Regular oil vs. synthetic

Had to put a quart of regular 10W-40 in my car in a pinch (was all that was available) to get it to the dealer to patch an oil leak. The original oil was Mobil sythetic. Is this a real concern or can i just ride it out till my next oil change in a few thousand miles?

you're fine

I regularly add 1 quart of dyno oil to all my cars and boats. Better for the seals.

You guys are so fast its scary. Thanks. This site is excellent for new owners.

What weight of dyno oil do you add to your 15W-50 synthetic?

Tim stop it! I was almost afraid to open up this thread in fear of what I might find and here you are stirring things up again!

Whatever I have hanging around. Typically a 10W-40 since I use that in one of my boats and it's on hand. 5W30 in my lower compression, family cars.

Oil did I hear oil!

OK Guys, you heard it here first, 1999Porsche911 stated that he uses 10W-40 in his P-car! While it may not be "Mobile Water" as he calls Mobile 10W-40 synthetic, it is a start! I guess he is a closet 10W-40 user!

For the record, Mobil Water is 0W40 and that weight is the ONLY weight oil I have strongly recommended never to be used. I have always suggested 5W40 and higher, with 15W50 being my preference for a 996. My arguement has been more against Mobil Wtaer than for another oil. For the average 996 driver which involves starting the car, driving like and old lady for an hour, placing the transmission in neutral at al stop lights, and then speeding home at 40 mph and washing and waxing it. adding a little oil to the crankcase and then parking it back in the garage, 5W40 is fines. For those who push their cars, go with 5W50 or 15W50. I have never stated that 10W40 shoiuld not be used.

What's wrong with 0w-40 if you say 5w-40 is fine? Won't 0-40 and 5-40 act similarly when hot and the only difference being that 0-40 flows better when cold? I've read of one instance where using 15-50 wouldn't let the lifters pressurize.

Speaking of oil, I think I'm going to order this... http://www.deandeluca.com/cgi-bin/nc...?cgrfnbr=11377 I'm over the at the moment.

Actually, it is the opposite. Lifters have more problems at startup with 0W40 that with a 15W50. Preference is to go with the 50 weight oil. Mobil 1 in general and Mobil 0W40 specifically, have a history of not protecting seals and leaking internally (burning). The 5W40 has less of burning problem, and the 15W50W all but eliminates it. If I HAD to run 0W40, I would definately add 2 quarts of dyno to aid in seal conditioning. The push for a low viscosity oil is only to meet emmision requirements, similar in reason why you now only change oil every 20,000 miles. It it not because it is best for the engine, but it is best for the tree huggers. As I stated earlier, a 5W40 is fine for a show car, but not for a high compression car that is aggressively driven if longevity is your goal.

1999, You are one of the few technical gurus on this site, I am due for an oil change soon, so you think I should go with 15-50 synthetic? and not to sound dumb (maybe too late ) but what do you mean by adding "dyno" to your 0-40? TIA

I saw Mobil 1 0W20 at the store yesterday. Amazing. What number is used for viscosities thinner than 0? Bill

One of the drawbacks of a purely synthetic oil is the inability to maintain the flexability of various seals in the engine. Although additives have been improved over the years. they still have not found a combination of seal material and additive that will work. A dyno oil (regular mineral motor oil) helps to keep the seals properly conditioned and flexable. This is why, 9 out of 10 times, filling your crankcase with dyno oil when you have a small seal leak, will completely eliminate the leak, as it restores the seal, making it flexable and reversing the shrinkage. My recommendation would be to use the 15W50 in Connecticut in the off winter months. The Mobil 15W50 Extended Performance still has the correct level of cleaners. Many of the other grades have reduced them. Elf is also a great oil as is Castrol Syntec and many others. If you are currently running 0W40 and burning oil, in many cases you'll see an immediate reduction in oil usage as well as smoother idle and quicker engine response using the 15W50. With 0W40 oil, your hot engine is unable to maintain adequate oil pressure (as your gauge will tell you) to maintain safe clearances between and crank and IMS bearings. Using 15W50, pressure is no longer a problem. There are many sides to the oil deabte and it boils down to what you decide based on looking at all sides of the debate. Many people just accept what Porsche suggests, but many of those are also the ones that accept that it is normal and good for the engine to burn a quart of oil every 500 miles and that it is normal not to be able to shift into 1st gear easily, that there is no need to change your motor oil more frequently than every 20,000 miles, etc, etc. I think they refer to these problems as the "character" of a Porsche. I call it "denial". Common sense would dictate that if someone is burning oil using a specific brand or weight of oil, they would try an alternative?

