When To Change Oil
 

When should you change the oil on a new 987S? The owners manual says 20,000 miles or 2 years. That seems like an aweful long time! I have always changed my oil on other new cars after the first 1,000 miles. Is this over-kill for a Porsche?

I think the first question to be answered is, how long am I likely to keep this car?

If it were me, this is how I would approach it:

If I were pretty sure I would dispose of this car within the warranty period or shortly thereafter, I would simply follow the owners manual.

If this were a long term car (however you define it) I would do the following:

1-Change the oil and filter at 1000 miles.

2-The change the oil and filter at 10K, 20K etc.

Of course, you want to use M1 and quality oil filter, pref. a M1 filter.

Good luck!

:cheers:

Thanks Brucelee, I agree with you. I will be a long-term keeper. But why change the oil at the 1,000 mark?

Old habits die hard...I too am from the school of 3000 mile oil changes but I think this approach may not be necessary in all situations.

1. If Porsche engineers felt that following a more rigorous oil change procedure would be better, they would probably recommend it. There's no financial incentive for them to increase the interval, but there certainly is for the them to decrease it, e.g. an increase in dealer service visits, improving the longetivity of the engine, thereby reducing engine failures and warrantee replacements and indirectly improving the company's reputation for reliability. If they set the intervaly at 10 or 12 thousand miles, people would still say..."wow, that's a long time"...but instead, they set it at 20,000. There's probably a great deal of thought and testing behind it.

2. Not many cars run synthetic from the get-go. I don't think that many boarders are experts on engine oil viscosity but I think we can all agree that synthetic does the job longer, it's just a question of how much longer (see point 1). We've all heard about big rig trucks that run synthetic with amazingly long intervals, and while we're not driving semis, synthetic oil is pretty amazing stuff. Conversely, I'm highly skeptical of "seasoned" pros who drain the oil and say..."wow, that's been in too long". Used oil looks alot like used oil, and irregularity such as discolored traces are indicative of other engine problems not necessarily the amount of time it's been put in service.

3. Porsche engines hold/require an amount of oil greater than the amount normally held by engines of similar displacements. Whether this translates into better lubrication is beyond my knowledge, but it certainly would infer it.

4. I think that how one drives more directly factors into oil life than months/miles elapsed. For example; driving at high revs, climate, dusty conditions, running the air conditioner alot are all variables that are difficult to quantify but definitely have an impact. Auto manufacturers attempt to determine an "average" amount of engine use (or abuse) and appropriate service intervals. Your experience will obviously vary based on your conditions, but I assume that manufacturers err in the direction of caution. Quite possibly the oil interval under ideal conditions could even be longer than it is set at.

5. IMHO people misunderstand break-in. They attribute improved "smoothness" to an "eroding" effect between moving parts, when I believe it's more accurately attributed to a "settling" effect of seals etc. Keeping in mind that the engine oil actually serves as a lubricating film that keeps parts from coming into contact with each other. The expectation that changing the oil after 1000 miles will rid the oil of particles that have eroded is unrealistic in that such particles would actually be highly undesirable, not to mention unlikely after such a short period.

But...changing the oil is only @125.00 or thereabouts, and as they say it's your money. If it gives you peace of mind, then that's a pretty small price to pay. I personally plan to get my book stamped on schedule.

During the break-in period your engine is "getting used to running". As the parts mesh and rub on each other, tiny pieces of metal that don't meet perfectly come off and go through the oil system. Changing the oil at 1K miles gets that stuff out of the system so it can't come loose and go through the engine again.

I'm with Brucelee on the 10K miles. I tell my wife when she hits the 10K mile marks to let me know and I change it after that, but always before the 15K mile requirement.

As for why the interval is so long, it's because it's pure synthetic from the beginning and lots of it like SD987 said. With twice the oil of the normal engine out there, it takes a lot more contaminate to dirty it up and break it down.

One thing I'd disagree with from the manual. If you put less than 7K miles/year on the car, change it annually. Sitting destroys an oil worse than driving due to moisture in the oil reacting to make it acidic as it sits.

Hey Brucelee: Is there a M1 filter for the Boxster? I've never seen one but I'd love to use those instead of the OEM.

On the question of the M1 filter for the Boxster, I have to confess that I have never purchased one (being that I am a dealer, I simply use Porsche OEM's when I do my service).

