D.D.

Does the oil "degrade" in the engine over a year? Even if the oil has only 3500 miles on it in 12 mos.....is it necessary to change due to "what" factors?? Just a thoughtt??

99firehawk

no no degration, just the absobition of moisture from the air moisture+bare metal + no good


change you oil

boolala

Who recommends this? I've never heard this as a factory recommendation.

gravedgr

Recommended by whom? Porsche doesn't recommend that.

I have almost 6000 miles at 4 months, 8 days.

ChipAZ

Some believe that due to the close tolerances in a brand new engine that the mental filings that are shaved off will harm the engine. Shortening the life of the engine.

Also a lot of us are still getting used not changing the oil for 10 or 20000 miles with synthetic oil. It's hard to believe for those of us that want to do everything possible to give the best care to the car.

jerryrice

Given the price of the car, the price of the oil, and its easy to do yourself, why is there even a debate , just do it yourself, often, you cant hurt anything by changing it to much.

Mike Murphy

It's in the manual, but yes, the oil picks up many things, not just moisture. The reason for the once per year is because some people only run their cars 1,000 miles or year. That doesn't mean that the oil change can wait 15 years.

D.D.

Good Point!

OCBen

Recommended by me. How could Porsche possibly recommend that and not be in blatant contradiction to the owners manual?

Actually there are quite of few articles that I've come across that make that very recommendation, and at least one was posted here in this forum. But any mechanical engineer worth his salt will make the same recommendation.

It's a known and understood fact that rotary components of engines, though precisely machined, are nevertheless manufactured within acceptable plus or minus tolerances. During the wear-in process these components are worn down naturally until they find their true centers of rotation with respect to their mating components. Once they do, the efficiency goes up, horsepower goes up, and break-in is effectively over.

The wear-in process is effectively the final machining stage where parts are honed to perfection. Think about that for a minute. And the byproducts of this machining process are the fine metal particles that can be seen in the oil. I for one provided empirical proof of this.

Now, the question you must ask yourselves is do you want to continue driving your car, knowing these metallic particles are floating in your oil and coming between engine components, and wait until 20,000 miles for your first oil change to dump these metallic particles out?

Some of you may be quick to point out that it's the job of the filter to trap these harmful metallic particles and thus prevent them from harming the engine. Well, what if the filter in your car happened to be a defective one that slipped through quality control? It could happen. Are you willing to risk the life of your engine on the integrity of a paper filter? Do you feel lucky?

Ideally, an engine would run best in an open lubrication system. Fresh oil from an endless source would be pumped through the engine (after preheat of course) and dumped out along with the products of combustion and other debris. But to make an engine practical it must operate in a closed lubrication system. And so petroleum engineers have continuously improved oils so that they can last as long as they can before needing to be dumped out.

The "ideal" engine will run forever, as there will always be a layer of fresh oil between parts and no parts will ever come in contact with each other and no engine wear will result. The life of the practical engine is largely dependent on the quality of the oil - as any oil manufacturer will tell you.

Changing the oil frequently is thus beneficial to the engine. Changing it not often enough will cost you much more than the oil changes would have.

Mike Murphy

In some of my previous threads, I too, recommended changing the oil/filter frequently during the "break-in period," only to be told that Porsche engines are broken-in at the factory. It seems that no body has been able to document the break-in procedure at Porsche. If if they do put the engine on the dyno and run it up to redline, this is not a break-in procedure. This is just a test to see if it is going to break apart. They do this to cover their butts.

My guess is that Porsche and other large companies do not have the time to run miles on the engine to perform a proper breakin.

gpjli2

There are individual differences between engines. I changed M3 oil after "breakin", 1200 miles. It came out pristine with no visible debris and the same color it went in. My friend did his and the oil was grey and had just visible metallic particles throughout. Driving styles were similar.I have no idea why one engine runs in cleaner than another although you might assume it has to do with bearing tolerances, esp with the E46 engines. Whatever the reason, I do not understand the resistance to one "extra" oil change over the life of a car even if it may benefit some engines more than others.

OCBen

That makes perfect sense. Some components may be closer to nominal dimensions and some may be at the limits, hence more wear would be expected from them.

For those who may be wondering why Porsche just doesn't come right out and make this engine saving recommendation, well, hello, Porsche is in the business of selling cars and engines and parts, not in making them last forever so you can hold on to them and never buy another one. That's an exaggeration of course, but I think you can clearly see there is an inherent conflict of interest here.

The marketing folks there want to claim that the car has longer maintenance intervals than before - an improvement for the consumer! What I would like to know is what do the mechanical engineers of Porsche who purchase a 997 for themselves do (presumably through the employee discount plan). I'm willing to bet they change their oil early and often.

Mike Murphy

I see your point, but Porsche is also concerned about reliability. Or at least it used to be a top concern. Porsche will not benefit if engines start breaking down.

There must be something in the newer technology engines that allows them to run beyond 200,000 miles with these extended oil change intervals.

ChipAZ

Does anyone have any data on how long these engines last under the 20,000 mile maintenance program. I admit that I don't know how long this policy has been in effect.

OCBen

Of course, that's why I said that statement was an exaggeration. And it's a simplification too.

Yes, you would think they'd be most interested in reliability, as this is really what consumers want most of all. They also know consumers want as much maintenance free operation as possible. So there's an obvious conflict of interest right there.

Maybe they projected that the life of their engines, under their recommendations, would be close to 200k miles. And many consumers would be happy with that. But as most of you realize, the life of an engine can be charted on a life curve where performance and efficiency reach their peak sometime after break-in, hold that level for some time, and then slowly but surely start to decline over time until the engine is effectively powerless and for all practical purposes dead. Maybe Porsche considers it a success if an engine dies at 200k miles, assuming this to be their projected engine life. If so, it's already losing power at 150k miles.

Those of us who change the oil often are only making sure that the power levels stay on top for as long as possible, that's all.