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#1
Old 09-02-2004, 07:22 PM
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Change oil filter only?

Today I read an ad for a car for sale and the seller mentioned that he had a new filter for it, but hadn't yet gotten around to changing it. I've occasionally heard people mention changing their filter, but not the oil.
Old timers I know, most anyway, would never have done this. We might've changed the oil and skipped the filter, but not the other way around.
My question is, first, do people actually do that? And second, Have they always done so, and I've been living in a bubble all these 59 or so years?
Not seeking opinions as to the wisdom of such a deplorable act, I just wanna know if you or yours do it.
Peace,
mangeorge
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#2
Old 09-02-2004, 07:27 PM
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Quote:
Originally Posted by mangeorge
My question is, first, do people actually do that?
Yes. When I sold auto parts full time, I used to run into people that did this.
Quote:
And second, Have they always done so, and I've been living in a bubble all these 59 or so years?
I've heard of people doing it for as long as I can remember. I don't know what their reasoning is, other than just saving money.
#3
Old 09-02-2004, 07:35 PM
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I've heared of people just changing the oil filter too, but I can't understand it. It seems to me that the new filter will get "dirty" in no time.
#4
Old 09-02-2004, 07:50 PM
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I think you can find some people that does it... but I wouldn't think it's too common in a vehicle.

In my vehicles, oil/filters both are changed at the same time according to manufacture's recommendation.

For many years I was responsible for large industrial engines and turbines. The equipment would be in operation 24/7 for several years before routine maintenance. The oil was never changed. Some may be drained and fresh added if the oil began to show acid. The filters were changed according to pressure drop across the filter.
#5
Old 09-02-2004, 08:10 PM
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I have seen people do this. What they don't understand is that filters do not filter out everything, and oil breaks down over time.

It has been show, though, that synthetic oil takes much longer to break down than dyno oil, so it does not need to be changed as much. This might be a reason some people would only change the filter.
#6
Old 09-02-2004, 09:59 PM
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Amsoil reps used to claim that their synthetic oil was so good you never needed to change it, just change the filter and add some when needed. Testing by the SAE, IIRC, showed that Amsoil synthetic was actually the poorest synthetic oil at the time, and that all synthetics should be changed at a bare minimum every 12,000 miles due to a breakdown of lubrication and buildup of acids in the oil, along with a steady accumulation of micro-fine abrasive particles. IMO it's false economy to avoid changing the oil at the same time as the filter and risk additional engine wear - we're talking about only $5-$25, so why not?
#7
Old 09-02-2004, 10:25 PM
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You must change the filter on a regular basis for obvious reasons. You must also change the oil on a regular basis. This is because the oil is contaminated with not only particulates (which the filter gets rid of) but nasty byproducts from the combustion. This includes undesirable hydrocarbons such as gasoline. (Its particularly bad at startup, when the chamber walls are cold and the gas and other crap condenses on the chamber walls and runs down into the oil pan.) The oil filter will not get rid of gas and other hydrocarbons.
#8
Old 09-02-2004, 11:18 PM
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Some folks who dig extended drain intervals using high-end synthetic oils often plan on running the oil, say, 15,000 miles and changing the filter halfway through that. (And then again, obviously, when they change the oil.) Amsoil was the first thing that popped into my head when I read the OP, and I see that Una has already mentioned it. Whether or not it makes any sense to run an oil that long is probably a debate for another thread.

I've never heard of anybody advocating never changing the oil at all, though - except for the occasional nutjob who is convinced that it's a Big Oil scam. Those types tend not to be too big on ever changing filters either, though.
#9
Old 09-03-2004, 05:08 AM
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What Was The Deal With AMSOIL?

At every country fair I've ever been to there was always a table with some poor schmuck trying to sell this crap! As far as I can tell, ALL motor oils that carry SAE certification are the same..and if you change your oil/filter following the mfgs. directions, you will have no problems. How a little outfit like AMSOIL could produce a better product than a giant like Shell or Mobil, just makes no sense! in fact, I believe that the smaller oil vendors just buy their stuff from the big guys, add a few inconsequential additives, then repackage and sell the stuff. I had a friend who would never buy CASTROL oil (thoughmost foreign car dealers used it). His reasoning was that Castrol (NJ) was one of the largest recyclers of used motor oils..he always believed that castrol oils were a mix of virgin oil and recycled oils.
#10
Old 09-03-2004, 07:44 AM
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Quote:
Originally Posted by mangeorge
Today I read an ad for a car for sale and the seller mentioned that he had a new filter for it, but hadn't yet gotten around to changing it.