Having said that, a quick call to Mobil will inform. Sorry that I don't have this info direct.

Re: How long is the oil good for, I would disagree with the statement about the 20K miles being fine, Porsche wouldn't recommend it if it weren't fine etc.

I have seen many studies on the long term quality of syn oil and my take on it is as follows:

M1 and Amsoil start to get "tired" or dirty at around 10K miles. They CAN be refreshed by changing the oil filter at around that mark. IF you change the filter, the M1 seems to be fine until around 16-17K, when it could use another filter change or to get it out of the engine.

Frankly, to enhance the chance that my 12K dollar engine will last a goodly long time, I would simply perform an oil change and filter at 10K and not be the guy who is experimented upon.

If you buy your oil at Wally world, you pay around $40 for oil, $18 for filter. I have a guy who charges me $15 to do the change.

Cheap insurance for sure.

IMHO.

PS-the post above nails the 1000 miles change recommendation. I have seen many oil changes on cars at this mark and there are tons of metal shavings coming out. Don't want this in my long term Box for sure.

A guy at a Porsche dealer told me that they dyno the engines in Germany for 500 miles, drain the oil, and refill before shippijg to the USA. Is this true? That's why I thought you don't need to do the 1,000 change with the Boxster.

Sorry, I don't know that one.

There is (or at least was) an incentive for car companies to set longer oil change intervals, from the EPA or similar forces in governments everywhere. Back when we had effective CAFE regulations and the like, there was great pressure to reduce the amount of not just gas but also oil consumed. An easy way to do this was lengthen change intervals. The same folks that figured out it was cheaper to not fix the Pinto gas tank problem probably also were able to model when the engine would fail, on average, at change interval x+y%, so the car company execs could please the EPA. I'm sure it was/is targeted to be at some comfortable point past the factory warrany period.

I experienced this the hard way with my first "bought new" car... an '84 Honda CRX. Factory change interval (just extended at the time) on that was said to be 5K miles (conventional oil). I had previously always changed at 3K on all the used cars I'd owned before, with good long engine life. Following the 5K on the Honda got me a smoker by the time it hit ~70K miles.

I'm back to a religious 3K interval on my conventional oil cars since and they've all lasted well past 100K with no oil consumption. I'm doing every 10K or min. yearly on the Boxster with M1. With the oil being recycled now, I'm not worried that I'm ruining the planet with this practice - quite the opposite. By having the car last longer, that is one less vehicle that needs to be made as long as it lasts, saving energy and other resources consumed in the mfg. process. And of course, fewer steep new car depreciation cycles for my wallet, too. :cheers:

I would think there is virtually no chance this is happening.

Conventional DINO oil IS shot at 3K.

I use M1 in my wife's Subaru and change it at 5K.

Seems to work fine.

:cheers:

Hi,

There is some pretty good evidence that changing the oil at the 3k mi. interval actually increases wear to the Engine and it's internals.

I know this seems counter-intuitive, but Engine wear actually decreases as oil ages. This has been substantiated in testing conducted by Ford Motor Co., ConocoPhillips, and reported in SAE Technical Paper 2003-01-3119.

What this means is that compulsive oil changers are actually causing more engine wear than the people who let their engine's oil get some age on it.

To add some perspective to this, I agree with the 10k mi. or annual (if less than 10k mi.) oil and filter change. Additionally, most of the dirt and particles which pass thorugh your Air Filter end up in your oil. If you live in (or have driven extensively through) dusty areas, or use a K&N Type oiled Filter, you should shorten the change interval. Hope this helps...

Happy Motoring!...Jim'99

Jim 99 is dead on with his post.

I too have seen this research on engine wear right after an oil change.

Regarding the factory run-in of the motors Yes, Porsche runs every motor on an engine dyno prior to installing it in a car. As for the number of miles, that's unknown but they do run it through a computerized "break-in" then make power pulls to confirm output. The oil is then drained and replenished when it's finally installed in a car.

That would pretty much eliminate the need for a 1000 mile oil change.

BTW, if a motor doesn't make it's spec rated HP it's torn down to analyze why. Because of this continuing analysis they have very few motors that don't make the grade.

Here's a quote directly from the Porsche website:

The following hot test is the final step in the engine production process. The engines are first of all heated up to operating temperature and then subjected to a functional test including full-throttle testing. Information in the form of up to 220 parameters is generated in this test of around five minutes' duration.

