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I understand the oil filter's job is to remove contaminants from the engine and that it holds some oil in it from the previous oil; however, is it really necessary to replace this every oil change? Could you get by replacing this every other oil change?

  • If you're going to change the oil but keep the old filter, drain the oil out of the filter too. – user22982 Oct 10 '16 at 16:17

12 Answers 12

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You need to change the oil filter every oil change. In fact some of the longer lasting oils like Amsoil suggest you change your filter out at normal change intervals if you don't use their filters.

The filter is very important in the scheme of things. While the oil may be able to stand up to the longer interval, once the filter gets full enough, it will start bypassing unfiltered oil directly back into the mix. This ensures your engine won't fail outright from oil starvation. It also means you have all of the dirt and particulates causing havoc within your engine. By replacing the oil filter at every oil change, your chances of this happening are far less.

  • Honda disagrees with you, as they spec a filter change for every other oil change. However I agree with you. The trade-off is better filtering on the old filter, versus freer flow on the fresh filter. – kmarsh Aug 9 '16 at 19:07
  • I agree with paul and there is no point of taking risks with your engine that could cost hundreds to thousands of dollars just because you did not wanted to spend few bucks for the filter while changing the engine oil @EvrenYurtesen – Nilabja Sep 1 '17 at 6:26
  • I change oil every 1000 km, I'm using Yamalube for Yamaha Sniper 150 mxi. Am I being expensive? Others told me it could be up to 2000 km. – fiberOptics Sep 10 '17 at 16:19
  • @fiberOptics - Follow what the specs in the owner's manual calls for ... you cannot go wrong following it. – Pᴀᴜʟsᴛᴇʀ2 Sep 10 '17 at 16:30
  • @kmarsh In my experience it's typical for the factory to recommend filter changes every other oil change. Pretty much nobody does that. The "real" standard is to replace each time. – Brian Knoblauch Dec 24 '17 at 13:24
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It is best to change every oil change, they are cheap and no good reason not to.

If you use synthetic oil the oil change interval is longer (usually twice as long or longer) which would mean you don't change the filter as often per mile.

  • Mine are $20/filter. Yanmar diesel using a NAPA filter (Yanmar filters are more than $32 each) Cheap, maybe. – boatcoder Jan 10 '17 at 19:24
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Contra:

I know plenty of people who only change the filter on every second change. The companies of course would insist that you buy lot of stuff from them, so they can't also be really trusted. When i change my oil filter it seems pretty clean however i am sure that i can't measure how clogged/used the filter is.

Pro:

The filter is crucial element of the oil circuit. A failure of the filter is dangerous for your engine, especially when it ruptures on the outside while you are on a highway. The filter is not very costly. When you try replacing it on only every second oil change it could happen that you forget it on the second oil change and it gets used for 3-4 oil changes.

Summary:

Honestly, it is up to you. Given the low cost and peace of mind i would change it on every oil change. For your situation: You could try to open a used one and take a look to see it is clogged or lot of gunk inside. If you use a modern synthetic oil with low change intervals i would think about skipping some change cycle otherwise i would just replace it on every oil change.

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No it's not necessary. But neither is changing the oil either. You can just run the engine and see what happens.

It is necessary if you want to maintain a proper service schedule for piece of mind, reliability and resale points. Changing the oil and filter are meant to go hand in hand.

Let's come at it from another angle.. Lets say you change oil & filter at proper intervals do an additional oil change in between, and skip the filter. Ive been tempted to do so in the past, but I like using good quality Castrol oil. In this case one could argue the filter has not completed a full life's service because the interval was shorter. You might be tempted to think the oil change has done some good, and indeed it would have, but its hard to justify the cost of the oil change when theres still a good half a litre of old oil circulating through plus a filter thats already half used.

In short, when you go to the effort and cost of the oil change, theres no good reason to skip the filter too. Buy your filter online ahead of time and they hardly cost a lot.

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tl;dr: The oil filter literally collects the solid waste of the engine. How long are you going to make this poor car "hold it"?

I understand the oil filter's job is to remove contaminants from the engine and that it holds some oil in it from the previous oil;

Remember, that oil that the filter is holding? That's the worst oil in the whole system. It's the dirtiest and most degraded. The filter is holding onto it, waiting to contaminate a fresh batch as soon as it appears ("here, new oil, enjoy some abrasives that I've collected!". Even worse, a dirty filter stops filtering and is effectively reduced to a dirty bucket that your nice clean oil is sloshing in.

however, is it really necessary to replace this every oil change?

Think of the whole issue as the equivalent biological function. Regularly changing oil and filter will have a direct effect on prolonging the overall health of the engine.

Could you get by replacing this every other oil change?