And why does he mention the filter in an ad? Is a new oil filter really that much of a selling point for a car? What do they cost--about 10 bucks? Less?
#11
Old 09-03-2004, 08:11 AM
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It's my experience that when changing the filter, you lose a good portion of the oil. So whether you like it or not, changing the filter gives you at least a partial oil change, unless you run it dry.
#12
Old 09-03-2004, 08:28 AM
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Quote:
Originally Posted by olefin
For many years I was responsible for large industrial engines and turbines. The equipment would be in operation 24/7 for several years before routine maintenance. The oil was never changed. Some may be drained and fresh added if the oil began to show acid. The filters were changed according to pressure drop across the filter.
What do you mean by "large industrial engines"? Big reciprocating diesels? I'm keen to know the details.

I can understand why a turbine can go for a long time without an oil change, it's because the oil in the bearings is almost completely sealed off from the combustion process. But in a reciprocating engine, it isn't. The piston rings don't seal anywhere near as well as the shaft bearing seals on a turbine. Like Crafter_Man said above, the oil gets diluted by unburnt fuel (although diesel isn't as bad as gasoline), and by the combustion products like water and sulphuric acid.

Anything you can remember about this would be appreciated.
#13
Old 09-03-2004, 08:59 AM
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I recall the guide on my Dodge Daytona Shelby Z - which was a turbo - highly recommended oil changes at 3,000 miles and oil filter changes every other oil change. And I did this.

It was explained to me and I sorta agree) that:

1. the turbo beat the hell out of the oil ( Ok, I can appreciate this general knowledge)

2. a filter is good past 3k - 6k being just fine and dandy

3. even filling the oil filter with oil upon install created brief dips in oil pressure and flow when restarting after a filter change. Turbos being extra sensitive to this were best served by having this happen a minimal number of times. The emphasis was on 3k as a MAX oil life, but that was way ahead of filter time and no good reason to risk oil flow issues.


Anecdotal evidence: I drove a hard 175,000 miles and never had a lubrication related problem. The engine, turbo and all, were outliving everything else. The might have been the only original mechanical bits when I sold it.
#14
Old 09-03-2004, 10:37 AM
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I change the filter every 10K and the oil (high temp. synthetic -- I'd never do this with standard oil) every 50k. I've never had any lubrication-related problems, and I regularly drive cars beyoud 200k.
#15
Old 09-03-2004, 11:05 AM
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Ever have any failed gaskets, Alan E Sheets?

#16
Old 09-03-2004, 03:39 PM
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Quote:
Originally Posted by Desmostylus
What do you mean by "large industrial engines"? Big reciprocating diesels? I'm keen to know the details.

I can understand why a turbine can go for a long time without an oil change, it's because the oil in the bearings is almost completely sealed off from the combustion process. But in a reciprocating engine, it isn't. The piston rings don't seal anywhere near as well as the shaft bearing seals on a turbine. Like Crafter_Man said above, the oil gets diluted by unburnt fuel (although diesel isn't as bad as gasoline), and by the combustion products like water and sulphuric acid.

Anything you can remember about this would be appreciated.
2400 HP Cooper-Bessmer natural gas internal combustion reciprocating engines and 10,000 HP Westinghouse split shaft gas fired turbines. All oil was routinely checked with lab analysis monthly for metals and acid. If it showed acid some oil would be drained and fresh added. This was normally not a problem. Natural gas burns fairly clean. During overhaul the oil consoles would be pumped empty, the oil stored, the consoles cleaned and if the oil sample was OK, the oil would be returned to the oil console.
You are correct in your statement.
#17
Old 09-03-2004, 04:54 PM
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Never. Why?

Quote:
Originally Posted by Philster
Ever have any failed gaskets, Alan E Sheets?

