20 K NO WAY!!!

I've been running Mobil 1 in everything I own for at least the last ten years. I own a commercial fish boat the cost of a new engine in that would make a Boxster engine look cheap. We run Mobil 1, my partner was not a believer. I said change to Mobil 1 15-50 and just listen to the difference in the motor. He is now converted! We do oil analysis cuz it's a lot of oil. Just change the filter at the service interval. Last oil analysis we were good for another 500 hours at least.

My old Windstar 210k miles on Mobil 1 10 k changes still runs great and does not use oil. And it's the notorious 3.8 liter.

I'll change the Boxster at 7.5 K intervals and not worry about it.

SD987: I'm up in Oceanside don't get the Box down to SD much so wasn't me. I will get some good pics to post, I like the color comb. but it was my wifes good taste. I looked at a 2 tone interior boxster at Pioneer, did you buy yours off the lot? I liked the two tone a lot. We got our's in late June. I will tell the whole story here one of these days with pics.

Thanks for the advice guys. As to whether Porsche or others are more qualified to make recommendations, I will have to take all these recommendations with a grain of salt. As most people do not believe Porsche in their oil change interval, I think the same mentality may be true on soft break-ins. A lot dogma that is in place today is based on experiences from many years ago and ideas which were valid for that technology may not be true today, but is perpetuated because that is the way things were done for so many years. Also, I would like to know where the 4200rpm limit originated from and how that magical number will somehow decrease engine wear as compared to a limit of 5000rpm, or why not limit to 3800rpm to decrease wear even more? I don't claim to know what is right or wrong as to how to break an engine in, but I do think that these long-standing traditions need to be reevaluated every so often to see if they are still valid or merely relics of years long passed.

"As to whether Porsche or others are more qualified to make recommendations, I will have to take all these recommendations with a grain of salt. As most people do not believe Porsche in their oil change interval, I think the same mentality may be true on soft break-ins."

Porsche engineers ARE qualified. No one in their right mind would question that. What MAY be questioned are Porsche's motives behind certain recommendations. The break-in is a no brainer as Porsche doesn't gain anything by being dishonest about it. The oil change interval, on the other hand, is different as Porsche DOES gain by recommending a longer interval than the one it knows to be better for the engine. Thus, the "optimal" interval for Porsche will always be longer than the one that's optimal for me. For oil intervals, there's no question that shorter is better. So buy insurance and do it more often. You can't go wrong with that.

Z.

I would concur with this view.

On the Oil Change issue, I know of NO OTHER can manufacturer in the WORLD that recommends 20K miles for an OCI. A few will use a oil minder and get you to 13-15K or so, but that is it to my knowledge. It is noteworthy that Mercedes is one of those makers and their record of late on longevity is hardly a ringing endorsement.

Moreover as I indicated in a previous post, other than Red Line, I have never seen a used oil analysis that provided comfort beyond say 10-11K miles.

And that was with the OLD M1 formula. The new formula provides even less comfort.

Hi GmanMD, I do not know the break-in procedure for the 986. But for the 987 the RPM recommendation is below the 4,200 range. Maybe this has something to do with the VarioCam. Even though VarioCam is active at all engine speeds and loads.

Perhaps I wasn't clear enough. Actually, as I said, Porsche DOES gain by recommending a longer interval, as it lowers the perceived cost-to-own (maintenance costs) of their cars in the eyes of potential buyers, thus making them more marketable and competitive.

You were clear (but thanks for using small words), however you're overestimating the marketing benefit of the oil-change interval.

I can think of few automobile purchases more impractical than a convertible two-seater, particularly one costing 50-70k. If you were talking a family-toter perhaps, but I suspect the number of 987 buyers whose purchase decision was influenced by a 20k service interval = 0. Especially, since the majority of car buyers don't even crack open the service manual until after the purchase.

As I mentioned before, your theory also doesn't shed any light on why Porsche picked 20k. The marketing benefit could have been achieved by selecting 16k, or 17.5k, and yet they made it 20k. Think the marketing guys said, "hey, let's go with 20k cuz it sounds like alot"? Perhaps, perhaps not. As I said, I suspect 20k is actually understated.