Virgin Olive Oil.

The oldest Porsche approved oil list I have is dated March 17, 2000. There is a convernional mineral oil on the list. Exxon Superflow 15W-40. And, oh my god, Mobil 1 15W-50 synthetic is also on the list. Extra virgin olive oil. Nothing but the best for my Boxstir.

I read that the Ferrari owners use the same Olive Oil but add a little red vinigar to it.

I use 15w-40 as 1999 susggested on my 2000 SC, I like the extra oil pressure it gives.

Use any oil on THIS list. Adding non-synthetic won't hurt you but it also won't do anything, especially for your crankcase seal.

Wrong! This has been proven over and over and over again. Seals remain more flexable and do not shrink and dry out as much with dyno oil. Can't argue against fact. Some synthetics use more seal conditioners than others. Since so many of you always refer to web pages as FACT, here is one for you. http://www.auto-rx.com/pages/faqs_old.html#U13 There are dozens and dozens of other that also state that non synthetic oil helps return the plyability of seals. What do you think the main ingredient in seal conditioner is?

It's in the Panerama archives if you look through there, it was cool out (IIRC around 50F or so) and the lifters wouldn't pressurise because the oil was too thick to even get to them.

Current no conventional oils are recommended by the TSBs.

What material is the main crankcase seal made from? And what material is impervious to the seal swelling conditioners/additives/agents that you were telling people would help prevent RMS leaks, if only they poured in a bottle with each oil change? What year did Porsche start using synthetic oils? Do you really think the german engineers @ PAG chose the gasket and sealing materials used in the M96 without understanding the effects that the synthetic oils (that they were specifying) would have on them?

I don't know much about this stuff, but I have to agree with the logic of this point. I just can't buy into any advice on a message board that's based on the assumption that a) Porsche are idiots, or b) Porsche is engaged in a fiendish conspiracy, the motives for which are too arcane for mere mortals to understand.

If you want to fight about oil then here is the forum for you http://www.bobistheoilguy.com/

Hi, IMHO the misinformation on lubricants and lubrication that has been Posted by 1999Porsche911 over several threads and several months needs to be carefully analysed before acting upon it. Most of his information can be quickly dismissed by the supporting facts. He never seems to be able to supply any to support his own theories! Two follow; 1 - "Actually, it is the opposite. Lifters have more problems at startup with 0W40 that with a 15W50" And, 2 - "With 0W40 oil, your hot engine is unable to maintain adequate oil pressure (as your gauge will tell you) to maintain safe clearances between and crank and IMS bearings" Sadly he has a very limited understanding of fluid dynamics and lubricants/lubrication in general! And many others have pointed this out to him! I suggest anybody tempted to believe his Posts should at the very least consult an Oil Company's Lubricants Engineer or their Chemist first. Sales people won't do. Many very competent people here on Rennlist and elsewhere have called his bluff before!!! A much simpler way of course is to believe what the Porsche Factory's engine Designers and Engineers have to say. Following their Technical Service Bulletins (TSBs) on lubricants (which always supercede Handbook data) and are produced in the light of field performance of the engines in service is the best advice you can get For those persons not already aware of it, Porsche first filled with synthetics in MY1992 - an SAE30 viscosity (10w-30) at first and then with a SAE40 viscosity (5w-40). Both were Shell lubricants Porsche's MY98 TSB Approvals List for 996 Carrera and Carrera 4 engines Listed 241 lubricants from 109 Oil Companies or Blenders with technical details as follows; 1 - NO lubricants had a 15w cold start rating. All were rated at either 0w, 5w or 10w and most were 5w 2 - NO mineral lubricants were on the TSB 3 - The following viscosity lubricants were Approval Listed SAE30 0w-30 - 4 5w-30 - 8 No SAE30 oils are currently Approved by Porsche (exception V6 Cayenne) due to their lower HTHS viscosity. Porsche's minimum HTHS viscosity is 3.5cSt SAE40 0w-40 - 17 5w-40 - 108 10w-40 - 64 Generally the 10w-40 range of SAE40 viscosity lubricants was largely "semi-synthetic" and these have been superceded by 0w and 5w SAE40 lubricants. All 10w-40 lubricants Listed by Porsche in the TSB were semi or fully synthetic SAE50 5w-50 - 12 (Castrol 3, Eurol 1, Idemitsu 1, Meguin 1, Mobil 1, Mol 1, Motorex 1, Pentosin 1, Soprograsa 1, Tetrosyl 1) 10w-50 - 5 (Jomo 1, Kuwait petroleum 1, TotalFina 3) Most SAE50 lubricants Listed were fully synthetic with only 1 being a semi-synthetic Many "unknown" Brands were probably re-badged Castrol or Mobil lubricants Since 1999 only one SAE50 oil has been Approved by Porsche and that is M1 5w-50 SAE60 10w-60 - 2 - Both are Castrol fully synthetic lubricants No SAE60 viscosity lubricants have been Approved by Porsche since 1999. Many use this wonderful Castrol product in long distance racing. It has a history dating back to the mid 1970s and I had a hand in its development The TSB noted above is long outdated and has been superceded at least five times since These links may add to more understanding about engine lubricants https://rennlist.com/forums/993-forum/342882-oil-again-mobil-1-15w-50-new-formulation.html https://rennlist.com/forums/911-forum/341405-oil-question.html I do not work for any Oil Company and I am retired! Regards