#18
Old 09-04-2004, 09:31 AM
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olefin: Thanks for the info, much appreciated.
#19
Old 09-04-2004, 11:10 AM
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Quote:
Originally Posted by Desmostylus
olefin: Thanks for the info, much appreciated.
Your welcome.
#20
Old 09-04-2004, 01:13 PM
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It seems that a lot more people change only the filter than I thought. Huge engines aside, it seems a little foolhardy at best. Especially considering the low cost.
But my faith in humanity has been restored by the preponderance of common-sense replies here.
Danka
#21
Old 09-04-2004, 01:14 PM
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Quote:
Originally Posted by olefin
Your welcome.
you're.
#22
Old 09-04-2004, 04:36 PM
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Quote:
Originally Posted by mangeorge
you're.
#23
Old 09-04-2004, 06:39 PM
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Do oil fileters when clogged up enough 'break thru" bascially, if the filter gets clogged enought, allows a 'door' to open to allow unfiltered oil to circulate, whcih would be better then the reduced flow flitered oil to circulate?
#24
Old 09-04-2004, 06:48 PM
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I switched to synthetic oil (Mobil One), on the advice of my friend, a fellow veteran. He was a helicopter mechanic in the Army. Anyway, he informed me that synthetic oil doesn't break down, like regular oil does. All synthetic oil does is get dirty over time, and to remove the dirt from the oil all you have to do is change the filter.
#25
Old 09-04-2004, 07:08 PM
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Quote:
Originally Posted by kanicbird
Do oil fileters when clogged up enough 'break thru" bascially, if the filter gets clogged enought, allows a 'door' to open to allow unfiltered oil to circulate, whcih would be better then the reduced flow flitered oil to circulate?
Yes, there's a oil filter bypass valve. At least on older cars.
Believe me, that feature's saved a lot of engines.
#26
Old 09-04-2004, 07:14 PM
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From this site
Quote:
oil filter bypass valve:
A valve in or near the oil filter which routes the oil unfiltered directly to the lubricating points; it comes into operation when the oil filter is clogged so that pressure across the filter is higher than the pressure needed to overcome the oil filter bypass valve spring.
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#27
Old 09-04-2004, 08:34 PM
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Originally Posted by Philster
Ever have any failed gaskets, Alan E Sheets?


Quote:
Originally Posted by Alan E Sheets
Never. Why?

Old oil tends to deteriorate gaskets. It can get acidic or corrosive. Maybe the synthetic wasn't as prone.


Didn't the car guys (car talk?) decide to drive a car without oil changes, just topping off when needed, just to see how far it'd go?
#28
Old 09-04-2004, 08:53 PM
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Quote:
Originally Posted by mangeorge
you're.


Maybe olefin MEANT "your welcome" when he wrote it. As in "(Here is/this post serves as) your welcome"


Donno just thinking...
#29
Old 09-04-2004, 09:56 PM
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Quote:
Originally Posted by Una Persson
Amsoil reps used to claim that their synthetic oil was so good you never needed to change it, just change the filter and add some when needed. Testing by the SAE, IIRC, showed that Amsoil synthetic was actually the poorest synthetic oil at the time, and that all synthetics should be changed at a bare minimum every 12,000 miles due to a breakdown of lubrication and buildup of acids in the oil, along with a steady accumulation of micro-fine abrasive particles. IMO it's false economy to avoid changing the oil at the same time as the filter and risk additional engine wear - we're talking about only $5-$25, so why not?
Link to the SAE test results, please.

Amsoil doesn't claim that their oil never needs to be changed. I use it in my '98 Chevy 5.7 Z71 and at 92,000+ miles I haven't had a oil related failure.

Amsoil

Amsoil Filters
#30
Old 09-04-2004, 10:37 PM
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Quote:
Originally Posted by kjckjc
Maybe olefin MEANT "your welcome" when he wrote it. As in "(Here is/this post serves as) your welcome"


Donno just thinking...
Hey... That was supposed to be private.
#31
Old 12-07-2012, 01:00 PM
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Amsoil and Mobil 1

What I have found on my 2010 Honda Civic is I change the oil filter every 3000 miles and top up the new filter and the crankcase with fresh synthetic oil. I can drive for 12 months and the oil change life percentage never gets close to 15%...That is when a certified Honda dealership says to bring the car in for oil & filter change. So, I run Amsoil top shelf for one year and just change filters. Then once a year I start all new.
#32
Old 12-07-2012, 01:32 PM
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Quote:
Originally Posted by JETWAKE View Post
What I have found on my 2010 Honda Civic is I change the oil filter every 3000 miles and top up the new filter and the crankcase with fresh synthetic oil. I can drive for 12 months and the oil change life percentage never gets close to 15%...That is when a certified Honda dealership says to bring the car in for oil & filter change. So, I run Amsoil top shelf for one year and just change filters. Then once a year I start all new.
I'd bet that you're spending more on oil filters and topping off with synthetic + a full change once a year then you would if you just left it in and changed it according to the regular schedule which ends up being about once every 10,000 miles or so.

