The following writeup explains why Porsche and other companies have cut down the oil change interval time. This is in response to the change in Zinc and phosphorus levels in oil, which help protect the engine.
This is interesting reading if you have not seen it before.
http://www.lnengineering.com/oil.html

 

I thought it was because the dealer wanted more foot traffic from the more frequent visits..

 

Leaving oil in an engine beyond 7,500 miles is crazy. Oils break down synthetic or natural.

When Porsche told me oil was good for 20K miles I thought they were nuts, and I still do.

I am changing synthetic oil in my 360 every 5K miles or 1 year whichever occurs first.

Oil is cheap. Damaged components are not.

Had a 733 BMW and sold it at 266K miles-didn't use or leak a drop of any fluid or undergo any major engine work except timing chains and one noisey rocker replacement.

I changed oil & filter every 3,500 miles.

Was worth every penny.

 

When and if Mobil 1 comes out w/ a 0-40w of thier new Extended Performance oil, Porsche and others may go for longer intervals (15,000 miles) as it contains 50% more of the good stuff (super-syn) than regular Mobil 1.

Have a look:

http://www.mobiloil.com/USA-English/...rformance.aspx

 

The shameful part of synthetic oils is not only their high cost but that they really offer no benefits over what good parafin based waxes such as Penzoil have always offered.

There are parafin based and sulfur based oils. The parafin based oils from Pennsylvania have always been superior.

What a shame we can't put those back into our synthetic oil engines!

 

1980's thinking.

 

agree-
vehicles run far more efficently now a day and oil and addatives have significantly improved. No longer are vehicle carborated (big toliets that dump fuel) into the oil. This was a big reason for the 3000 mile oil change as the inefficent combustion led to premature breakdown of the oils as well as their detergent packages. Cars run far more efficently now and IMO the 3k mile oil change is some B.S that oil companies want you to buy into. Porsche did cut the interval- sludging had become a problem (like p.o.s. audi's) and bumped the interval down. Now 20k seems extreme I agree, however their is no reason that a vehicle today couldn't go 7500- 10k on synthetic oil. Any less (IMO) is like dumping money down the toliet. While replacing the oil is cheaper than fixing broken components I agree- But if you are following MFG specs (and can prove it on your oil changes) the dealer cant say s#it if something happens.

 

OWM makes good points, but again oil is an inexpensive commodity.

I prefer to do it my way because I believe it's a easy step to long term engine life.

Why not do it?

 

Why not replace your tires every 3k miles? Its cheaper than repairs should you have a blow out from early tire failure.

 

my first oil change was at 3.000km......and I will change it every 10.000km!!!!
20.000 ARE YOU CRAZY?!?!?!

 

Ah, thank you very much (in an Elvis voice)!