When To Change Oil

[Brucelee]

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.

[deliriousga]

Sorry, I don't know that one.

[donv]

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.

[Brucelee]

Conventional DINO oil IS shot at 3K.

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

Seems to work fine.

Originally Posted by donv

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.

[MNBoxster]

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

[Brucelee]

Jim 99 is dead on with his post.

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

[Brucelee]

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

Originally Posted by bmussatti

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.