Kaizu

Hello,

I drive actively the 996TT on tracks around Europe with temperatures of +5c to +30c (40F to 90F) and have used all the time Mobil 5W50.

Now the car is on a local race shop for some adjustments and I said change the oil as well, the guy uses Castrol 10W60 on Cup cars and he has put the same stuff to the Turbo as well. The 10W60 oil is for BMW M and race engines I suppose and what scares me a lot is that it is not a Porsche recommended oil.

Should I be very worried with the thick oil and change back or is this acceptable to use for half a year for my heavy track (but also sometimes street) driving purposes.

Thanks!

Quinlan

200.00 for an oil change vs. 20-30,000.00 for a new engine........I'd change the oil.

Land Jet

Kaizu, I was told by my tuner that the oil also acts as hydraulic fluid for the VarioCam actuators and that is why one should use only the oils on the Porsche approved list. Ask your tech about this. He should have more experience than I.

Hoosier_Daddy

Interesting... you have any more on this?

Land Jet

No I don't but the source was Kevin at UMW. He says 15W40-50 should never be used in the 996TT. 5W50 is on the approved oil list.

slant911

I too have heard the same as Larry. Nothing thicker than 5W on the cold temp number or you will have problems. So I would change the oil.

Macster

What more info do you need?

Since the zero-lash valve adjusters, VarioCam and VarioCam Plus hardware hydraulically operated (under engine controller controller) and hydraulic fluid is engine oil pretty obvious the engine oil is playing a major role as a hydraulic fluid in the engine.

Now whether 10w-60 oil at cold engine start would somehow not suffice as a proper hydraulic fluid that is open for discussion.

I've run 15w-50 Mobil 1 in my 02 Boxster for thousands of miles -- even in mid-Missouri winters -- when Mobil 0w-40 not available and engine and VarioCam (variable valve timing only) did not seem to be affected. Switched to 0w-40 after moving to CA though not all at once. Tried to stick with 15w-50 in the summers here (when temps can climb to 100+F on occasion) but always seemed to get caught with the wrong weight of oil at oil change time or with the wrong weight of oil in the engine so moved to running 0w-40 year round.

More recently have been using Mobil 1 10w-40 "high mileage" oil in same car.

Roughly, I've put maybe 80K miles on car using 15w-50, then maybe another 100K miles on car using mostly 0w-40 and the rest (car now has 225K miles) using 10w-40. At no time did I ever detect any signs the engine and its hydraulic system needs not being met by any of these oils.

With all 3 oils, I have started the engine and then have driven the car in a wide range of ambient temperatures from a low 0F (maybe a few degrees lower even) to a high of 116F in the desert southwest and engine has not appeared to have suffered any.

However, if OP wants to be "safe" then all he has to do is drain oil from sump and refill engine with 0w-40 oil. I'd not bother to change filter cause the small amount of 10w-60 oil in it (and throughout the engine) not significant enough to worry about.

Sincerely,

Macster.

wross996tt

mr. macster...I am very confused...is what your posting a 996TT (it seems to be a boxster?)? If not then your discussion is moot (no comparison between the boxster and 996TT)...if so then congrats on having one of the highest mileage 996TT I have ever heard of.

Macster

I own both a Boxster and a 996 Turbo. I was relating my experiences with the Boxster running a variety of Mobil 1 oils under quite varying conditions.

The Boxster engine and Turbo engine are different in many ways but their valve lash adjusters and variable valve timing hardware are quite similar.

And both engines use plain (hydrodynamic) bearings at the crankshaft, rod, piston pin and camshafts. Based on my info Porsche specs the same oils for the Boxster engine as it does the Turbo. The engines's oil requirements can't be that different.

Both engine's hydraulic needs are close enough -- in fact this is true of most if not all modern engines -- that the experience is some value.

Sincerely,

Macster.

Kevin

Kaizu, the Castrol 10W60 is a very good oil. I don't know if you will see the benifit of the 60 weight. But the turbochargers will love you..

50F is the cut off that Porsche suggests. The more you drive your car, you will get some fuel dilution.

If the car is in the garage over night and you start it and drive to work, I really don't think you will have a problem. If you get into the 30 to 40F range during the day/ drive home you might think about dropping your oil.

Kevin

My recommendations are> South of the Mason Dixon line.. 5W50, all year round.. In the NW I run 5W50 year round>the cars stay in the garage in snow and the freezing weather. In Vegas and hotter cities one could run 10W50 or 10W60 synthetics only if choosen from the Porsche approved list. Motul 300V is a very good oil. Mobil 1 5W50 is my choice..

For the guys that own 993TT I would strongly recommend the Mobil 1 VTwin oil..

wross996tt

uh..ummm....there are NO 10WXX oil weights on "the list"....

that being said....since I'm cheap, I would leave it for the next 3K or so...

Macster

You are correct. At the risk of starting an other oil war I think this absence of 10w oils more to do with Porsche seeking to improve its fleet of engines and their cold start emissions vs. a 10w oil being just bad for the engine.

The bulk of an engine's emissions occur at start up and anything Porsche can reasonably do to minimize these it will do.

I suspect too Porsche "gaming" the emissions tests done by various countries and their emissions testing labs. By specifying a ligher weight oil at 0 degrees F as the 0w-40 or even 5w-40 or even5w-50 weight oils are Porsche seeks to lessen cold engine start oil friction and thus reduce the cold start emissions. If using lower w number oil Porsche can possibly lower its engines' emssions output and CO2 output and improve gas mileage numbers a bit too.

For one car no difference. But for a whole population of many vehicles it makes a difference. Porsche saves fines/penalties levied for worse the average or spec'd gas mileage and lowers the cars CO2 levels which means the buyer pays a smaller registration fee where CO2 output of a vehcile is factored in.

Porsche already games the system, as do ohter car makers, and this is by tailoring the PDK shift map to help the cars produce some impressive reduction in emisisons and a markely good improvement in gas mileage.

Sincerely,

Macster.

Kaizu

Thanks for the valuable responses. I called him and said change it to a recommended oil...

By the way, after a recent trip to Nordschleife I just love the car more...it may be a bit too heavy and too soft suspension and 4WD not best on short tracks, but there the car just shines thanks to the overall stability and boost...

wross996tt

....do you have any data to support this. So if I drive for say 10 minutes the BULK of emissions is at start-up? Granted the car in the off position emits very little and a whole lot more when started. If this is true why do emission centers test the car at higher rpm? I have heard from most, the thicker the oil the less smoke....is that not emission. I know there are hypotheses the reason Porsche wants you to start the car and drive it vs. idle to warm it up is due to emissions, I'm just not sure where oil comes into this. Do you have any data to support the effect oil viscosity has on emissions? Please do tell.

Don't you want less friction at start...isn't this the reason for the lighter weight oil...you should read the many posts by Doug Hillary (here and on bobtheoilguy)...see what he recommends and why.

sorry for the jack...it just amazes me how many oil experts there are and it is such a learning event