Oil Change = Engine Failure ???

[Adam]

Wouldn't it be in Porsche's best interest(and the oil companies) to lower the mileage between oil change intervals if the oil is toast by 10,000 miles? Also, since the flat 6 holds about double the oil of a standard passenger car engine, I would assume that would allow for longer intervals?

[Steve Tinker]

Adam - a large quantity of lubricant can be be worse off than a small quantity. Do you know what 9+ litres of oil looks like after 10,000 miles of short / slow trips in a Northern hemisphere climate !! The oil is not nice to see, smell, touch or be part of a very expensive piece of equipment like an engine. That amount of oil takes about 10 miles to fully come up to temperature and burn off the accumulated acids and water vapour, while your average car's oil is up to temp at less than 5 miles.
Not many people have mentioned it, but I feel the car feels quicker after an oil change.......

Originally Posted by Steve Tinker

Not many people have mentioned it, but I feel the car feels quicker after an oil change.......

Mine feels the fastest after a wash & wax!

[jmatta]

Steve, your point is very well taken. Those that drive their cars around town, on short trips and errands, should definately change their oil every 3-4k miles. As you pointed out, the oil never gets hot enough to burn off the crud. I avoid driving my car unless I know I will get it good and hot, but still change the oil no longer than 3k miles (once a year for me).

I've also added the LN oil filter adapter and magnetic drain plug to my car to catch the fine particles the standard filter misses. I'm really curious to see what the drain plug looks like next time I change oil; hope there aren't a bunch of filings attached!

[geoff]

Originally Posted by Adam

Wouldn't it be in Porsche's best interest(and the oil companies) to lower the mileage between oil change intervals if the oil is toast by 10,000 miles? Also, since the flat 6 holds about double the oil of a standard passenger car engine, I would assume that would allow for longer intervals?

I talked to a mechanic at the dealer shortly after I bought my '01 Boxster way back when it was still under warranty. He said the main driver for longer oil change intervals was government pressure on car manufacturer's to reduce the amount of oil that had to be disposed of. All the service writers at my dealer say the Porsche recommendations are fine, cars burn cleaner each model year, and actually turned my friend away several weeks ago and told him to wait another year before changing his oil because he didn't drive the car enough to justify the expense.

If you look at the Porsche recommended service interval today (see http://www.porsche.com/filestore.aspx/default.pdf?pool=usa&type=download&id=maintenanceintervalsforporschevehicles&lang=none&filetype=default ), Porsche has very quietly changed the oil change interval for my '01 Boxster from 15K miles originally down to every 12K miles. I have been changing the oil every 7,500 miles on both my Boxster and '05 Carrera (with Porsche saying every 20K miles for the '05 model year) and am thinking about following MarcW's example for over 200K miles and changing to an every-5K-mil oil change interval.

If you look at the Mobil1 web site, the "extended performance" Mobil1 oils say "Guaranteed performance and protection for up to 15,000 miles", and the 0W40 used in our cars aren't listed as extended performance. The Mobil1 FAQ just says "Mobil 1 with SuperSyn Technology exceeds the latest industry and OEM requirements. It is designed for vehicles under warranty and will provide protection for the maximum oil change interval recommended in your owner's manual or by your oil life sensor" Lots of disturbing ways to interpret that statement1