Oil Filter Change Intervals

The Owners Manual specifies oil changes every 24,000 km and oil filter every 48,000 km. Lets assume that it is too long for marketing reasons and cut everything in half. But still, Porsche clearly allows to keep the same filter for two oil changes. I do not see how it could be a marketing gimmick. But I can see like everybody changes filters at each and every oil change. Is it really necessary? If factory recommends the filter lasts twice as long as oil are they wrong too? And if yes, then why? Does anybody keeps the same filter for two oil changes?

I'm no expert, but I change my filter every time I change my oil, and I usually do it once a year, which is approx. 4500 miles. If you do it yourself it becomes easily affordable, assuming you like to work on your Porsche.

cost of filter - $10 cost of motor - $15,000 I dont know, I think I will buy more filters and use too many, too often and waste a bunch a money on them - I change every 3-4k miles both oil and filter....no exceptions, cheapest thing you can do to keep your motor healthy

I imagine leaving the old filter in makes it an easier plug and play job. Pull cork on oil pan, plug cork back in and fill with oil.

I change my oil and filter every 5K miles

All this very good, its cheap and so on. But it is not my point. To illustrate: It is very cheap to replace say wiper blades every month. So, why don't you do it? Because they last three times or more longer in a perfect functional state, that is why. So, why oil filter then?

Didn't we have this thread less than a month ago?

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What happens if you don't change your wiper blades until they completely don't wipe the rain away.....nothing other than losing your line of site. I guess if you use them down to the metal you ruin a $500 windshield What happens when you potentially don't take care of an engine? Boom. Keep in mind, car manufacturers really don't care what happens long term to a car. Once it is out warranty or about 6 years old, they don't want to see it again, and would much rather sell you another new car. The question is what happens to the guy who owns this car past 20 years later and over 100k miles when the oil isn't changed but every 10k miles and filter changed occasionally? I guess it will take someone to own a car long term using the extended change intervals and reduced filter changes to find out how long a motor will go when treated like that. I know the motors I have been in with long oil change intervals have been pretty nasty. I have heard a lot of dealers are reducing that mileage recommendation on oil changes after opening a few motors up as well. Cheap cheap insurance.

It's like the car being your shoes and the filter is your socks. You can leave the filter/socks on but its holding a quantity of old oil that going to be mixed with the new oil. I guess some just think of the wording being just a filter is involved. You'ld be better off peeing in the oil which would burn off than leaving the old oil in the filter area in there. Figure the quantity of oil involved with leaving the filter in as the different wuantity's listed for oil changes with filter change subtacting the oil change not replacing the filter. I hope this is a simple explanation of one of the ways to look at it.

Here is anothewr reason to change the filter, and look at the old one. https://rennlist.com/forums/996-foru...il-filter.html

I do a 6,000 mile or 6 month interval. Whichever comes first.

Just to add an additional "wrinkle", some of the oil experts knowledgeable in Porsches, like Charles Navarro, recommend changing the oil filer 1/2 way through your oil change interval. I change the oil and filters yearly or about 5,000 miles. And do Used Oil Analysis with Blackstone Labs.

another factor is the Government. There are SOOOOO many rules for car makers and some of them are aimed at "saving the world" - It would not surprise me if the government told Porsche that recommending oil changes at more frequent intervals would break some sort of law - seriously

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Can you change just the filter on a 996 without all the oil draining out? I do it on my BMW because the oil filter housing is on top in the engine bay. Car drives like it just received an fresh oil change after a filter change as there is a lot of gunk build up in the filters. I would recommend checking the oil level after the filter replacement as it soaks up oil.

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yup, loose about 1/2 qt

Thanks for all the answers. Unfortunately, if you refer back to my original post you will see that my real question was not addressed. To clarify: I also change filter with every oil change. But deep in my heart I don't believe it is really needed. Otherwise why would factory recommend filter replacement every other oil change? The argument that they would be happy to see all our engines fail after warranty expires is a specious one. If this was true they would insert many more landmines in their literature. I do not believe the Government goes so deep that it would regulate the frequency of oil filter changes! So, if we assume that the factory engineers are not idiots then the only logical conclusion would be that replacing an oil filter with every oil change, which is 2-4 times more frequent then recommended anyways, is an overkill. Could anybody argue otherwise?

