an engine. Thankfully these are pretty rare and I've never owned one. Before I’d allow a design like this, I would use a remote mount but I know these are more expensive and prone to leaking from the additional connections so mfrs would turn to wrong-side-up, fuster-cluck configuration as a last resort.
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However, I would never pierce the canister while it's still mounted and let the dirty oil (the dirtiest of all the oil in the system) drain back into the engine where at least some of it would remain. Some of the particles, once trapped in the media, might become free with the (albeit small) reverse flow of oil back down through the filter and into the motor. No thanks, I’ll just surround the filter with rags or paper towels and deal with the mess as best I can.
dunno.gif


As for what holds the oil inside the filter while it’s upside down, I’m not sure. HOWEVER, the oil is held in there and just inverting it for 15-20 minutes will not allow it to drain out completely. My past Hondas and new Nissan use a horizontally mounted filter and after removing it, most of the oil would stay in the filter. I’m pretty sure I’ve left these things overnight and they still felt heavy(full) the next morning. Currently, I pull the filter off, place it gasket-down in an empty pan and then put two holes through the end of the filter; one in the center and another a little off to the side. Then the oil comes gushing out.
wink.gif


Even like this, I often allow filters to drain overnight to get as much of the oil out of it as possible before it gets tossed in the trash. It rests on a couple sticks or other thin, long pieces of wood a few inches above the pan. All used oil is brought to a reclaimation center for (hopefully) recycling.

--- Bror Jace
 
Bror,

I keep hearing and reading that more and more (and this is probably pretty common w/ horizontal mounted filters) the reason for the ADBV isn't so much to do w/ keeping dirty oil from going back to the pan but to keep it in the filter to prevent 'dry' starts which may result in brief 'clatter' at startup. I guess foreign makes may have initiated mounting filters in places where

I think the hole poking thing is urban legend myself that a few extra minutes of letting the oil filter remain on the car won't resolve. I just don't see how the 'vacuum' theory 'holds water'
smile.gif
so to speak given the size of the return hole.

---

In your case I suspect most of that oil is being held in largely because of, among other things, the ADBV. Perhaps if you just put a nail up thru the ADBV enough to pry it open and let the filter sit - it would drain better?

I would 'think' that the oil would seap out past the media and thru the perforated center tube if you let it sit but now that you mention it, I've left filters sit for a day or better w/ perforated tubes and ADBV and they still seamed 'heavy' as in full too!
dunno.gif
Just a wild thought but I wonder if there is something about the media that resists 'seeping' or 'soaking' thru?

thanks,
 
quote:

Originally posted by Ray H:
.... snip If the center tube is perforated, oil WILL drain completely out of an inverted filter after the engine is shut down, or at least to the the lowest level of the exit port for horizontally or near-horizontally mounted spin-on filters. The ONLY oil filter mounting method that will allow the filter to remain full of oil after engine shut down is mounting it vertically, but not inverted. .... snip


Well maybe in a month. My experience is that filters I remove will not drain even over several days. If I want to separate the oil before recycling the filter and oil, I have to drill a hole in the filter. What brand of filters are you using? AC's, Purolators, and I think even Frams won't drain.
 
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