Yea, Porsche is an expert in oils and seals. How often have they changed their list of appoved oils? What generation of seal are they on? When are you guys going to learn that if your car is burning a quart of oil every 600 miles or leaking from the seals, that maybe you should stop listening to Porsche and try something else. So many of you brag about increasing the hp of your car by adding one mod or another, yet shrug your shoulders about your biggest power thief.....burning oil. Maybe the question you should ask is ....what did Porsche change which led to the increase in leakage of seals? Is it a coincidence? I think not. There is even an article in Total 911 magazine stating "it is well known that Mobil 1 will leak where conventional oil will not" I guess it is not as well know as the author thought...at least to some on this board. And your question: Do you really think the german engineers @ PAG chose the gasket and sealing materials used in the M96 without understanding the effects that the synthetic oils (that they were specifying) would have on them? Exactly! Am I suggesting you run conventional oil in your car? Not at all. However, if you are leaking and/or burning oil, you should move away from Mobil 0W40 to a higher viscosity and use a mineral oil additive to the crankcase periodically if neccessary.

As usual, your blowing smoke again. I'll just pick out one WRONG statement you made: "Since 1999 only one SAE50 oil has been Approved by Porsche and that is M1 5w-50". You should read the owner's manual which clearly states 15W50. The car also came factory filled with Mobil 15W50. Sorry I caught you but I won't bother picking apart the rest of your incorrect logic. There are many intteligent people on this board and I think they can figure it out themselves. The one about the hydraulic lifters is hillarious!! Its obvious you got your knowledge of hydraulic lifters from reading forums like this rather than hands on experience. If you're going to attack someone, you should get your facts straight.

The thing I find ridiculous about the RMS problems is that Chevy V-8s used a piece of cotton clothesline rope for their rear main seals for years and they didn't leak or need replacing more often than the oil they held back. I use Mobil 1 in minivans and other motors and don't have seal leaks. Porsche has a decades-long history of taking decades to correct engineering mistakes. The 911 chain tensioners are an example. Plenty of other car companies managed to tension chains reliably without fanfare. Bill

First, all engines burn some oil, there's a very detailed GM TSB you can look for if you care to. Yes burning a significant amount of oil does waste some power, but I know my parents Porsche doesn't burn a significant amount of 0-40. Second, thicker oil than necessary wastes hp too. Third, this is a direct quotation from the PCA website "The 15-50 is just too darn thick, and the hydraulic lifters won't pressurize when the engine is started & run cold. In many cases, the engines will be down on power, will be low on compression, and will usually make significant if not alarming ticking noises." Here's another one "There is a strong possibility here that if you used Mobil1 15-50, that can cause the hydraulic lifters to fail to pressurize. That in turn will cause the engine to fail to achieve compression, and it will be difficult to start and won't run well until it finally warms up. That is why that weight of Mobil1 is no longer approved by Porsche (for anything but race cars without hydraulic lifters)." I really don't know where you get that hydraulic lifters prefer thicker oil. You say you have hands on experience, but this leads me to doubt you've ever torn down an engine.

