Oil Changes Every 6 months regardless of miles? Really?

ok, at the risk of starting yet ANOTHER oil change thread, I'm starting yet another oil change thread! But I'd like to ask specifically, " is it really necessary to change the oil every 6 months under the following conditions?" because I think this question applies to a lot of us: If a lovely, well maintained 996, which already has an updated IMS from LN (and the old one looked great when removed, etc.) is driven only about 2,000-5,000 miles a year during the nice weather months, and during the winter it is only driven maybe once a month or less, BUT each time the car is driven, it is ALWAYS started, then driven at least 20 minutes, usually much longer. (Naturally, it is never started in the driveway just to warm up and then put away for fear of being stuck down by the IMS demons!) Under these circumstances, could the DT40 oil (with spin-on oil filter and magnetic drain plug installed) be changed less often? Say once a year or 5,000 miles, whichever comes first? I just find it hard to think that the oil somehow goes bad enough while sitting most of the winter to warrant a change, especially under these circumstances. I understand the "cheap insurance" concept, but it just seems wasteful both in dollars and environmentally (and I'm no tree hugger, believe me you). I'd love to hear from Jake or Charles on this.

There have been other threads on this, it's the acid passed into the oil from combustion , the oil itself or at least the lube package in the oil can go much longer than this but it's the by products from fuel and combustion that get into the oil and can cause problems if they stay in there for a full twelve months !

Dont forget the 52 or is it 53 known failure parts to replace.

Jake has strongly advised me to change my oil every 6 mos and I also use DT40.

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See, that's what I'm asking. If acid is passed into the oil from combustion , then is the amount of time between cycles a factor? If someone were to start and drive their 996 once a week for a 4 hour drive, let's say, versus someone else that did that same 4 hour weekly drive every summer month but skipped 4 months of winter. Should they both change their oil every 6 months anyway? Oh, and sorry for any duplication but I wasn't able to find those threads, not this specific. Yea, I read that, which is why I'm asking.

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My take is if you drive your car only 2K to 5K miles a year is more detrimental to the condition of the car than whatever oil change cycle could possibly dictate its well being. The reasoning is if you let your car sit for days at a time, and during startup, the engine, valves, cam shaft, bearings ..... are all bone dry and that's when excessive wear comes on.

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Maybe, but that's not the question at hand. Plus, driving a car during harsh winters can be detrimental to the car's well being, not to mention my own mental well being! Seriously, I'm trying to ask a very specific question. Think of it this way, Should I change the oil before AND after winter, even if the car is only driven just a few times during the winter (each of which the car is thoroughly warmed up)?

Oil is the lifeblood of the engine. In my mind it is cheap insurance. So my routine is: change oil/filter in Spring before the hot months set in; change oil in the Fall before the cold months set in; regardless of miles. I simply use 2 x 5 quart Mobil 1 0W-40 containers and a new oil filter each time. An oil change probably runs me about $55/oil change. I don't drive as much as I used to, so miles on the car per year are getting lower. I don't go all fancy on an oil change, just basic oil/filter change. BTW, I have 142K on the car and everything runs perfect.

I think there are several conditions to take into account: not just the acid from combustion climate, how wet is the climate, which can affect how much condensation gets into the oil. what kind of oil is being used (if you change the oil every 6 months, does it make sense to use a lesser oil?) what are the additives in the selected oil that combat the acid or other forms of degradation. who is providing the recommendation, is it Porsche, or an after-market parts vendor, or your favorite experienced Indy racing - even road racing your favorite mustang at the red light. what data is available? is there data that shows how much acid builds up after some time, is there data that indicates what concentration of acid in the oil might cause a problem. time vs use: is there data that shows the degradation of the oil over time from use vs from elapsed time just sitting there. opinions, everybody has one, And then the big one: it is not black and white, your choices are not limited to either "every 6 months or every year", its a continuum. Hey, you can pick 8 months, or 10 months, or 1.5 years, or 5,000 miles, or 8,000 or 15,000 miles.

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I was sort of getting to this. If following LN's recommendations, which I am, then it's DT40 oil. Which unfortunately, is $140 for a case of 12. (BTW, I just ordered another case of DT from LN, but it pains me to let $140 of oil go down the recycling drain after a few hundred miles!)

I am no expert but do know a few things to consider. The IMS bearing is part submerged in that oil and probably the chain, guide and other parts and some of them are plastics.

I guess another question is, if you put in fresh DT40 in October and put the car in storage. Take the car out in Spring (never fired up), is the oil good from that point for 6 month or 5000 miles?

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Very good question. That's the same boat I am in personally. I change my oil before the car goes into storage last fall and just pulled it out yesterday. So the car will see about 6 months of run time (but 12 months in service) on the fresh oil, however, it sat with clean oil all winter and I never once started it or ran it. Idea is when you do run it, that you get it hot enough to vapor off any moisture. Dirty oil (combustion byproducts) plus moisture = acid, which causes corrosive wear and reduces the TBN (total base number) of the oil, basically using up it's life without even seeing operation.