But echoing the obvious point made by Bruce, to each his own. If you want to go with short oil change intervals because, Bob the oil can guy's website says so, or because your uncle Gus maintained his car like that and swore by it, than go for it ! It's your car, your money. If I want to believe that Porsche and Mobil one's engineers think 20k is the appropriate interval for a 3.2 liter engine with 10 quarts of synthetic oil, I fully accept the consequences. I don't think either group is going to convince the other.

Not to put too fine a point on it but M1 never said that it's 0W-40 oil is good for 20K miles. They tell folks to follow their manufacturer's recomendations.

Of course, that way, they are off the hook, as it is Porsche's recommendation.

It IS notable that for its PREMIUM oils, ie the ones that are more expensive than 0-40, they say you can go to 15K MAX.

Again, if you really want to drive around with oil that is OBJECTIVELY shot for say another 8K miles, hey, more power to you.

If you you don't buy my line of reasoning, spend a few bucks and send a sample of that 20K oil to Blackstone.

You may get some religion!

Hi,

7500mi., 15k mi. or 20k mi. - it's your car and your money. No one ever hurt their engine by changing the Oil early.

But, for those in the 20k mi. Club, consider this - that Change Interval assumes Ideal Driving Conditions.

Have a K&N, S&B, True Flow or other gauze type filter (Oiled or Dry)? - Shorten the interval. Live in a dusty (include Expressway driving - terribly dusty environment) or Rural area (or travel through one)? - Shorten the interval. Commute in Stop & Go traffic? - Shorten the interval. Short drives, under 10 mi.? - Shorten the interval. Weekend only driver? - Shorten the interval. Drive fewer than 20k mi. in a year? - Shorten the interval. Live in a Hot Climate? - Shorten the interval. Live in a Mountainous or Hilly region? - Shorten the interval.

No one from Exxon-Mobil, Porsche or even AAA will dispute this. How much should you shorten the Change Interval? Well, it depends on how often or severely you encounter the conditions described above - and we're back to debating...

Happy Motoring!... Jim'99

Something to keep in mind that over the years the engine design has evolved with different materials and higher quality standards. The old cast iron block and heads are a thing of the past. So much research and development has gone into using the right materials and tolerances combined with varying FEA/CAE and countless tests in dyno labs. The same thing can be said for oil. It's not the same stuff that use to come out of a can that you had to puncture the top with a fancy spout.

I will confirm that when I worked in the dynamometer lab for one of the largest auto manufacturers in the world, most of the new engines had zero problem going to 10,000 miles with non-synthetic oil. This was measured via oil analysis, consumption and various life cycle testing. Do I remember the specific data... no (got out of powertrain as quickly as I could)... but I can confirm that this was the state of oil changes 5 years ago with an OEM...

Disclaimer: When I say engine design this includes the supporting systems and not just the block and heads.

BTW - I change my oil at what I think are reasonable levels. My daily driver is changed at every 3k because I do a lot of stop and go and I use non-synthetic. My Boxster will be changed once a year. Do I need to... probably not but I sleep better at night for some reason.

SD987:
As I mentioned before, your theory also doesn't shed any light on why Porsche picked 20k. The marketing benefit could have been achieved by selecting 16k, or 17.5k, and yet they made it 20k. Think the marketing guys said, "hey, let's go with 20k cuz it sounds like alot"? Perhaps, perhaps not. As I said, I suspect 20k is actually understated.

They had to pick A number. My point is that the equations that they used to come up with that number have variables (marketing, etc.) that I personally don't care for. I only know that those variables will only make the recommended interval longer than what's optimal by my equation -- by how much, I don't know (unknown = risk).

Adding to this MNBoxster's list of varying driving conditions only compounds the risks and the unknowns. Some people take those risks head on and don't buy any insurance -- and many of them may come out financially ahead in the end. For me, the more frequent oil changes are cheap insurance in light of the risks we just discussed.

Z.

An oil change is a great value for the "feel good" factor! Don't you guys feel great when the oil is brand spanking new! Everything just feels better! Kinda like a car wash!! :) Or a fresh coat of wax. Or a.......