Will the car run? Sure. Have I changed the oil without changing the filter? Yep. There have been times when I realized too late that I didn't have a matching filter for the engine.

On the other hand, how valuable is this car to you? How many years of life do you want to get out of it? Is an extra 10 minutes of waiting for oil to drip out and a $20 part really that big an issue?

Modern cars have better and better tolerances. Their oil changing frequency continues to drop so the whole filter issue is going to be even less of a burden. Besides, it's a chance to look at a part of the car that you don't normally see....

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The other side of the argument holds more true: You can go without ever replacing your oil if you frequently replace your filter.

Now, at which frequency is different and the oil must be drained before removing the filter, but quality oil should not have to be replaced if not burnt. Some cars with quality oil are known to have recommended this before.

Leave a filter in too long, however, and serious damage can be done if enough debris collects in the oil. Leaving its replacement to every other visit is a risk, but you would likely get away with it.

  • 1
    Could you provide a source for the claim that 'some cars with quality oil are known to have recommended [replacing the filter and using the same oil].' – MooseLucifer Jan 16 '17 at 23:25
  • Oil contains dissolved additives that are gradually consumed. Some may neutralise acids formed by the combustion process. Same story with coolants. – Warren Hudson Aug 13 '17 at 2:58
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In a word, Yes. Leaving the old filter on, contaminates the new oil, with the old oil already in the filter. An old filter's ability to do its job, is already compromised. New oil requires a new filter.

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When I pull the oil stick and it looks almost clear (close to new oil clairity), I'll skip changing the oil filter. If the stick shows semi-dirty to foggy looking; this means the filter is 2Xs dirtier, change the filter for sure.

Have a good day to all!!

  • If the oil is clean why even change the oil then? In that case I would think it actually more beneficial to maybe change the filter. Sadly with a car with over 200k on the original engine my oil seems to become dirty rapidly – John Dream Mar 10 '17 at 15:27
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Bull$hit! oil left in the oil filter will Not contaminate the new oil,otherwise every time you do an oil change a complete engine flush is needed to get rid of dirty oil residue. I've been skipping oil filters on both of my cars with over 180k miles with no problem. I buy the cheapest oil on sale and replace every 5000 miles or yearly.

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    Take 0.2L "dirty" oil and mix it with 5L clean oil, will it stay same if cleanness is conserned? – oryades Mar 30 '17 at 7:50
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How about draining and flushing the filter at oil change time and only actually replacing every second oil change as a good compromise? You could possibly re-use the filter many times and there would be very little contamination of new oil with old.
Remove the filter, have it upside down and tilted to one side, poke a screwdriver blade in to lift the rubber non-return valve and let the old oil drain. Then fill the filter with kerosene (or petrol) via the centre hole and rotate so the kero goes through all the filter fabric. It will backflush through the filter fabric in the opposite direction to the usual and wash away dirt. Drain out the kero as you did the old oil by the screwdriver method. Repeat kero+drain until reasonably clean. Finally allow thorough draining of the kero and prime the filter with fresh oil before re-fitting.

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    this really begs the question of whats your time worth. I suppose if you had some extraordinarily expensive filter it might make sense to try to clean it. – agentp Aug 13 '17 at 22:07
  • There is the "save the planet" consideration. I believe some cars now keep the filter case & just replace the innards. – Warren Hudson Aug 14 '17 at 23:54
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im 58 years old and worked on cars since im 8- yes i grew up in an auto shop. 3000 miles is a good average to go by. if you live in warmer climets a little longer is fine. oil should be changed by hours of running not miles. synthetic oil is better but it still gets dirty. the main reason synthetis is better is that it stays the same viscosity regardless of tempeture. as oil gets dirty and collects moisture it forms an acid ** not good.if you dont agree thats fine pay me now or pay me later...

  • I'm not sure how you can claim synthetic oils "stays the same viscosity regardless of tempeture [sic]"? I'm pretty sure synthetic oil comes in multi-viscosity varieties, just like dino oil? Do you have any references to corroborate your claim? – Pᴀᴜʟsᴛᴇʀ2 Dec 26 '17 at 1:00
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I do change my oil filters every time. I would rather change the oil filter than replacing the engine or overhauling it. What I normally do is to drain the oil, replace the plug, start the engine and run it until the warning light comes on. Undo the plug and leave it for an hour or so to drain the rest. Use a good oil.

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    Running the engine without oil is a very bad idea. – MooseLucifer Jun 16 '17 at 0:10
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    first of all, run without oil, holy #$!! %!, but in any case an anecdote on what you personally do is not an answer to the question. – agentp Jun 16 '17 at 3:13

protected by Pᴀᴜʟsᴛᴇʀ2 Jan 9 '18 at 14:43

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