Under the circumstances you describe, changing your oil one time per year is perfectly reasonable. Or every 5,000 miles whichever comes first. If you read these forums long enough someone will be convinced the world will end in a shark tornado if you don't change your oil weekly. Someone else will say they have driven 500,000 miles through rain forest only topping off their oil as needed. It's your car, change it every month if you like or don't. I change mine one time per year or every 5,000 miles. My car has 123,000+ on it and runs perfectly. I don't believe there exists a car forum with more paranoia over maintenance or bearings than 996 forum. It's straight up nuts. My 20+ years driving Porsche brand has taught me this, do the maintenance that's needed, fix the stuff that breaks, and these cars are extremely reliable in general.

So it sounds like the ideal scenario is to change the oil at the end of the season (so it's not sitting all winter with dirty oil, which makes sense). And then change it every 5,000 miles or 6 months OF SERVICE (not so much 6 months of idle time). Does that sound about right? The only tricky part is if the car is driven more in the winter, then as someone suggested, it becomes less of a hard timing thing. And when in doubt, change it out!

Yes, certainly change it before it goes into storage so the parts aren't sitting in bad, acidic oil. If the car is stored in a high humidity area and only started infrequently to keep oil in the various nooks and crannies, then you want to change it when it comes out as there will be gasoline "wash" in the oil since it did not get hot enough to vaporize it out. $140 a case for DT40 isn't really that much more than a case of any quality motor oil. Another option is to move some place where you can take your Porsche out every day and drive it, like I do

Even though it is directed to racing applications, you might find this helpful..... http://www.drivenracingoil.com/docs/...cingOil101.pdf

I'm surprised no one has raised the issue of getting used oil analyzed as part of their oil/filter change regiment. Everyone has an opinion; while few have data. relinuca

ALCON, Just my 2-cents I have a 99 Boxster that is my daily driver. I purchased it in Sep 09, with 104,000 mile. It now has well over 312,000 miles. I change the oil & filter every 10,000 miles (that is more often than what Porsche originally called for). I've used Royal Purple and Mobil 1 (10w40 European, 10w40 High Milage, 15w50). My recommendation is to just drive the car, drive it often. If you do not drive it often then change the oil & filter at the end of each driving year (if you live in the North) or once a year. I also have a 2000 911 and I treat it just as I treat the Boxster, I just don't drive it as much as the Boxster. MNC-I

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I'd love to hear more about your Boxster. Over 300K miles is fascinating...what has happened along the way? Any major issues? Any tips/tricks?

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This is the perfect response, thank you. Changing oil every 6 months is meant for folks that don�t understand under what conditions would possibly exist to require such a ridiculous interval: those who start their car every week, don�t drive it, let the engine idle for 10 mins to �warm it up�, then turn it off. Repeat 20 times. Now the engine is filled with water. The other reasons would be tracking or accumulation of 5,000 miles in 6 months.

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I concur. When I hear people talk about starting their garage queens to warm them up and then put them back, I cringe.

We mandate 6 month/5k mile oil services for all of our engines, despite the oil that's being used.

Jaycote, http://986forum.com/forums/search.php?searchid=3242418 As requested, here is a link to were I am most active. These should depict my posts to the 986Forum MNC-I

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Wow, that is some serious miles! incredible! Can you outline what things you've had to fix or address along the way? And if we are talking about oil, I believe Shell still has a rebate on Rotella T6 5w40 synthetic, which gets great reviews. Works out at about $36 for 10 quarts (2.5 gallons) which is really cheap. I run it in two of my cars.

When I start my cars, they get driven, especially the GT3 hogging the garage. Still, I do oil change (I'm liking Motul at the moment) 1x year or 5,000 miles - whichever occurs first. My indy tried to sell me on every 90 days. I got a new indy after that stunt. Do what makes you happy.

Chris(MA)Jaycote, http://986forum.com/forums/search.php?searchid=3242418 Check out my postings on the 986Forum. Just about everything I�ve done to my Boxster is addressed there. Two of my biggest gripes about the Boxster are the weak water pump and stupid AOS. I spent a few days under the car replacing the pump and thermostat only to put the wrong bolts in the wrong holes. I ended up taking it to my Indy and purchasing new gaskets and a new pump. I also replaced the alternator, sort of, I got the old one out but could not get the new one to properly lock in place. I also had to take that to my Indy down the road. I did have one success story. I had a radiator leak on one side. So I went to my go to guy Woody. Woody owns Woody�s Auto Parts LLC out of Bastrop, Tx. He buys wrecked Boxsters and parts them out. He does not sell cars, unless it is for Spec Boxster racing. He charged me $50.00 for the radiator as I put it all back together and started filling up the cooling system the other radiator started to leak. So back I went to Woody for another $50.00 radiator. Replaced that one and refilled the system and everything went super OK. I change the spark plugs, plug tubes, and coils along with oil & filters myself. I�ve done complete brake jobs minus replacing the fluid. I take it to Firestone for brake fluid flushes. I�ve had the oil sending unit replaced it was leaking badly. My advice is to one get your hands on a Bentley Manual and a knowable mechanic. In Austin I recommend TPWS Inc. on North Lamar Blvd. I was taking my car to a high end mechanic right down the street from them mostly because of the curtesy car available. Well one day my top stop working. It would not go up it stayed down. I took it to the high end mechanic and got the need new motors etc. at a cost of over $2000. So I told them to disconnect it so I can manually raise & lower it. I got the no can do. So they permanently put in the up/closed position. I forget what it cost me. My next move was to TPWS Inc. The mechanic there had a 986 like mine. I told him of my problems and within 30 minutes he had determined nothing was wrong with my motors. Within 1-hour I was back in business. I paid him more than his one hour rate and left very very happy. I cannot say more than enough good things about TPWS Inc. I buy my oil based on rebates. Here in Texas, I go to Walmart (big box store) and purchase the 5-quart jugs at anywhere from $23.00 to $25.00 per jug. I time my purchases with the yearly Mobil 1 rebates (e.g. $12.00 rebate for each 5-quarts purchased). So I time it to get $24.00 back from my two jug purchase. Beware of all the oil threads and the IMS threads. At one time I was on this I got to have all this Zinc additives in my oil. I�ve decided to go in the future with High Mileage Mobil 1 or Royal Purple High Mileage in my 312,000 mile 986. My 2000 911 will continue to get Mobil 1 0w40 European until it reaches 200,000 miles. I am also considering going to the modern screw on metal oil filters for my 911. MNC-I

