Full flow filters almost useless?

[Jim]

I have never been able to figure out just what a full flow filter is supposed to be removing from the oil. It can't be wear metals because they are too small. I left a filter in one of my diesel cars for almost 100,000 miles and when examining it with a microscope I found nothing in it.
I think a bypass filter removes the particles that cause wear and the full flow is just catching the small stones that fall into the oil fill hole when you change the oil. It would last the life of the car if nothing inside the filter decayed with age.

 

[Gary Allan]

I don't agree ..and 10 out of 10 manufacturers, when asked, prefer to change full flow filters, on engines so equipped, at regularly scheduled intervals.

I'd say that, maybe, with a bypass, the full flow filter may be a less useful appendage.

 

[Steve S]

I would say your theory is flawed to the extreme. Actually engine life greatly increased when the auto mfgs changed from bypass filtration to full flow filtration.

 

[Dyoel182]

Originally Posted By: Jim
I have never been able to figure out just what a full flow filter is supposed to be removing from the oil. It can't be wear metals because they are too small. I left a filter in one of my diesel cars for almost 100,000 miles and when examining it with a microscope I found nothing in it.
I think a bypass filter removes the particles that cause wear and the full flow is just catching the small stones that fall into the oil fill hole when you change the oil. It would last the life of the car if nothing inside the filter decayed with age.


If it wasnt filtering anything or doing any good, why would it weigh more after it comes off the car and has drained?

 

[mjo]

Originally Posted By: Dyoel182

If it wasnt filtering anything or doing any good, why would it weigh more after it comes off the car and has drained?

I dunno, maybe because the media and filter components are saturated with oil & water?

 

[Dyoel182]

Very funny.

 

[Spector]

Most filters and filter studies were done years ago when engines were not manufactured as well, when oils were no where near as good and when fuel injection was still not available or in its infancy.

You may see a difference in an engine that can go 300-400,000 miles in lieu of 200,000 by using a filter but for the average person ( vehicle use under 200,000 miles) IMO they are useless. Someone needs to do a few UOA with and without a filter and see if there is any difference in the OCI they normally run. I did (several 12,000 mile OCI runs) and changing the filter made no difference. They cannot trap the small stuff (under 15 microns) and the large stuff just is not produced anymore)! Like the 3000 mile OCI oil filters just keep on hanging on.

 

[Dyoel182]

There have been several used oil analysis done without filters that came back just fine.

 

[Jim]

The reason I started to wonder about this business of changing filters started when I couldn’t find a oil filter for my Moto Guzzi bike. I took the filter out at 2000 miles and looked at it. I found just a few very small slivers of metal in the filter. I picked them out and put the filter back in. Now at 45,000 miles the same filter is installed. I looked at it several times and I have never seen anything in it again.
I am not saying full flow filters are not doing anything and would never run an engine without one because it only takes a grain of sand one trip though and engine to do damage. I am saying that replacing filters so often is only lining the pockets of the people that say you need to change them so often.

 

[BarkerMan]

A major manufacturer does not but even a decal on a motor without a good reason. If you find a full flow filter on your engine it might have been put there on purpose. There has been plenty of time since the 50's when they started to appear on all passenger cars, to figure out if they are useful or not. Before that cars ran ND oil, lower cylinder pressures and larger cooling system and generally were not asked to work as hard. Engines were torn down more often and removing a cylinder head to "de-coke" an engine was a common practice. Many engines were flathead's and the process was pretty simple. Today engines are expected to last longer, run harder, get better fuel mileage and be virtually maintenance free.

 

[Jim]

Quote:
If you find a full flow filter on your engine it might have been put there on purpose.

Yes of course putting a full flow filter on an engine is important.
There is junk in a new engine. But after that is cleaned up there isn't much of anything to plug a filter and I have proven it by going almost 100,000 miles on one filter. This is on a dirty old Mercedes diesel. I have also gone 45,000 on one filter in my Moto Guzzi with an engine that works a lot harder than an auto engine. There is nothing in the filters when I check them.

Now if you really want to know something interesting, I have gone 17 years and 250,000 with my Cummins diesel with the original air filter. Just a quick cleaning with the vacuum is all it has ever gotten. Now before anyone says I am stupid, this engine runs like new and looks like will go 20 more years but the body is already falling off the truck.
I would rather take my wife to a fancy restaurant than pay for a filter that I don’t need.

 

[BarkerMan]

Jim, your maintenance plan is not shared my many others.

 

[Gary Allan]

I'll say.

 

[jmac]

Originally Posted By: Spector
Most filters and filter studies were done years ago when engines were not manufactured as well, when oils were no where near as good and when fuel injection was still not available or in its infancy.

You may see a difference in an engine that can go 300-400,000 miles in lieu of 200,000 by using a filter but for the average person ( vehicle use under 200,000 miles) IMO they are useless. Someone needs to do a few UOA with and without a filter and see if there is any difference in the OCI they normally run. I did (several 12,000 mile OCI runs) and changing the filter made no difference. They cannot trap the small stuff (under 15 microns) and the large stuff just is not produced anymore)! Like the 3000 mile OCI oil filters just keep on hanging on.



The original Bob of BITOG did something pretty close to this a while ago. might be able to still find it in the archives.

Now the Ea Amsoil filters with the new media have some particle counts of the oil with and w/o that do seem to make a difference.
Again search function...

 

[bob_ninja]

Would the same apply to smaller air cooled engine, such as in lawn mowers and snow blowers?
For instance, my lawn mower instructions are to change oil filter every other OCI. Same for Hondas. They seem to be confirming this theory to some extent.