oil

Just bought an '04 cab (couldn't wait for the 997s; also, I don't think it's a great idea to buy in the first production year of a new series-- there are often a few "kinks" to be worked out). Anyway, my queston is how often do you guys change your oil? (miles and time passed). Thanks.

Me 5000 or 1 year, book 15000 or 1 year.

i change mine every 8-10K miles, which i always drive in less than a year. mobil one has a 25K mile lifetime, but the car manufacturers won't allow mobil to publish that fact because it could cause warranty problems. my brother is responsible for everything related to lubricants for the largest elevator/escalator company in the world, so he has a line direct to the scientists who develop lubricants at the major oil companies. he found out about the 25K mile lifetime of mobil one from the scientists at mobil who actually developed it. 25K miles is where the detergents in the oil wear out. in conventional oils, they totally wear out at about 5K miles, but it really depends on the specific oil. so you could actuallly run mobil one in your car for 25K miles safely, but their oil filters wear out at 10K miles. in a p-car that's driven hard (as they all should be! ), i don't know if the 25K limit is true or not. obviously 15K is ok though since that's what the factory recommends. one thing i have to admit a lack of knowledge about is the 996 oil filters. from what i've read, they use a replaceable filter element? can you use a standard mobil one oil filter?

I was suspicious of the car manufacturers when they pushed out the oil service intervals since many of them pay for routine maintenance for a period of time. This obviously doesn't apply to Porsche. This is nice information about the new synthetics. I wonder if the oil's life span is degraded by autocross, track, or stop and go driving. I still have a hard time waiting for 1 year or 15,000 miles to change my oil. I have a much harder time knowing that the oil filter is changed every other oil change. I'm going to change my oil/oil filter every 5,000 miles and maybe sooner if I get enough track and autocross time. Old habits are hard to break. OBTW my oil seems to be holding up after the 2,000 mile break-in and one autocross.

7,500 or every 2.5-3 mos. they usually coincide about the same time. my car burns zero oil and now registers 64k miles on the clock.

okay... mobil 1 has a 25,000 mile lifetime... but how long can you leave it in the car... say someone that puts maybe 8-9000 miles/year on it... I guess what I'm asking is regarding the lifetime... is their a time limit to the oil as well as a mileage limit? cheers Pete

Very helpful, thanks guys.

Major variables in the life-of-oil formula are the amount and degree of heat it is subjected to, and temp cycling that induces condensation in the oil. The latter is why Porsche says change it once a year regardless of mileage. The 15,000 mile drain interval is for driving under normal conditions, and is set conservativly for obvious reasons. Use your judgement within these guidelines.

as gretch said, oil should be changed yearly regardless of mileage because of the water that gets into it over time. that's not to say it's definitely going to harm your engine (or actually the water in it) if you leave it in there for over a year. it MIGHT, but there's so many variables in it that the one year rule is generally a good one to follow!