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Thats why low mile 930 and 993 turbo's are worth more than your house!

" .Two of my biggest gripes about the Boxster are the weak water pump and stupid AOS. I spent a few days under the car replacing the pump and thermostat only to put the wrong bolts in the wrong holes. I ended up taking it to my Indy and purchasing new gaskets and a new pump.I also replaced the alternator , sort of, I got the old one out but could not get the new one to properly lock in place. I also had to take that to my Indy down the road." "Stupid AOS"...

+996 on yearly oil, I don't really get near the 5,000miles/8,000kms

Does this alleged oil acid only attack Porsches? Why wouldn't this be a concern for all automotive engines? I think we are being a bit paranoid here.

Yeah. And I always wonder how many are aware that you never really change the oil in a 911. As far as I know they all, from the first air-cooled's to the latest 991, have total oil capacity of about 15 or more liters. That's what it takes to fill everything, oil lines, coolers, the old reservoir's and the new foam pots, engine galleys, the works. But the most that drains out and gets replaced in an oil change is 9 or 10 liters. So about 2/3. In other words about 1/3 is always old oil. What makes me wonder is in all the worrying commentary about the dire effects of old oil never ever- ever!- has even one person said you really need to do TWO changes back to back just to reduce the old oil to 10%, or drain and flush all the oil lines and coolers to do a complete oil change. Never once. Personally, my preference is to drive with Mobil tankers hooked up leading and following, with fresh Mobil-1 coming in from one and going out to the other. But only with trucks dispatched the morning of my drive. And I check the manifest for date of manufacture. Nothing over 24 hours or its back to the barn! Did I win?

My new year's resolution was to learn how to work on my car myself. I was having my oil changed on a mileage-based interval, and not a time-based interval. I can tell you, the first time I did it myself, my oil smelled very rich. Yeah, the filter was perfect. The oil was not too toasty. But it smelled like gasoline. I've been on this same interval for 3 years now, since I've gotten the car, and my mechanic has never brought anything like this up. Suffice it to say I'm going to subscribe to the time & mileage doctrine from now on.

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I�ve done that for engines I�ve inherited that have been neglected. Change the oil, putting in an additive for detergent, ran the engine pretty hard while driving it, then change the oil again. Otherwise, and once that�s done, never again needed.

I've driven (thru April) 2776.3 miles on my 03 C4S, and probably had the oil changed at around half of that. I've been reading these threads and on FB groups as I have a Tip and original IMS, but my indy didn't tell me anything about the 5k mile interval, just that the oil looked great and there were no issues and unfortunately, the prior owner stuck more to the 996 service interval checklist of about 9k miles per oil change and servicing wasn't done at an OPC. But, I haven't had any issues in now 7 months and those almost 3k miles of driving, so I dunno. I'm thinking about an annual service, as I don't truly daily drive it, but drive it enough to where it's getting used so I figure an annual service will get me close to 6-6.5k miles, and for me that's close enough to 5k to feel comfortable about it. Next time though I plan to buy a nicer and full maintenance-record example, with stamps and all, so I may be more thorough about this kind of thing but for now it doesn't keep me up at night and I love driving this damn car!

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^^You should also have your injectors checked/replaced - it's possible you have at least one and possibly more that are leaking fuel into your cylinders. This is very BAD for several reasons...(not just bad mileage...do a forum search for more info).

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See, that's the curse of the modern 911. They're supposed to leak or burn that leftover 1/3 between oil change intervals, but alas now the oil has a pesky habit of staying in.

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Frequent oil changes are one of the cheapest things we can do to these cars. Anyone who cites the environment should pause and consider the carbon footprint of having an extra sports car around purely as a luxury.

If once a year is good, twice a year is better. Heck, monthly for 996 owners is best.

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Thanks for the laughs!