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I think your question was addressed. It's up to you to heed the advice.

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It was NOT my point. I think I should give up... My last try: can anybody show a case when filter stopped working properly after say 5k miles?

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go for it, please post your VIN number so know one gets stuck buying the car down the road

No need to be snide, ivangene. I did not try to offend anybody, did I?

Sorry, Point is I am sure many items CAN go much longer than suggested by people on here, but these people are picky about taking extra good care of their cars and no one would ever skip out on a $10 part as a matter of principal IMO esp when the biggest ticket item repair bill is at stake

I can't tell you why Porsche has an every other oil change recommendation for the filter. One of the reasons to change the oil is to remove all of the dirt particles that are picked up and held in suspension by the oil. If you leave the old filter on, you then mix the clean new oil with a relatively large quantity of dirty used oil. In my opinion, that negates a significant amount of the benefit achieved through the oil change.

I would say the reason Porsche tells you to change your oil filter every other oil change is the same reason they uped the oil change interval to 12k. The EPA and tree huggers.

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I suggested that but it was discarded as unlikely, still I would bet there is an EPA guy reading them and making changes based on "science" rather than myth - just wonder how come the race cars change their oil AND filter every race? seems an over kill

Like most owners who have commented here I change both my oil and filter yearly(I drive less than 5,000 miles per year in my 996). Again, like most owners here I believe it is cheap insurance. However, I believe that any 996 owner would be fine following Porsche�s unusually long oil change recommendations and change the filter every other oil change. Porsche engineers would not have recommended the oil change interval simply to appease the �tree huggers�. I also do not believe that Porsche doesn�t care about the reliability of their cars past the warranty period. After all, their great reputation is on the line. Besides, wouldn�t changing the oil filter every time create more profit for their stealerships? Can someone comment on the practice of Pcar dealerships regarding this matter? Surely someone here has their car serviced regularly by a dealer. The known engine weaknesses and failures associated with the M96 engine have little or nothing to do with the condition of the engine oil. It cannot be proven that RMS, intermix, or even IMS failure is due to unusually long oil service intervals. It has been stated many times by those who have claimed to experience IMS failures that they have faithfully changed the oil early and often in their 996s. I think you would be fine using Porsche�s recommended oil service intervals but I wouldn�t pass this info on to potential buyers of your car. Act as though you are far more knowledgeable on this subject than the Porsche engineers who developed the engine.

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Just like NASCAR spilling gas all over the place. I would wager BIG dollars that all auto MFG where told by the EPA to up the intervals or ELSE. Is there some science behind it? I would say yes. I remember back in the day when Mobil One first came out and people were going all the way to 5k between changes. Snake Oil???

This is a tough call. I want to protect my GT3's motor so I change the oil and filter annually. This means between 2000 and 4000 miles over the past 5 years. On my Cayenne S and Audi 4S V8s I go about 5000 miles. If I thought that oil would last longer I would do so. Every barrel less that we import is good for our economy and the environment. Since almost a quarter of used motor oil is not being recycled (20 million gallons per year in California alone) it may be being disposed of improperly, possibly contaminating our water. One benefit of all those new Volts and Leafs is that they will reduce our potential usage of oil. Regardless of your political affiliation it's hard to believe we would have invaded Iraq if there wasn't oil there.

I have to defend the OP here. We all change the oil and filter more frequently because it removes contaminants that could damage the engine so doing it more often is better than less often. No one has given a science based reason why Porsche reco's every other change on the filter. No one has presented data saying "this is what happens when you change the filter every other time vs. this is what happens if you change it every time." We all just do it because intuitively it is better, it is easy and it is cheap. This is similar to the debates when people ask a Horse Power question and there are a thousand remarks about more seat time. It's not un-useful info--it just doesn't directly answer the question.