I misspoke earlier and I do agree that Porsche engineers are qualified. However, I do find it interesting that everyone is eager to state that the oil change interval is inordinately long but we should accept their break-in advice. Now some of you have pointed to studies that support your claim that oil is shot by 10k or so and with that, I would then agree with you. As a doctor, I am going to have to put this into medical terms: the big push today is what is called "evidence-based medicine" where your practices are in line with PROVEN practices supported by medical literature. You would be surprised how many physicians out there have certain ways of treating conditions that are not in line with the literature, but are based on 1 or 2 cases that went bad (or very good) for them in the past and they changed their practice patterns based on this. What I want to see is evidence that hard break-ins are detrimental to the engine and how they came up with the 4200rpm limit (ie. whether that be from VarioCam kick-in). I do not accept "because they say so" as these recommendations may be holdovers from years past. They have lowered the break-in period from 2k to 1k and that just may be a push towards breaking those old ideas but they cant seem to really "pull the trigger" all at once.

Just my $0.02

Great Thread!!

I think the key to this discussion lies in a couple of the replies.

1. Y.M.M.V. Your mileage may vary. Oil change intervals must be adjusted according to the severity of service.

2. Everything is breaking in, not just the engine. I do believe I will do my transmission fluid as well b4 10 k comes up.

Look at the huge business's (jiffy lube et all) that uses the 3 k interval to drive their business. To me, 3k is a holdover from what, the 1940's or something. Wild guess there but that interval is pretty much BS to me.

Oil's whether they be synthetic or dino have changed and improved by orders of magnitude from the time that the 3K interval was the standard. As has engine construction. Yet somehow the old myth of 3k is still with us.

Our company cars are managed by GE Fleet Services (not the Boxster) and they still recommend a 4,000 mile interval service between oil changes. I would think GE has a LOT of data to suggest this is the best recommendation (risk vs reward). I have seen other fleet services that have a 5,000 interval. So, I don't think that Jiffy Lube is too far off, just a little more aggressive and profit motivated.

"Oil's whether they be synthetic or dino have changed and improved by orders of magnitude from the time that the 3K interval was the standard. As has engine construction. Yet somehow the old myth of 3k is still with us."

Most DINO oils are gone by 3-4K miles, at least as tested.

Most "fake synthetics" like Castrol are gone at 7-*K

M1 usually makes about 11K or so till it is shot.

Red Line normally can make 13-15K tops.

I certainly do not advocate 3K changes with synthetic oil.

This is all a long way from 20K.

Reminder. Porsche is the ONLY manufacturer to make this recommendation. Are we to believe their engines are that different than others?

Hmmmm!

If GE Fleet is using normal DINO oil, I think the 4-5 range is good. Keep in mind, they only really care about costs while they have the car, which is short range.

I assume our Box owners are thinking longer term but who knows?

"You would be surprised how many physicians out there have certain ways of treating conditions that are not in line with the literature, but are based on 1 or 2 cases that went bad (or very good) for them in the past and they changed their practice patterns based on this."

That's not only surpising (to me) but downright scary. Don't MD's study the scientific method and statistics during the 20 or so years they spend in school? I would also periodically (every 4 yrs or so) test EVERY MD on how up to date they are with the latest literature in their field of specialty and medicine in general. Only then they should remain certified to give life/death advice.

To continue your MD analogy, the same way every MD doesn't give out copies to patients of all scientific papers that made him give his recommendation, Porsche engineers don't include all their lab results, equations, and tests in the Porsche manual.

Z.

My mazda dealer just said change the oil every 3k 3 mo when the owners manual says ever 7,500 mi. I think I will stick to the manual. 3k 3 mo seems to be an old standard which some live by to either gain more $$ or out of pure ignorance.

Yes it is scary, that is why you should choose your doctor wisely (and that is a whole other discussion on how to do that). They do get periodically tested but that doesn't necessarily translate into their management of patients. You are correct that those papers aren't given to patients, however, they are available for anyone to read at any time as they are on the web (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi if anyone is interested). And one thing we have seen time and time again, is that ideas need to be revisited when new technology and treatments are available. And many ideas thought of as heretical at one time are now accepted as fact (ie world is flat vs round, etc...) I would love to see if there is any published data about the break in period and how old that data is. I agree with everyone about the oil longevity and people are able to cite studies on those, yet no one has access to or knows of studies done on engine break in.

One thing I think that is overlooked in these discussions is the fact that our cars hold twice as much oil as US cars that recommend 5000 to 7500 mile oil changes for normal service.

Our motors are smaller than V8s, run cleaner, and have twice as much oil, so the additives last longer.