Dirty Oil Filter...Better than New One?

   / Dirty Oil Filter...Better than New One? #1  

Henro

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Few miles north of Pgh, PA
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Kubota B2910, BX2200, KX41-2V mini EX
My owner's manual says change engine oil at each 100 hours. I change it at 50. I used to change my oil filter every 50 hours as well. Now the engine oil filter price jumped to about twice the cost of the oil... /forums/images/graemlins/frown.gif

My manual says to change the engine oil filter every 200 hours. The filter prices is making me want to follow the manufactur's recommendation.

Aware that I was acting dangeriously (by thinking), I continued to think about what I had been/may be doing. And I now wonder if changing the engine oil filter every 50 hours is actually hurting, rather than helping my engine...???

I have heard that air filters actually filter a bit better after the get a little dirty, the dirt actually adding to the cabability of the filter to "grab" small particles.

Could the same thing happen with an oil filter? Could a slightly used filter actually be doing a better job than a new one just put in service? By changing at 50 hours, could I actually be removing a filter that was in its prime and putting on a new filter that needs to filter a while before it reaches peak performance?

Might I actually be doing less, rather than more, by changing my oil filter four times more often than recommended?
 
   / Dirty Oil Filter...Better than New One? #2  
Yes, a filter will become more efficient as it becomes loaded with particles, but there is a point when the filter becomes fully loaded and then begins releasing particles at about the same rate its capturing them.

I've tested several brands of oil filters all but Fram Tough Guard, Pure One, & a synthetic AC have fairly open pore structure, so leaving an oil filter on for the recommended interval wouldn't be a problem, especially if you have maintained the engine well you shouldn't have sludge falling out into the oil. After all the manufacture validated that maintenance interval.

Because most oil filters are so open, I think they do less than most believe they do, so changing them more often isn't doing any harm either.
 
   / Dirty Oil Filter...Better than New One? #3  
Wonder when they'll start using indicators. Something similar to what's on air filters. That or a monitoring system. Our nation could save a lot of oil. The oil/lube places would hate it though.
 
   / Dirty Oil Filter...Better than New One? #4  
So I guess the Fram and Pure filters work too well since they do not have the open pore "feature " ?
 
   / Dirty Oil Filter...Better than New One? #5  
Bill, your theory makes considerable sense to me. I know that the dustbag on my woodworking shop's dust collection system is supposed to develop a thin "mat" of dust before it achieves it's maximum filtering efficiency and that once that happens, the period inflation and deflation of the filter bag results in the thicker deposits being shaken loose and falling into the collection bag.

As usual, Bill, you have started a provocative topic and one in which it may eventually be established that "less is more." /forums/images/graemlins/grin.gif
 
   / Dirty Oil Filter...Better than New One? #6  
i can't help but wonder if some of these specs for changing oil and filters has a lot to do with the warrenty and the desire to make $$$ on oil and filters. i change the oil 2 x a year and the filter once a year (about 50 hrs max) i am ot one to skimp on maint. ut some of those specs are are tad out of line. just MHO
 
   / Dirty Oil Filter...Better than New One? #7  
Dirty oil filters work better???

Without a filter differential pressure one has no idea of what is going on.

A full flow filter could just stop all flow or have a bypass open and do no filtering.
A bypass filter could plug up and filter nothing without interferring with the oil flow.

Most spin on filters have a pressure activated bypass built in so again one does not know whats happening.

Egon
 
   / Dirty Oil Filter...Better than New One?
  • Thread Starter
#8  
Egon,

Sounds like it is time for a new question... /forums/images/graemlins/grin.gif

When does an oil filter get "dirty?"

My guess is it is probably dirty at 50 hours and almost filthy at the recommended 200 hour change point...

Thanks to all for their input. I am going to change my thinking and not feel bad for following manufacturer guidlines for filter changes...

I can't help but remember there was a time (or so they tell me) when the best medical minds on the planet used to drain blood from sick people to "let the bad out..."

Just keep thinking that excessive filter changes may be something along the same line...not sure what exessive is though. Maybe every 100 hours or once a year would be perfect...somewhere between dirty and filthy, and well before obstructed...that'll be my target... /forums/images/graemlins/smile.gif
 
   / Dirty Oil Filter...Better than New One? #9  
Henro,
Just use the Fram or Pure filters and change often. They start out filtering better than the rest and apparently that causes problems for some who leave them in there too long, get too dirty and cause low oil flow. Good filter just left in too long.

As to how fast oil gets dirty, it depends mostly on the condition of the engine. Blowby, over ritch fuel, etc will make oil dirty sooner.
 
   / Dirty Oil Filter...Better than New One? #10  
I wouldn't say they work too well, just better than the rest of the pack. I'm still not sure they would plug. Like one of the others said there is no way of knowing unless you put a pressure indicator in front of the filter.
 
 
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