You can find quotes (just look in the owner's manual for the early 996's) directly from Porsche that 15W50 is fine for hydraulic lifters. So why did they say it was fine then and not now? Why did they deliver many of the 996's with 15W50? Were they delivering a car with an engine that didn't pressurize the lifters? Wow, I can't believe the Porsche engineers screwed up! And to think..they are the experts. Stop reading and start doing and you''ll learn what is correct and what is marketting. Take a look at the timing variance on a 996 using 0W40 versus 15W50. It doesn't lie. Hydraulic lifter have been in cars long before synthetic oils came to market, let alone multi-viscosity oils.

1999, you are very,very wrong as usual. The amount of mis-information you spout about lubricants could fill a book! I'll say what Doug and others may be too polite to say: Quit giving people blatantly bad information that could damage their expensive engines. You need to lay off the oil advice. You are in way over your head on this particular subject. Stick to what you know instead.

It's been really entertaining to read some people are justifying at length, laced w/ tenacity why they're not using the oil that the factory a.k.a. Porsche engineers are advising that we owners use on our 996 911s. It's comical and better yet it's all free to read. I just changed the oil with M1 oh dub forty. How do you like them apples?

Porsche does not advise, recommend or otherwise suggest that you use 0W40. It is simply 1 of many brands and grades of oils that are on their SUBSCRIBED approved list. You can just as easily state that Mobil 5W50 is the oil that Porsche wants you to use since that is also on the list. People only read what they want.

OOPS! You are right, 0W-40 is what you call "mobile water." I was not trying to make it sound like you had never recommended 10W-40. My mistake on the oil weight! BTW - My post was TOTALLY in jest! It was intended to be a little satire on the great oil debate.

Isn't it currently the factory fill?

Yes, and the financial encouragement given Porsche by Exxon does not play any role in that decision. You can look at the different engine manufacturers around the world and easily identify who gets the most financial incentive from which oil company. IF in fact Mobil 0W40 was the best oil available, then it would be a no brainer for all engine manufacturers to use it. However, many must think that Pennzoil and Castrol and Shell are better than Mobil since they fill their engines with them. Just like the tires that come with a car, oil manufacturers provide incentive to the the car companies to get their products used. This, by itself does not mean the products are bad, but it is a large part of the decision process. And, do not forget the emission requirements these companies must meet, including gas mileage, A thinner oil may not be the optimum oil to use, but it gets their MPG's up. Changing your oil every 20,000 miles may not be the best for your engine, but this recommendation puts them in compliance. Keeping the same coolant in your engine for the life of the car may not the best for your engine, but, again, the car company must comply with emission requirements. The point is, you would be niave to belive that a car manufacturer does not make decisions that compromise quality and longevity in order to meet government standards.

For those that have the time, or just want some info on oil, suggest you download the following doc: http://www.trustmymechanic.com/motor-oil-bible.pdf It's a long read, but it's a whole load of motor oil info in one place.

As far as extended oil change intervals....Europe has been using synthetics for decades and the OCI's (oil change intervals) have been 10,000 plus for many years. If you doubt the capability there are plent of used oil analysis tests avaible for viewing at bobistheoilguy.com....many are Porsches using Mobil 1,Motul,Redline,etc....10-15,000 miles is not a long OCI...it's just that we are used to 3000 miles...10,000 miles or 2 years for an OCI is pretty darn reasonable for most of us if using a high quality synthetic. It is your money and your decsion of course, and if it makes you feel better,then that's great too!

Yeah, but if your change your oil every 10,000 miles, you are disgarding Porsche's current recommendation of every 20,000 miles. How can you do that. Are you saying that you know more than Porsche engineers? If you follow their recommendation for one thing because they are the experts, I have to assume that you would follow them for ALL recommendations otherwise the "expert" arguement does not hold any water.

On a side-note (seeing as how all the oil experts are in one place in this thread), if my 996 were burning oil as opposed to leaking it, could that make the fuel appear too lean/rich to the O2 sensors enough to trigger my CEL? Just trying to think outside the box here....

Most likely not. Your computer would adjust for the condition. Over time, the 02 sensors may get coked up sooner, but until then, they will adjust.

From now on, the use of the word "oil" is

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?

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?

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.

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.

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.

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.

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

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?

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!

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?

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.

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

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.

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?)

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

Yup, afraid you're right. Our friend is a bit vague on the business model of a company like Porsche. If we were talking about a high volume manufacturer, this kind of stuff would make some sense. A few dollars a car in exchange for some remote liability risk. But seriously, look at the unit margins on these things. No sane marketer would nickel and dime like that with his brand's reputation at stake when all he has to do is charge a bit more for the embroidered headrest logo.

