Porsche Approved Engine Oils: Can We Cut To The Chase?

After reading hundreds of oil threads/posts on the main Porsche forums, I have come to the conclusion that I am not one bit more informed than if I were just blindly picking one oil from Porsche 's A40 list. This is probably because the only two entities with deep information ( Porsche , oil manufacturers) keep what they actually know close and personal. OK. So here are a couple of issues that I wish I could get more solid information on. Issue 1: Mobil 1 . Porsche lists THREE M1 0w-40 oils on its current A40 list: * plain * "ESP" * "True Life" What am I supposed to make of this? Is one a "better" (i.e. more wear/heat/change interval-resilient) formula than another? Issue 2: "Class 4" vs." Class 3 with enhancers". Here is what I have concluded so far, after yet another talk with an oil company rep (this time Pentosin's point woman): A pure, 100% synth (class IV) is not necessarily or automatically the better choice in extending engine life or postponing catastrophic engine failure ( IMS failure, for example) than a class III. It all depends on the specific formulation of additives of the class III oil. True? Issue 3: Meeting vs. "exceeding" A40 approval. Porsche does not specify oils that are "exceeding" A40 specs. It only specifies what oils meet their specs. All of the oils on the list supposedly were put through the same identical rigorous testing at their Weissach center. What gives an oil company the authority to declare that its oil "exceeds" the Porsche spec? Issue 4: 0w40 vs. 5w-40 If I never see temps below oº F, am I better off with the thicker oil year-round? In sum, I am still quite suspicious of the many posts all over the net which keep touting mystery oils and oil classifications that will baby my 3.4 M97 engine like no others can. Then they badmouth Mobil 1 as a less than perfectly good oil choice which Porsche only retains because of the lucrative "First Fill" and lther advertising tie-ins between the companies. To that I say: if M1 were measurably inferior, and if Porsche kept it on its list, Porsche would incur considerable warranty repair cost (not to mention getting a terrible reputation as a manufacturer).

I enjoyed reading this: http://www.lnengineering.com/oil.html

I had previously read the article, and it primarily focussed on lubricating air-cooled Porsches. Key quote: Agreed, I will only choose from Porsche's current A40 list. And I assume there are all these 0w-40 on the list for better cold start-up lubrication in colder climates? Yet, the article's author seems to insist that 5w-40 weight is better under any conditions... More confusion.

This is always an entertaining topic that usually ends in frustration, shoulder shrugging and more guessing about what is the best oil to use. For peace of mind, I've decided to select a product with good cold flow rates, reasonable hot viscosity, and just change my oil every 2 k miles (or 300-400 track miles) based on information I learned from a Mobil oil engineer a few years back at a seminar. There are so many opinions and variables one could drive oneslf crazy in search of the absolute answer. I have yet to read about an oil that caused an engine failure. Maybe that might be the better way to try to answer this question! If you find the answer, please let me know! Regarding Porsche ratings... you probably can't go wrong selecting one of their recommendations, but I'm comfortable using a reputable product thats not on their list.

For issue 1 as long as A40 is on the bottle what difference does it make? AFAIK the dealer, well my dealer, puts in plain old Mobil 1 0w-40 . Regarding issue 2 I do not think any Class III oils are on the approved list. Some like to run a class V oil (ester based IIRC) because this type of oil is supposed to be the best. But far an away the majority of Porsche engines do just fine with a class IV oil. For issue 3 again if A40 in on the bottle you can then use whatever other criteria that floats your boat to pick the oil: New and Improved; Exceeds A40; Low Fat; Less Filling; etc. Last issue 4: IIRC Porsche recommends 0w-40 if the car is used in areas where temps are below -25C. Above this you can use 0w-40, 5w-40, or even 5w-50 (not a typo for 15w-50!). I've tried 0w-40 and 5w-50 in both of my cars and I really see no real difference other than with the 5w-50 in the Turbo the hot idle oil pressure is a small fraction of a bar higher. Clearly less than (estimating) 0.5 bar and probably closer to 0.25 bar. Now I say estimating, guessing, because I'm going by the oil pressure gage which has dash lines for whole and half bar pressures so I'm guessing by the position of the needle. Make life simple. Use an A40 oil. Change it at least as often as Porsche recommends and I would suggest that you change it more often. I have elected to follow a 5K mile oil/filter service schedule for my Boxster vs. the 15K mile oil/30K mile filter service interval in the owners manual. Same goes for my 03 Turbo though I do not even know what the manual gives for an oil/filter service interval. 267K problem free (save for a failed VarioCam solenoid/actuator) miles on the original Boxster engine and 107K problem free miles on the original Turbo engine.