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No. Absent some catastrophic failure that has the oil filter torn so it passed unfiltered oil there is no real failure mode. If the filter becomes clogged high pressure oil is routed away to keep the oil pressure at the filter within reason. This likely happens upon cold start on a regular basis anyhow. Not very likely, nearly impossible under all but the most contrived scenario, but the filter's filtering capability would not be significantly affected after 5K miles. Perhaps not after double or triple that. (In fact, given a good air filter a broken in engine with fresh oil and oil kept reasonable fresh would run sans an oil filter with no real harm though would it run as long as an indentical engine under identical cirmstances save with a filter problably not. But as long as the initial shedding of metal a new engine goes through is over and as long as the oil is kept fresh enough so no acid compounds form there is no real big source of 'dirt' in the engine and thus little need for a filter.) If an oil filter left in service for a long time at some point it is possible the oil flow could be restricted some and the engine could suffer from this. I'm not sure if the oil pressure is measured before or after the filter. If after, one might see an oil pressure warning light. But in this case seeing it is too late. If the oil pressure is measured at the filter oil pressure can remain good until the engine seizes from lack of oil due a clogged filter. Or more likely how these engines work the piston oil jets would shut down to insufficient oil pressure and the pistons, rings, piston pins, cylinders would run with less oil and the engine would experience accelerated wear to these components. These components would also run hotter too. Word is the oil jets keep the piston crowns 50C cooler than they would be otherwise. The engine's toast if it seizes or on its way to being toast as critical internal engine components suffer accelerated wear. Heck of a trade off to maximize oil filter service life. Might add the oil filter is back flushed some when the engine is shut off from the drain back of oil. This tends to remove some of the particles of dirt trapped by the filter. These tend to settle to the bottom of the oil filter housing. However, upon engine start these particles can be picked up and carried right back to the filter where they remain until the engine is shut off. Or because some oil is routed away from the filter these particles are carried along with this oil and end up back in the oil reservior where they pass through the oil pump. This does at least two things: It increases the wear of the oil pump and smashes these particles into smaller particles that are of course trapped by the filter but because they are smaller end up being trapped inside the filter element instead of outside and once inside are less likely to be back flushed upon engine shut down. Thus over time the filter passes less oil. The oil filter housing holds about a half a quart of oil and if the filter is not removed this old oil of course contaminates the fresh oil. But so does the old oil in the rest of the engine (maybe 2 quarts worth) and the oil cooler (a quart?). Not enough to really compromise the incoming fresh oil's ability to protect the engine. It does of course lessen the sevice life of the fresh oil some since it starts out with a heavier load/burden of old oil. Frankly when I first bought my 02 Boxster and came across that 15K miles between oil changes interval and 30K miles between oil filter changes I ignored both and elected to change the oil/filter every 5K miles. Some may be ok going longer distances between oil/filter changes but I can see no real reason to follow the owners manual regarding the long interval between oil and filter changes unless one simply wanted to go by the 'book' regarding servicing his vehicle. However, I believe in this case the book is full of it and I simply would not, could not follow that schedule and sleep nights. Sincerely, Macster.

What?!?! Wow 24,000 km and oil filter every 48,000 km! Down here in Oz scheduled services are every 10,000 Km or 12 Months, with a major every 40,000 Km or 48 months. Filter is changed each time. Not nessaseraly a bad thing but quite a discrepancy. Having said that, 10K is quite normal round here, so maybe the stealers just do it to maintain their cash flow Maybe i need to move Stateside???

hahaha. I like to change filters and oils (:

