bgiere

You don't understand viscosity and how ratings work...there a number of technical papers on the subject that you would enjoy reading. and 15w50 was never an original fill...it is not, and was not availble in Germany...it may have been a 5w50 M1 at the time...

Ubermensch

[QUOTE=1999Porsche911]Well, you have my recommendations from 35 years of exoerience, but run what you want. [QUOTE]

May I ask what your 35 years of experience are in?

10 GT3

My engine has always run 0W40 Mobile One and has no issues. I also live in a warm climate (it is 106 today) and my car has never been out of Texas since new. I have no jerkiness in my Variocam as described above nor any of the other problems mentioned above. My car does consume (not burn) some oil, especially on the track. On a single day at the track, I can consume an entire quart of oil. These engines are designed to consume oil as normal per Porsche and is plainly stated in the owner's manual to do so. If you are not, I would be extremely concerned that there is a problem with the cylinders getting lubricated that could lead to a major engine failure. The thin oil is intentionally used by Porsche to complete lubricated the cylinder walls to reduce wear in the flat 6 engine. In fact, it is thicker oil that can damage internal components from not flowing properly due to the flat engine design. It is clearly stated in the owner's manual to not run the engine over 4200 rpms when the engine is cold and until the oil has warmed up for this reason.

If my car was leaking oil, the fix isn't to run thicker oil that can't leak through; it is to fix the seal and actual cause of the leak. If you have a hydraulic lifter that is leaking or sticking, again the problem is with the lifter; not the oil. There is a lot of misinformation in this thread. Not only does Porsche recommend Mobile 1 0W-40, but VW, BMW and Mercedes all use (as delivered OEM) and recommend this same oil for their performance models.

Why? Here is the spec sheet on Mobile 1 0W-40. Compare the hot and cold viscosities to your other oils:

http://www.mobil.com/USA-English/Lub...il_1_0W-40.asp

Here is one of the independant tests run on this oil against the best performance oils including Royal Purple Racing 21. Not on did Mobile 1 0W-40 make the most power, it did so with one of the lowest wear levels measured.

http://www.performanceoilnews.com/oi...nst_oils.shtml

1999Porsche911

You're wrong. The early 996 WAS factory filled with 15W50 here in the States. Boy, for being so sure of yourself, you could't be more wrong. Rather than challengining everything I say (which you seem to enjoy doing), why not do a little research or maybe offer you're own suggestions rather than simply say mine are wrong.

For example...do you know what the percentage of engines that burn and/or leak oil are running 0W40? Might be a nice poll to conduct. How many dealers in the south actually use 0W40 in the summer. Calls to 17 of them south of the Mason/Dixon line indicated that only 4 of them do..even under warranty. WHY? Which oil will provide better shear protection in hot tempertures and less leakdown, 0W40 or 5-15W/50? That is a proven answer.

1999Porsche911

So what's the difference in consuming oil or burning oil. That's a new one for me. Burning oil, or "consuming" oil as you put it, is par for the Mobil 0W40 many times,especially at track temps. Unless you are leaking a quart of oil at the track, you are losing it into the combustion chamber, robbing you of power and increasing your knock risk. Try moving up to a 15W50 and see what happens.

Of coarse you'll get more power with a thinner oil, but at what cost. The amount of oil being mixed in the combustion chamber with your fuel probably is offsetting any gain you might get.

JasonAndreas

Steve did a pretty good job.

Or as was the case with every other model 911 previous, they changed the oil spec/factory fill about two years into production time once/if they received enough data to warrant a change.

1999Porsche911

Steve made no arguement for a 0W oil, but a 5W oil. I still am waiting for someone to give a valid reason why you should run a 0W40 oil.

nycebo

I was reading around on the internet to get some different perspectives on oil viscosity and many of the authors suggest that lower weight oils are now recommended because engine clearance tolerances are much tighter than in the past and as such, a lower weight is recommended, if indeed not preferable to a higher weight which may cause damage to the bearings and seals. I don't want to aggravate anyone here with this information because I'm not much of a shopsmith, but the arguments for both sides do make some logical sense. I guess the argument for a higher weight comes down to how hard one is driving the car at how high a temperature.

Anyway, here's the link to the article. Yes, I know it's an Audi site but it sures seems that the rationale still applies. Here's some highlights:
Pretty interesting stuff....

bgiere

I surrender again.....

1999Porsche911

You're not French, are you?

Cydog

Today I spent time trying to track down Mobil 1 5w50 oil here in the US; only Mercedes Benz dealers can order 55 gallon drums of it, and the Canadian distributors will not ship it to the US due to Mobil's restrictions. Any Canadians know of anyone who will ship it to the US?

I spoke with the tech guys at Mobil headquarters (800-662-5251), and they indicated that the 0w40 oil can be brought close to 5w50 levels by mixing 0w40 with 15w50 at about a 1 to 1 ratio. They also indicated that 5w40 Delvac won't be different than 0w40 for non-winter driving (driving in LA).

Do the warring oil factions or gurus here feel that the mixing of 0w40 and 15w50 may be a solution?

bgiere

You can run Delvac 1 or feel free to mix M1 synthetic to achieve your desired viscosity...i can send you the formula if you'd like....

rayng

I'm confused. Why would you guys run 0w oil when the manual ('01 pg 148) suggests running 10w-40, 15w-40, or 15w-50 for ambient temperatures generally higher than 50f/10c?

Regarding the mixing of oils, "all current engine oils are compatible with each other, ie when making an oil change it is not necessary to flush the engine if you wish to use a different brand or grade of oil. Since however each brand of oil has a special composition, you should, if possible, use the same oil brand if it becomes necessary to top up between oil changes."

Cydog

Update: It looks like some Mercedes dealers in the US may stock and can order Mobil 1 5w50 by the quart; the part number is Q1090134 ($7 per quart, the fill for the SLR).

Steven C.

I have one simple question here. Which Dallas dealer did DallasBoats get the thicker oil from? This may shed some light on this for me....being from Dallas.