Which is limited by market conditions - so if you can cut your base costs, say by shaving your CAFE and reducing a Federal fine off your bottom line by millions of $$$, then as a business, that's exactly what you'd do. Sound reasonable? You appear to be in denial that Porsche are in this to make maximum profit. Maximizing profit works at all levels - including oil selection by the manufacturer. It's business - pure and simple.

I hope they still have enough pride and honesty, though, to not recommend oils known to be inferior by themselves, just to make a buck. Hell, they're already the most profitable car maker by unit on the planet.

Sorry, but are you actually in business? Because I am, and the logic of this eludes me. This is a low volume, high margin enterprise. You don't survive in one of those by betting big on tiny marginal cost savings. A business that survives isn't trying to maximize profit, it's trying to maximize profit sustainably. I could see GM doing this. I could see Toyota doing this. But Porsche would have to have slept through four years of B school to make a dumb bet like that. It just doesn't make sense. Especially when, as you quite rightly point out, they could recover the cost from the oil company who put their sticker under the hood instead. Now if I was Porsche, I might try to improve my CAFE by, say, buying Volkswagen... hmmmm....

Some people have apparently no business sense. Bottom line is that all succesful buinesses worry about the nickle and dimes and anyone that would suggest that they don't would not be with the company long.

Bruce, I only run an IT company, so I bow to your experience as CEO of a major auto manufacturer

And as a matter of interest - I noticed that my Volkswagen TSB on oils (2004) now shows a change to Mobil1 0W40 in my Passat Wagon, where previously it was Mobil1 5W30.... And all since they introduced the Cayenne, I mean Touareg Just co-incidence I'm sure

Now, now girls. No need to get shirty. I have 27 years of marketing experience, advising tier one packaged goods, services and durables companies, including Toyota and Honda. Despite that, I'm not saying that I'm infallible. I'm just saying that my own understanding of how to run a big business doesn't seem to support the motives you speculate Porsche to have regarding the selection of oil grades. And Mr. 1999Porsche911 is, in my own humble experience, grossly overgeneralizing. I've been in countless meetings where profit has been foregone because short term wins would harm long term sustainability and value. Sadly, not everybody gets this, of course. I recommend a book called The Reckoning, by the late David Halberstam. It tells the tale of how Detroit gave away market domination by thinking just the way you are, so I'm not saying that you won't find people who agree with the 'squeeze every nickel you can' approach to business. You just won't find them in high margin businesses.

Many of the oils (including various grades of Mobil 1) have been reformulated recently, because of a lawsuit that allowed blends and oils using non-sythetic base stocks to be called true synthetics. Also a switch to a new API standard has removed some zinc and other additives (for EPA) that are important to various motors. The air-cooled guys are all in a twitter over this. And I suppose since we have flat tappet motors we should give it some consideration. Luckily Porsche, VW, and BMW continue to test oils religiously and update those recommendation lists for us! Bill

Bruce, I'm sure you have something more than intuition or personal business acumen to back your position that the move to 0W40 by Porsche was made solely based on on-going technical and engineering reviews, and was not influenced in any way by any external or internal financial considerations or legislation? I'm not telling you what to put in your car - I'm just asking you to be reasonable and look at the whole picture. There's more to all of this than pure engineering - it's engineering at a price point.

Bill - well aware of that legal action - Castrol did none of us any favors by pushing to allow PAO base stocks to be used to make synthetic ! Doesn't explain the move to 0W40 in this case, as 5W30 Mobil1 was already fully synthetic (by the pre Castrol definition). VW changed grades of synthetic in this case, so it's not a case of semi-syn to synthetic. Their move to all synthetic is easy to understand, after they had significant sludge issues in engines running on dino oil - and paid dearly in court for it!

I'm not really arguing with that. I'm grown up enough to know that it's also a business decision, not just an engineering decision. What I am arguing with is the premise that because it's a good business decision, it's per force a bad engineering decision. They have no motive to harm their own product. A good business decision would be one that returns something to the bottom line without creating new costs or liability. So, as a consumer, I'm then faced with my own choice: trust that Porsche isn't looking to **** me off and wreck my car, or assume that they're ruthlessly profit motivated and don't care, and cast my fate to some self-styled experts on the internet (who may be correct and brilliant, but also may not). So, as I said earlier, I'm going to bet on the people who have the most to lose by being wrong. And thank my lucky stars that I live such a good life that I can afford to spend an afternoon debating oil viscosity. I don't know where that is on Maslow's hierarchy exactly, but I bet it's right up there.