(and yes, I know this is an old thread)

Last edited by Joey P; 12-07-2012 at 01:33 PM.
#33
Old 12-07-2012, 01:35 PM
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Quote:
Originally Posted by JETWAKE View Post
I can drive for 12 months and the oil change life percentage never gets close to 15%...
You do realize that this percentage is a nearly meaningless counter that represents no real-world value of time, mileage, oil condition, etc.? In my '07 Odyssey it rockets downward so fast I'd have to change oil every other fillup.

Reset it at your leisure and use any established rule of thumb for oil changes. Especially with a quality engine, synthetic oil and (I assume) normal driving habits, 10-12k miles and once a year is plenty.
#34
Old 12-07-2012, 02:20 PM
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Oil changes on much heavy equipment is done based on oil analysis, primarily because of 2 reasons- down time is costly, and because in the quantities required for a change for some of these machines with sumps in the tens of gallons, the oil itself can be extremely expensive, even though a quart of it may actually be cheaper than garden-variety Pennzoil.

Long-haul truck engines, locomotives and all manner of heavy equipment works like this, and the military does this as well with tanks, trucks, humvees, etc...

You can do it with your own cars, but the cost savings just aren't really there if you have a 1-2 gallon sump, since the analysis itself costs upwards of $20.

A lot of gearhead hobbyist types do it for 2 reasons- one, to see how long they can go on a single oil change, and two, because oil analysis is sort of like the automotive equivalent of a person's bloodwork at a physical- over time, you can spot increasing wear and possible engine problems via the results of the analysis.

Blackstone labs is a good example of someone who can do this for the average joe.

The general findings of the gearhead hobbyists who get oil analysis are that the mfgr. recommendations are pretty conservative, and the 3000 mile oil change is ridiculously too frequent for all but the most severely used cars running super-cheap oil.
#35
Old 12-07-2012, 02:48 PM
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Originally Posted by NitroPress View Post
You do realize that this percentage is a nearly meaningless counter that represents no real-world value of time, mileage, oil condition, etc.?
Actually I think that Honda now has an oil life monitor that's slightly more complex. It does actually measure the mileage, type of driving, number of cold starts, etc. However, it still has no way of directly measuring the condition of the oil, so it will read the same regardless of the type of oil used.

Of course, every time someone joins a site and digs up a nearly decade-old post just to sing the praises of Amsoil is always a little suspicious, but I guess mentioning Mobil 1 too gives him the benefit of the doubt for now.
#36
Old 12-07-2012, 02:56 PM
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Not completely on topic, but related... the age old standard of changing your oil and filter at 3,000 miles is completely nonsense with today's oil quality and filter technology.

The other half of that standard.... "or every 3 months" is particularly ridiculous and has made those quickie lube places millions of dollars every year.

Some might really be surprised at how unbelievably inferior oil was in terms of purification, lack of additives and general quality dating back to say the 50s and 60s.

Under normal conditions for non commercial/industrial use a change ever 5,000-7,000 miles even for non synthetics is perfectly fine.
#37
Old 12-07-2012, 05:14 PM
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You can do this? It didn't occur to me you could change just the filter. i thought the oil would pour out the filter opening in the engine. I've always drained the oil, then changed the filter, then refilled. But thinking about it now, the oil filter is higher than the oil pan.

So an anyway, if I'm changing both, does the order matter?

ETA: I'm thinking it might be easier to change the filter first, and let it drain into the empty plastic collection pan, then replace it and drain the oil pan.

Last edited by ZenBeam; 12-07-2012 at 05:16 PM.
#38
Old 12-07-2012, 05:25 PM
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Quote:
Originally Posted by ZenBeam View Post
So an anyway, if I'm changing both, does the order matter?
No.
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