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What adds to the confusion is while the intervals are stated in the owners manual there's a caution about severe usage and what constitutes severe usage is not universally accepted. For instance, a couple of months after I bought my Boxster I bought a VW Golf TDi from a VW dealer just across the freeway from the Porsche dealer. Initially the engine oil service interval was 10K miles. But some few months later VW issued a service bulletin that classified the region in which the dealer was located and in which I used both my Boxster and Golf as a "severe usage" region due to heat, humidty, and particulate matter and traffic congestion. And dropped the oil change interval from 10K miles to 7.5K miles. For all VWs. Porsche just across the freeway issued no such bulletin. The oil and filter service intervals remained at 15K miles between oil changes and 30K miles between filter changes. 'course, as I've mentioned I paid no attention to either VW's oil change nonsense or Porsche's and elected to change the oil/filter in both engines every 5K miles. My point is that in your area due to heat and dust and driving conditions it could be classified as severe usage area and oil/filter services could be deemed needed more often. It is not an attempt to wring more money from car owners but to provide their cars with the service to extend their useful life due to the extraordinary climate/traffic conditions there. Besides, an oil service can't be a big profit center for a dealership. I just dropped one of my Porsches off to have its oil/filter service done. I supply the oil -- Castrol Syntec 5w-50 oil -- and the service department supplies the hardware: engine crankcase drain plug washer, oil tank drain plug washer, filter element, o-rings, and turbo oil collection chamber drain plug washers; and of course the labor. Cost to me? Around $120 to $140 (est. is for $140 but the oil change cost usually comes in under this amount some) which includes not only the hardware metioned above and the labor but also environmental fees (waste oil/filter disposal) and sales tax, oh and the car gets washed. With the service department's labor rate nominally $150/hour that $120 to $140 is not going to push the dealership into a higher income tax bracket anytime soon. Sincerely, Macster.

SO I guess I am left wondering if the EPA is not involved at some lever - why would Porsche intervals be differant between country to country 9and as Macster points out - area to area in some service bulitin. next I wonder if your car was ever in one of those severe usage areas and you have records showing in good faith you had the oil changed per the "book" if it would throw any red flags on re-sale that you didnt follow the local customs? again, its obvious the MFG is not interested in whats best for the car, only what keeps them from being in trouble with big brother or the law suits - follow what you know is right and change these things at 3-5k (opinion)

Macster, I agree that an oil change or two does not bring in a lot of money to the Porsche dealers but given the large volume of oil changes performed by the dealers that money does add up. Also, it is not all about the oil change. Dealerships use regular oil changes as an opportunity to inspect the serviced car and add on recommended services such as brake jobs, etc. This up-selling is the real profit potential generated by frequent oil changes and I would think that Porsche would recommend more frequent oil changes for their dealerships if they were truly necessary. For this reason alone I feel that the factory recommended oil service intervals for the 996 are adequate. How can low end shops like Pep-Boys, Juffy-Lube, etc. offer oil changes at basically cost? They make huge profits by up-selling their oil change customers every service under the sun and many times the customer obliges. Of course, it goes without say that many of these services are performed unnecessarily.

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Resale? I can't help but laugh when I hear someone comment on damaging resale values of these cars. How could the resale value be any lower?

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Are you StrekStrekStrekStreking crazy!

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If you come up with any good ideas for lowering the resale value please put them out there. I wouldn't mind a couple more 911's

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Right with ya, the comment was intended to be a little tongue in cheek. Oil changes will not make them rich quick... However this side of the Pacific, things are defiantly priced differently. There are two dealerships in Melbourne and both offer a set price for a minor service for "modern" p-cars ( read:996-> for the 911's ) at $899 AU, plus you get the up sale if they can... There's no $140 oil changes round here if you want a Porsche tech. The brand is very much perceived as the upper echelon and is priced accordingly. Cost of the materials, consumables, and disposal would take you way over the $140 you guys see... even with the P-car club discounts we get. And as far as 10K Km intervals, ever since i can remember every car I can recall, including dad's were all 10K, and were talking a few years ago. It's only recently the intervals have started to increase. The wife's Audi has a 12,500 Km interval and i believe modern BMW's have a much longer interval. So I think round here at least to some extent it's just the way it's always been! Anyways, I guess Oz is so far away, and economies of scale all play their parts. It's just Sooo much less expensive over there! Food for thought... Cheers Robert

For at least the last 8years Mercedes have a engine oil analyzer that tells when the oil should be changed. I have seen claims on another forum that sometimes the MBZ goes 25,000 miles before needing a change.

Generally speaking its a mess. Recently I short term leased a Peugeot diesel in Amsterdam from a French dealer. It was a brand new car and the FIRST oil (and filter) change was scheduled after 25,000 km ! It performed flawlessly and I did not even open the hood once for 7 weeks and 13,000 km.