Look in the manual. Pick an oil that Porsche recommends that you can find on sale. Buy that oil and put it in your car. Change the oil regularly. Most importantly, drive the car and forget about what oil is in it.

What type of driving do you do?? If it's 100% street driven, then Mobil 0w40 is an excellent choice. Go with it and don't look back. It's widely available, and (when found on sale or at Wal Mart) is reasonably priced. Despite what all of the fan boys of boutique oils say, it is more than up to the task of protecting a street driven M97 engine . There are plenty of used oil analyses out there to back this claim up. If your M97 sees a fair amount of use at the track, I would consider looking at Mobil 5w50. I've used this oil at the track for two seasons now with great results (based on used oil analyses). This oil will better stand up to the heat produced during this type of driving. Also, a 3rd radiator will help dissipate a great deal of the additional heat generated while driving at the track. I'd strongly recommend installing one if you will be using the vehicle that way.

Thank you all for coming to a kind but firm consensus: too much worrying about nothing much. I will buy a couple of buckets of M1 0w-40 and put the matter to rest. The one intriguing deviation from consensus: if 5w-40 or 5w-50 is more abuse-resistant, why not just use it over 0w-40? (I do one or two track events a year, otherwise just street and weekend Porsche Club drives.)

No real good reason other than 5w-40 and 5w-50 are tougher to obtain. Another reason is that you want 0w-40 when living and driving in very cold areas (sub-freezing - not applicable to many of us). Mobil 1 5w-50 is hard to find though I have 6 cases of it in my garage. 5w-40 is easier to find but in brands other than Mobil 1. Nothing wrong with using Porsche-approved (or perhaps not) non-Mobil 1 5w-40 in most situations. I don't think 5w-40 in and of itself protects any better than 0w-40, but that's just my opinion. Remember, "w" in 5w-40 stands for Winter and not "Weight" - a common misconception propagated by certain popular websites...... Hot viscosity (40) is exactly same for both types of oil. :cheers:

just found M1 0w-40 at O'Rieley's for $5.99 a quart. Don't know how long the sale is good for, so don't wait too long. good shopping anyone in SoCal- La/Oc area with a durametric willing to help with reset of dash reminder on my '08 2.7 cayman . thanx

...and that is what I bought yesterday, and where I bought it, and for that price. Thanks for the tip! Now it's on to sifting through the mess of semi-information, misinformation and rumour-milling of IMS failures that may or may not affect my car's engine, now, later, or never...

Googled "buy Mobil 1 5w-50" and found it on sale at AVlube.com for $38.61/6 pac. With shipping it still came in under $8/qt. Picked up 5 cases. Can't find it anywhere locally. About what I was paying for brand "C" (non-A40) 5w-50 locally.

I've been buying Mobil 5w50 (sold by the case, 6qts) from AVLube for a couple of years now. As noted by others, including shipping it generally works out to less than $8/qt which isn't bad.

How well does oil keep in its plastic bottle? I've had a quart of M1 0w-40 in my front trunk for the last year and a half (just for emergency). I need to add a little oil, should I use the one I've been carrying around for the last 1.5 years, and put a new one in the trunk every so often?

Quoting from an artilce from Mobil regarding shelf life of Mobil 1: "the product is safe to use for up to 5 years. Keeping it cool and dry are the key conditions to control degradation and additive drop-out." The article is here: Shelf Life on Opened Bottles of Mobil 1

FWIW the guy who preps my car and also races PCA and builds race cars recommends Mobil 1 5-40 Turbo Diesel. It can be bought in big jugs at Wal-Mart.

Bought two 5 qt jugs of Mobil 1 0-40 at Wally for $22.47 per plus tax. Works out to$4 .49 per qt plus tax. Not too bad I say.

https://apfco.com/secure/R9798W/ $12 rebate on Mobile 1 5 quarts jugs, two rebates per house so save on 2, order from an authorized retailer (advanced auto with free delivery came in at $27.99 each after the coupon code HXU5BX for 25% off). All in with PA sales tax it came out to $3.60 a quart. You can file the rebate online easily, I have been doing this each time they offer the rebate (this is the 4th time in 2 years), and even though walmart wasn't listed they did honor it the first time I found out about this rebate, as I had recently purchased without knowing about the rebate but figured I would try with my existing receipt.

^^^ I also do this rebate deal every year. I buy a couple of 5 quart jugs at Wallyworld and get the rebate. Saves a bunch of money! My wife's car also uses the same oil so it works out really well.

Me too with a 328XI, and a 330 ZHP I use more than 10 qts a year!