The cost of replacing all the blown/damaged motors (and loss of confidence and goodwill) is factored in too.

Try sitting on the Board of a couple of Fortune 500 companies and you'll see quite clearly how important spending and cost cutting is as well as how even the smallest of items are considered. Even more important if you are publicly traded.

There's more to it than the synthetic or not aspect. This website explains a lot of it. I have no idea if it's fact resulting from thorough scientific research and understanding, or a load of bull: http://www.lnengineering.com/oil.html

As stated before - if the new oil grade still gets your engine past 100,000 miles, do you think they give a damn after that? It's not as if they change the oil grade, and engines start seizing up at 50,000 miles. Be reasonable! It's a calculated position - a trade-off of engineering and economics. 99.9% of 996 owners could care less, because they would never expect to keep a car past 100,000 So that might seem like a reasonable place to make a compromise....

You're right: TSB's, Recalls, those are all nonsense too since they weren't what was done originally. And I never said you need to use synthetic oil for hydraulic lifters, I said they prefer thinner weight oil when cold. You keep saying "start doing" - have you ever torn down an engine? Saying that hydraulic lifters work better with thick oil leads me to believe you haven't. Also, you said that if 0-40 were the best all cars would use it. Again leading to me you have never torn down an engine...I'm also lead to believe you don't know what clearances are.

Which boards do you sit on? Sorry, but this is simplistic and naive. Of course corporations are concerned with costs. But Toyota, for example, doesn't go looking for the cheapest supplier of steering wheels. They look for the cheapest supplier of steering wheels that MEET THEIR SPECIFICATIONS. Costs are not managed ***** nilly to find every penny, they're managed to serve a strategy. If cost control was all Porsche cared about, do you think they'd still be building most of their products in Germany? Do you think they'd bother with an engine design that is absolutely useless for anything other than one chassis? My own business has a nine figure top line, and industry data shows that it's at the top of the profitability heap among its peers in my market. I scrimp on copier paper and paper towels. I don't scrimp on computers or syndicated research subscriptions. I know what's strategic and what is not, and I'm inclined to think that maybe Porsche does too.

Seems like a funny decision for a company that brags about the fact that 70% of the cars it's ever built are still on the road. Anyway, look, I'm going to tap out, here. All this stuff is paranoid speculation, whereas the scant facts on the table seem to support letting the car company do its job. Life's too short to go looking for bogey men. If you can show us a worn out 996 engine, then this conversation will get a lot more interesting. In the meantime, I just thought I'd toss in another perspective, one that was, to use your word, "reasonable".

Bruce, I know as much about your business model, as you do about mine. And we all know F-all about how Porsche is run. So you can believe what ever you like about their business model, their triumph of engineering over costs - it doesn't make it so. To deny that economics have any part to play in the oil decision seems foolish. So once you accept that point - you have to concede that the choice of oil in the car is no longer a pure engineering decision.

Land Rover make the same claim - doesn't stop my Discovery from marking it's territory everywhere it goes with copious amounts of Mobil1!

Don't take me out of context, friend. My reference to the 70% number had to do with your 'who cares if it self-destructs after 100,000 miles?' point. My Disco has made the odd spot on the rug, too. But you know what? It will still be going strong at 200,000 miles. Leaks aren't the end of the world. If it's any comfort, though, they fight about this over on discoweb.org, too. And my position is the same there: I use what Land Rover tells me to use (which ain't Mobil 1, as should not be a surprise for a 43 year old engine design). Again, I just follow the instructions on the box, and I have a trouble free truck. You should get that looked at.

Yeh, I'm on DiscoWeb as well - Mobil 1 is on the LR approved list, just not 0W40!! Runs like a dream - self rust proofs and provides waterproofing for my driveway LOL Mobil syn in the engine, diffs and T-Case, and ATF - Mobil syn grease for that matter. Did I mention that I support Mobil's top line with my yearly lube schedule?

Of all the Land Rover quips, this is my favourite: "Don't worry if it leaks. Worry if it doesn't leak, because that means it's out of something."

So true! As long as it doesn't leak in another way when doing this! Did you know that for 60% of the developing world, the first vehicle they saw was a Land Rover? But we digress - putting a Qt of Dino in with your Syn oil won't hurt your 996 You're good to go gregroselli - wait until the next oil change then worry about which oil is best