pred8or

I had an early 2001 E46 M3. They were having a 1% engine failure for a while due to a main bearing failure which eventually got recalled and they extended the warranty. Prior to BMW stepping up to the plate I had my oil changed at 7500 mile intervals or half of the 15K suggested by BMW. I then sent a sample of this oil to an independent lab Blackstone Laboratories for analysis. I was amazed by the results. The oil was always within all specs measured and comments like this oil could have gone alot longer in this engine were common. I became a true believer in synthetic oil. Having said that I still believe cutting the manufature rec in half just good judgement. My Cayenne has been changed religiously every 10K is going in for its 9th change in a week or so and I have never added a drop in between. Lastly it seems the 997 uses alot of oil so by the time 10K rolls around you probably already changed it once?

Alstoy

Ok, I'm off to get the oil changed. Where's the dipstick?

InTheAir

Between the driver's seat and the steering wheel.

Edgy01

I get 5,333.17 miles!

sclemmons

I have 300,000 on two BMW's using Kendall GT1 20-50 and changing it every 3000 to 5000 miles. Synthetic is a new thing at my house. 7500 miles between changes is off the chart in my experience. Porsche may be right but a long interval just does not seem prudent to me.

Does everybody here use Mobil 1 or are there any other non-synthetic brands you favor?

Deanski

When I had the Lexus SC430, I changed both oil and filter at 5000 miles with Mobil-1.

When I took delivery of the Porsche, I dropped oil and filter at about a little over 5000 miles again Mobil-1. I changed both sooner actually as I wanted to clean the engine from any break-in lubes, sand casting debris, metal finings etc after breaking in the engine.

My view is oil and filter is cheap insurance, and since these have Variocam, the smaller holes for the lifters along with other engine parts can get a bit clogged.

Besides, these engines like to rev freely, so fresh oil and filter can only help. And, after seeing one of these engines torn down, sure looks nice when it clean and not looking coked up like some old engines from the past.

So, I'm a 5000 mile guy maybe a bit longer depending, but no way whould I leave oil and filter in a car for 20,000 miles. Unless we had to use Shell Helix oil which is big $$ per quart.

Deanski

OldGuy

1999 Porsche Great comment. I know guys on Rennlist whom buy what Porsche says Hook Line and sinker and then ridicules people for doing their own research and coming to a different conclusion than Porsche. You never know what a manufacturer has done or received to proclaim a certain oil as "THE"
fill Oil for its cars. Certainly no oil is the one fits all oil for all conditions.
again nice post.

sandwedge

Makes sense for BMW but not so much for our shops who ask anywhere between $300 and $800 for an oil change. If it was all about $$$ why aren't they recommending 3000 mile oil changes?

Mark1996

Does anyone here remember when Mobil One first arrived in the mid-seventies? Mobil in their ads claimed it only needed to be changed every 25k miles. This was when most vehicle manufacturers were requiring oil changes every 3k miles. As I recall, the manufacturers still required the 3k mile oil changes regardless of whether you used Mobil One or not. Of course, air filters and spark plugs along with points and condensers were changed every 12k miles. I remember reading classified ads for 911's in which sellers would claim that the engine oil had been changed every 1k miles. It looks like we have come a long way.

I have no reason to suspect that Porsche sets the 20k oil change interval or recommends Mobil One based on some improper motive. Wouldn't Porsche want their engines to be free of oil related failures?


Someone mentioned that for 2008, Porsche went back to a 15k oil change interval. Is this because of some real world issues noticed by Porsche?

Jlangmd

3.1415926

InTheAir

Pi to 1000 digits:

http://www.math.utah.edu/~pa/math/pi.html

MrBonus

Damnit!

MrBonus

That actually works out to about what I change my oil at.

I was right!

p-cardriver

I just can't resist this one...

1. A agree that other than cost there is no harm in changing more frequently than mfgr recommends. Cheap insurance.

2. I also know that its possible to run an engine for 5,000 or more hours between oil/filter changes in moderate duty, with a large sump (mainly for make-up as some oil gets consumed), synthetic oil and good filters. This is in power generation with variable loads, but constant operation, fueled by natural gas (no lubricating or cooling qualities in that fuel, compared with diesel or gasoline). The engine I'm referencing is a GM production engine of approx 7 liters. The oil analyzes amazingly clean at that interval, on multiple units in many climates. (break in oil always has junk in it, and I would never go past 2k miles without a break in oil and filter change). Now my PCM says I average 40 mph or so, but I think that is higher than most since I drive interstates a lot. But lets just use 30 mph to be conservative. 5000 hours times 30 mph is 150,000 miles between oil changes. So I really don't have any problem with 20,000 hours on a production engine, in theory. It ought to work, but I get anxious about it and prefer the peace of mind of more frequent changes. For my driving I would be comfortable around 10k mile intervals, maybe 15k if I had more Porsche experience (I'd do 20k on a BMW except an M which I'd do much sooner).

3. For more extreme duty, more frequent changes are appropriate. Lots of city stop-and-go driving, track use, etc.

I once met a guy with a 1930s Packard who had never changed the oil. He would replace the filter every few thousand miles and keep the oil topped up. This was pre-synthetic and he had well over 200k miles on the engine with no rebuilds. But one example is just an anecdote.

So I've gotten over the 1,000 and 2,500 and 3,000 mile oil changes of my youth, and I'm pretty comfortable at over 10k miles. YMMV!

p-cardriver

Bob in NY

Once a year or every 5k with German Pentosin 5W40 full synthetic. I can't see the downside of that schedule.