Is it necessary to replace an oil filter every oil change?

Question

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?

Answer 1

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.

Answer 2

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.

Answer 3

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.

Answer 4

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.

Answer 5

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....

Answer 6

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.

Answer 7

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.

Answer 8

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...

Answer 9

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.

Answer 10

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!!

Answer 11

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.

Answer 12

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.