How often are filters in bypass mode?

[ZZman]

We often worry about dirt holding /clogging or filtering efficiency. But how often does a normal vehicle filter actually go into bypass mode?

1. Has 0w oils reduced bypass in cold weather?
2. Does a high pressure oil pump automatically mean more bypass occurs?
3. Does bypass ever occur in warm to hot weather if filter isn't clogged?
4. Does running a heavier oil automatically increase bypass events?
5. How long does bypass usually last?

 

[dlundblad]

I am betting they go into bypass a lot more than we think.

Another question is how many inlet side contaminants are picked up and pushed through the bypass only to go back into the engine?

***
1. I think 0w oils still bypass in cold.
2. I don’t really understand high pressure oil pumps. Rock Auto states they are good to add to a worn engine.. I wonder if it’s higher flow and not a higher pressure. Either way, I can’t see the bypass frequency changing.
3. Yes
4. No. This is a similar concept to question 1.
5. I imagine once the engine and oil are up to temp, a bypass can happen with any sudden increase in RPM. A 0-60 acceleration I imagine is bypassing the entire time until the RPM’s decrease to a cruising speed. Any time you downshift on a hill or to pass someone too. Heck, the AC kicking on (increased load) likely causes it too.

 

[Jetronic]

Bearings will draw the oil they need and have available at the surface, but no more. so...

1) Not very likely. The oil pump is more likely to be in bypass though when it's very cold. When you use an oil below the temperature it's rated for, it's not likely to pump anyway, so bypass in the filter is the least of your worries. The bearings draw less oil when the oil is more viscous, so don't need as much supply.
2) No, you can't really increase the oil circulation through the engine, so pressure will rise when you try to, and oil pumps will hit bypass.

The only way to know, is to fit an oil pressure gauge after the oil pump, if max oil pressure drops by the oil filter bypass setting, you know the filter is in bypass. I maintained some volvo equipment that had this as the criteria for an oil filter change, not miles or time.

 

[Kira]

The OP's title question has occurred to me often.
Jetronic is likely the correctist; you gotta measure to know.

Me? I think there are filters where the element goes crooked and sticks in a "cock-eyed" manner or a flimsy spring readily collapses.

 

[KCJeep]

We often worry about dirt holding /clogging or filtering efficiency. But how often does a normal vehicle filter actually go into bypass mode?

1. Has 0w oils reduced bypass in cold weather?
2. Does a high pressure oil pump automatically mean more bypass occurs?
3. Does bypass ever occur in warm to hot weather if filter isn't clogged?
4. Does running a heavier oil automatically increase bypass events?
5. How long does bypass usually last?

Great questions!

I’m with @dlundblad I believe bypass events are more common than we tend to think.

 

[BMWTurboDzl]

We often worry about dirt holding /clogging or filtering efficiency. But how often does a normal vehicle filter actually go into bypass mode?

1. Has 0w oils reduced bypass in cold weather?
2. Does a high pressure oil pump automatically mean more bypass occurs?
3. Does bypass ever occur in warm to hot weather if filter isn't clogged?
4. Does running a heavier oil automatically increase bypass events?
5. How long does bypass usually last?

Bypass occurs due to a resistance of flow through the oil filter media.

I doubt it happens at all unless the filter is extremely dirty since automakers are incentivized to insure filtered oil continues to flow under all operating conditions.

I suppose if you can get any ide by learning the psi at which the bypass valve operates for your specific filter

 

[jetman]

my guess is
the filter = almost never
the pump = often in colder climates

 

[Jetronic]

my guess is
the filter = almost never
the pump = often in colder climates

the pump even a lot in hot climates, when revs rise

 

[Bellavita]

We often worry about dirt holding /clogging or filtering efficiency. But how often does a normal vehicle filter actually go into bypass mode?

1. Has 0w oils reduced bypass in cold weather?
2. Does a high pressure oil pump automatically mean more bypass occurs?
3. Does bypass ever occur in warm to hot weather if filter isn't clogged?
4. Does running a heavier oil automatically increase bypass events?
5. How long does bypass usually last?

