Do oil filters 'really' plug up?

[pgtr]

Over the years I have thought about this and am increasingly of the opinion that this is more urban legend than anything else. I just started thinking about all those square inches provided in a good Wix/ChampLabs/Purolator (my favorites) or whatever filter and the amount of particulate matter that would render the media essentially blocked to force oil around the bypass.

Obviously I change my filter at every oil change - afterall it's cheap insurance, required by the manufacturer, has old oil in it, etc etc etc. I'm certainly NOT advocating skipping the change but by the same token I'm not convinced that if you A) an engine is shedding chunks of metal in sufficient quantity to block the paper and B) that I should lay awake at night worrying about going a tick over the drain interval as I may be sacriligiously circulating unfiltered oil or something.

I figure if enough junk is in there during a normal drain interval to actually plug a filter - you've probably got more serious root cause problems anyway.

What do others think?

 

[OneQuartLow]

It isn't that they plug up entirely, but that flow is impeded to the point the bypass valve opens too often. Filtration effectively stops while the bypass valve is allowing oil around the filter media. This bypassing will happen earlier and more often as the filter becomes increasingly blocked, based on engine rpm, temperature, viscosity, etc.

What's too often? That would be easier to answer if we all had differential pressure gauges and knew how often the filters were in bypass. I believe Jeeper here is installing such a gauge. I was about to install dual filters assuming it would stop all bypass. Now I'm seriously considering a gauge myself, or I'll wait for what he learns.

David

 

[Spector]

I personally believe filters rarely go into bypasss due to contamination. I have yet to see one even close to being full of contaminants. I do think that due to efforts to make them as cheap as possible the drain back valves fail etc., but actually fill up with dirt, I seriously doubt it.

 

[dickwells]

Even with the bypass valve open the filter continues to take out contaminants due to the pressure drop across the element. I can say this because in about 65 one of my buddies bought a 60 Polara with about 60K on it. When we changed the oil the original mopar filter was still in place and totally packed. It weighed at least 5-6lbs. Car had been owned by a druggists wife and since back then the drill was filter every other change they must have asked her each time and she told them no. The lifters never did sound right on that 383 but it kept plugging away.

 

[pgtr]

I agree Specter. As I said originally (that reply was apparently DELETED) I think the bypass function rarely functions in practice. In fact I suspect the only time it is likely to ever function is on a very cold morning startup and/or w/ a very heavy oil.

(not that I'm advocating this) but even changing a filter every other oil change - I can't imagine it would plug up to the point that the bypass would actually be forced open. I just think it's a good safety backup measure that might get the cold morning workout.

Good story from 1965! Definately sounds like it came from the pre oil change happy era of today. 5 lbs indeed! - heh heh wish you'd cut that dude open.

cya
-T

 

[RalphPWood]

Pqtr,
Insurance is a good word for full flow filters. They only remove large engine damaging abrasives. When you drain the oil in a good engine the oil will be loaded with small engine wearing abrasives. The full flow filters will may be have a few large particles. As a rule the full flow filters can remove about anything large enough to see. Modern lube oils keep the small engine wearing abrasives from agglomurating enough for the full flow filter to remove them. Depending on which expert you talk to most engine wear is caused by abrasives between most engine wear is caused by abrasives between 5 and 10 microns. Some say 5 and 20. There are at least a dozen submicronic bypass filters available. I change my full flow filter about every 2 years or 20,000 miles. It is always clean. Some full flow filters use rubber parts that may not hold up longer. I've seen a couple of anti drain back valves get brittle. Under one micron abrasives are non abrasive in lube oil. I have 3 different filters that can filter to 1/10th of one micron in use. The oldest one in use is a Motor Guard bypass filter over 30 years old. I retired my 40 year old Frantz oil cleaner. It has setimental value. It has saved me a fortune in oil drains and engine wear.

Ralph

 

[Spector]

Issue really is do they (filters) make the engine last long enough and to the point where either the rest of the auto is useless or we grow tired of it. My opinion is that with modern oils we can easily go far enough on OEM equip (spin on full flow filters (even crap ones) and change the oil every 3000 with dino or 7500-15,000 with synthetic and the engine will outlast the rest of the car and boredom will set in (or driver dies first) before the engine dies from wear due to metal or dirt contamination. For 99.9 percent of the drivers this will be true I believe. I will define outlast to be at least 200,000 miles or 15 years! So, why bother going through all the effort of bypass, looking for the best filter etc.? It doesn't make any diff over 200,000 miles or 15 years whichever comes first.

to my knowledge no one has proven anything to contradict this! All anecdotal evidence.

 

[jason07-1zzfe]

I have heard from several oil manufacturers that submicron filtration would begin to remove additives from the oil

The smallest I would want any filter on my car to go down to is 8micron maybe 5...