gregroselli

It was worth a shot. Are there any signs that I am burning oil other than just low oil w/ no spots in the garage?

cdodkin

You may see blue smoke at start-up, and/or at high revs

Also excessive black soot in one or both tailpipes may be a sign

How much are you using?

1999Porsche911

Actually, heated debates such as this are some of the best threads. It may help, otherwsie brain dead people stop and and think and maybe realize that they shoud not necessarily follow the hurd just because an icon, such as Porsche says they should. Maybe some of them will do a little research on their own and base their decision on what is best for them and the way they drive.

I just roll over laughing everytime I see the agrument "use the oil that Porsche recommends becuase they know what is best for your car", yet those same people, somehow determined that the Porsche engineers were wrong about things like, tires, brakes, intake systems, etc.

wrljet

It can only go three places:

- on the floor (unlikely it leaks enough underway to show up on the dipstick but never drips on the floor)
- out the exhaust pipe
- into the coolant

All engines use up -some- oil. Otherwise the rings and valve guides wouldn't be lubricated enough and fail in short order.

BruceP

Sorry, flawed logic in your rhetoric, there. I think that it's reasonable to trust them on oil because the objectives for oil selection are simple and broadly in common between Porsche and the people who drive their cars. There is no "right" when it comes to things like tires, brakes, intake systems etc. When I choose those things, I don't have to abide by their cost accounting or their consumer research or their environmental and noise regulations or their production efficiencies or their product liability exposure or the exigencies of four season usage of public roads on several continents or variability in fuel quality or whatever. Those things you mentioned are all compromises made to reconcile conflicting agendas to appeal to the largest possible number of consumers. Oil, it seems to me, isn't such a fraught question.

cdodkin

Bruce - most of the compromises you mentioned could equally apply to oil selection by the manufacturer.

They are under the gun for emissions, environmental impact from used oil, Govt compliance regs, protection from possible litigation...

And then there's the $$$ associated with an oil being 'recommended' by the manufacturer.

It's not just about the engineering I'm afraid.... You have to look at the bigger picture when Govt and big business are involved.

wrljet

There's also the cost of warranty repairs caused by recommending the *wrong* oil.

BruceP

Sorry, not buying. Yes, those things also apply to oil. But my argument is over the question of degree. There just isn't the range of "right" with oil. And when it comes to government and big business - two things I've got more experience with than I care to admit - there's always a motive. It would profit nobody for Porsche to promote an oil for their cars that was destructive. Not Porsche, not the oil company, not any government. Without a motive (and in the absence of rank stupidity) there is very likely no crime.

I mean, seriously, the very fact that this is such a debate is reason enough to doubt the advice of one or another anonymous guy on the internet. With that much controversy, I'm going to put my money on the people with the most to lose by being wrong: Porsche.

The fact that I have on my desk right now an oil analysis for my '00 strengthens my conviction: The car's previous owners were the "one oil change a year = all the maintenance you need" types, and it has 80,000km on it. It's been run exclusively on Mobil 1. "All component wear is within normal parameters", according to the report. The worst you can say about the car is that it's had the RMS replaced, but I don't freak out about seals like some folks do. Bottom line is, the car runs like a champ and has a healthy motor despite some neglect (by my standards), so I'm going to proceed on the assumption that the oil is working just fine. What on earth would be my motive for taking a chance?

cdodkin

Back to Bruce's point - for example:

Have you ever heard of CAFE?

(Corporate Average Fuel Economy) reported to the Federal Government.

CAFE is the combined average fuel economy of all of a vehicle manufacturer's product line.

Minimum CAFE levels are specified by the Federal Government.

In order for a vehicle manufacturer to continue selling profitable large vehicles like SUV's, i.e. the Cayenne, which typically have poor fuel mileage, and still meet mandated CAFE requirements, they must also sell smaller cars which have much better fuel economy ratings to offset the poor fuel economy ratings of the larger vehicles.

Sometimes, that's not enough.

So, a change to say 0w40 oil will allow a vehicle manufacturer's overall CAFE to decrease by a very small amount, typically in the tenths of a mile per gallon range.

0w40 oil is a lighter viscosity than a 5w50 oil and therefore has less internal engine frictional losses, or less drag on the crankshaft, pistons and valve-train.

This decrease in frictional power loss promotes increased fuel economy. But, the minimal increase fuel economy is virtually undetectable to the average consumer without the use of specialized engine monitoring and testing equipment when compared to say a 5w50, 10w30 or a 0w30 viscosity motor oil.

So, the 0w40 offers you a fuel economy increase that you'll never notice, but will enable the manufacturer to meet Federal CAFE requirements.

But what about engine protection?

What if your 0w40 oil has less film and shear strength than say a 5w50, 10w30 or a 0w30 motor oil?

Check the specs for yourself - look for HT/HS ratings...

This could lead to increased engine wear under today's demanding heat and high-stress engine performance conditions.

Of course, since vehicle manufacturers know that most consumers don't expect to keep their vehicle longer than 100,000 miles or so, that's ok.

You'll receive adequate protection in order to keep your engine running for 100,000 miles. But, beyond that may be another story......

So the engineering may be overruled by regulations and big business - you need to do your research people!

BruceP

Um, sorry, no. Porsche generally does not in fact meet its CAFE targets, and pays penalties for this. So, while I can't say with certainty that you are wrong (any more than you can say with certainty that you're right), the government record suggests they would rather pay financial penalties than make bad engineering decisions. For example, in 2004 they paid $4,357,782 in fines for failure to comply (Source: NHTSA, public record) Next?

cdodkin

You don't think that any reasonable business would want to reduce their penalty payments if they could do so?

The penalty for failing to meet CAFE standards are rated per tenth of a mile per gallon for each tenth under the target value times the total volume of those vehicles manufactured for a given model year.

Even a small change in CAFE for Porsche, could significantly reduce their payments, or equally allow them to introduce an SUV without increasing their penalty payments.

We're talking millions of $$ off the bottom line just for PCNA.

And remember, CAFE is just one set of Govt regulations that we're using as an example.

wrljet

Most of the high-end German makers don't meet CAFE, and they don't care.
The fines are hundreds of millions of $$$, but it's just a line item on their balance sheet.

Bill

BruceP

Man, you're not kidding. In the same year that I quoted for Porsche's fines, BMW paid more than $14 million.

I don't mean to be rude, but I'm just not buying all this Oliver Stone stuff.

1999Porsche911

CAFE penalty is not all or none. They are caluclated after determining by how much below the standard you are. Therefore, increasing fuel economy, even though you are below the standard, saves the car manufacturer money.

NEXT?

(isn't this fun, finding flaws in other people's logic?)

wrljet

They don't care. Period. It's all in the price you pay at the dealer.