Good Morning ZZman,
In the Fram YouTube video "Filtration and Engineering Testing - 2011 FRAM Challenge Video 2", Gary Bilski-Fram Filtration Engineer stated the valve can open 25,000 to 30,000 times in the life of a vehicle and that the Fram by-pass valves are engineered for 1,000,000 cycles.

 

[ZZman]

Bearings will draw the oil they need and have available at the surface, but no more. so...

1) Not very likely. The oil pump is more likely to be in bypass though when it's very cold. When you use an oil below the temperature it's rated for, it's not likely to pump anyway, so bypass in the filter is the least of your worries. The bearings draw less oil when the oil is more viscous, so don't need as much supply.
2) No, you can't really increase the oil circulation through the engine, so pressure will rise when you try to, and oil pumps will hit bypass.

The only way to know, is to fit an oil pressure gauge after the oil pump, if max oil pressure drops by the oil filter bypass setting, you know the filter is in bypass. I maintained some volvo equipment that had this as the criteria for an oil filter change, not miles or time.

I never realized the oil pumps bypass too. Is this built into all vehicle oil pumps?

 

[Sayjac]

Best information seen on this subforum (including but not limited to some oil pressure gauge testing (dp) done by respected member Jim Allen) says oil filter bypass events are rare and when they do occur of short duration.

That is what 'I' take as solid information.

Yes, engine oil pumps have a valve built in that is generally referred to as oil pump 'relief valve". That as opposed to oil filter bypass valve. If the oil pump relief valve not functioning properly, the engine could/would have real issues, including engine failure.

 

[Jetronic]

I never realized the oil pumps bypass too. Is this built into all vehicle oil pumps?

yes, or it is a seperate valve after the oil pump. It limits the maximum oil pressure. Bypass oil goes back to the sump or the intake side of the pump.

 

[Jetronic]

Best information seen on this subforum (including but not limited to some oil pressure gauge testing (dp) done by respected member Jim Allen) says oil filter bypass events are rare and when they do occur of short duration.

That is what 'I' take as solid information.

Yes, engine oil pumps have a valve built in that is generally referred to as oil pump 'relief valve". That as opposed to oil filter bypass valve. If the oil pump relief valve not functioning properly, the engine could/would have real issues, including engine failure.

I've seen oil filter canisters split open.

 

[Snagglefoot]

Bypassing in an oil pump is a normal occurrence and nothing to be worried about. If you have an oil pressure gauge watch what happens when your revs rise above 3000 rpm. In most cases the oil pressure increases a bit but not in a linear fashion.

 

[barryh]

Depends on the climate of course but anywhere other than hot, then bypass mode every cold start regardless of oil grade.

When you have a very high flow pump, even the bypass sometimes doesn't flow enough to prevent a crushed filter. It illustrates that a bypass is necessary even if a crushed filter is a very rare occurrence.

 

[Snagglefoot]

As for bypassing in an oil filter, have a look at some of those cheesy You Tube videos where they chill an oil to -40 then pour it from a glass container.

 

[4WD]

Saw these yesterday - probably running 0W8 to stay out of bypass

 

[ZZman]

As for bypassing in an oil filter, have a look at some of those cheesy You Tube videos where they chill an oil to -40 then pour it from a glass container.

I can see that, but for your typical say 0-32 degree winter day the oil wouldn't be that thick would it?

 

[Sayjac]

As a follow up reference to my previous comment about oil filter bypass event frequency best information, I link to comment that also references the aforementioned Jim Allen.

Benefits of Running a Larger Oil Filter? (Cold starts etc)

Hi all, I saw a post recently on here of a small filter that had been cut up. It was on a pretty large engine. I was wondering, would there be any benefits of running an oversize filter? For example, my engine bay has plenty of space for a longer filter. If I could find one with the same...

bobistheoilguy.com

 

[Snagglefoot]

Here is an oil pump for a Chevy LS engine. The spring sits in the machined tube and determines the oil pressure the pump will put out by leaking some of the oil back to the sump.