This ensures that Porsche's high quality standards are also met in the area of engine construction.

" generated in this test of around five minutes' duration."



With all due respect, the text reads like a PR piece from Porsche. Having seen the metal shavings from a 1000 mile oil change, I would keep doing them.

5 minutes? Give me a break!

:cheers:

Hi,

You'll excuse me if I'm somwhat underwhelmed. Porsche may in fact run up their engines to confirm performance specs.

Too bad they don't also perform Quality and Durability tests, especially with respect to the RMS and Intermediate Shafts. These persistent Quality failures (prevelant through the entire 986, 996 model runs, with no apparent improvement through the years) are unconscionable for a Company with the past reputation for reliability. I mean, even Kia got this one right!

Happy Motoring!... Jim'99

Jim,

I'm not saying that they don't have their problems and I don't want to get into a pissing contest regarding Porsche's QC.

The question at hand was regarding factory specified oil change intervals and the discussion surrounding the factory's run-in proceedure. Here there can be no question, Porsche specifies the oil change intervals, including the initial change, based on their analysis of test data. If you choose to deviate from that formula then you do so at your own risk. As evidenced by some published scientific data more (sooner) is not always better.

I personally never bought into the 3000 mile change intervals. Those have been engrained on the population by the Jiffy Lubes of the world for the sole purpose of boosting their bottom line. No major engine manufacturer ever specified those intervals for normal driving conditions.

I think if you were to get access to the engineering data within Porsche you would find that even with the 15,000 oil change interval the oil's ability to protect the engine is well within spec. I wouldn't doubt if their data shows acceptable wear well past 20K intervals. Rest assured that they are not going to specify longer intervals at the risk of higher warranty claims.

Oh, and one more thing regarding the "5 minute" dyno runs. That is the portion of the run after the initial warm up phase that puts the engine through it's paces. On a modern computer controlled engine dyno you can properly break in an engine in a matter of minutes. Again, more is not always better.

"I personally never bought into the 3000 mile change intervals. Those have been engrained on the population by the Jiffy Lubes of the world for the sole purpose of boosting their bottom line. No major engine manufacturer ever specified those intervals for normal driving conditions."

Actually, the 3K change with DINO oil was not a bad thing. DINO oil performance drops off VERY QUICKLY as it wears, SYN does not. The hard analysis that I have seen on DINO would support the 3-5K changes with DINO, not SYN of course.

"I think if you were to get access to the engineering data within Porsche you would find that even with the 15,000 oil change interval the oil's ability to protect the engine is well within spec. I wouldn't doubt if their data shows acceptable wear well past 20K intervals. Rest assured that they are not going to specify longer intervals at the risk of higher warranty claims."

I have never seen data (even from AMSOIL) that would support 15 to 20 K changes UNLESS the oil filter was changed at about 12,500 or so.

M1 is pretty much shot at 11-12K without an oil filter change.

I would be ASTONISHED if Porsche had hard data that showed that m1 could run 20 K without an oil filter change and be up to snuff.

In fact, M1 extended perf oil is only claimed to be good to 15K. AMSOIL will guarantee 25K IF you change the filter about half way.


"Oh, and one more thing regarding the "5 minute" dyno runs. That is the portion of the run after the initial warm up phase that puts the engine through it's paces. On a modern computer controlled engine dyno you can properly break in an engine in a matter of minutes. Again, more is not always better."

I would love to see some back up for this statement. Break in has to do with bearings, metal to metal, and ring seating. How does the computer speed up that process?

I do think the "bashing" you refer to is valid. If Porsche specifies 20K on the oil, it would have more credibility if it had many less failures to explain.

PS- I love Porsche but am not blind to their blindness on certain issues.

:cheers:

I think they mean a engine, out of the car, being dyno'd with a computer.

I have heard previously that the majority of any ill-fitting metal parts can be seated in a manner of mintues on a new engine. Not sure about 5 minutes but I read somewhere it happens pretty quick.

"I have heard previously that the majority of any ill-fitting metal parts can be seated in a manner of mintues on a new engine. Not sure about 5 minutes but I read somewhere it happens pretty quick."

This is an interesting angle of inquiry. I will play with Google and see if I can find more on the topic!

:cheers: