My 2001 turbo came with 15w50 Mobil 1. Porsche removed 15w50 from the approved oils list because of problems. When cold the thicker oil caused valve train noises, I assume from the variable valve lift or variable cam timing mechanism.
I don't think 5w50 Mobil 1 is available in the US.

 

Perhaps some of us who have close contacts with Porsche can ask
them why they have ever changed their oil viscosity recommendations?
This might allay 1999's concerns for their abilities and motivations.
Joe

 

They have done it to make more money Ok, maybe not..

It was issues with the secondary tappets and cam adjuster coming apart. What is funny is on the 993 it was often recommended to run a 50 weight for the tappets. Again though they didn’t have the cam adjusters nor the secondary tappets in the system. Totally different beast.

 

Good. *We* agree that in the rare cases where Porsche has modified
their oil recommendations, it is because of equally rare cases when
they discover problems. And in these rare cases, it is Porsche that is
in the best position to get the most, quickest collected information to
diagnose the problem and address it. Therefore, in the real world where
neither Porsche nor anyone else is infallible, there is no credible source
or opinion that would support a better-informed or better motivated
source of advice than Porsche on oil recommendations for their own
motors.
Joe

 

I just fill up with 5W-40 and top up with 15W-50 just to be safe...

 

Functional description of camshaft adjuster

The camshaft adjustment system is based on the

principle of a helical sliding gear which has a
cylindrical component (3) between the camshaft
gear and camshaft stub.
The cylindrical component has helical gearing both
inside and outside. The inner gearing engages with
matching gearing on the inside of the camshaft
gear (4). The outer gearing engages with gearing
(2) mated to the camshaft stub. At the same time,
the cylinder (3) forms a piston on the side facing
away from the camshaft. This piston can be moved
by oil pressure. A number of teeth have been
removed from the gearing to ensure that the oil
pressure can act on the piston instantaneously
without loss. The component is sealed with a
sealing ring (1) and cannot be dismantled. The oil
pressure is regulated on both sides by means of a
4/3-way valve.

Is this the issue? Oil is used as a control fluid to advance and retard the VarioCam Plus. A thinner oil would transmit quicker pressure changes in the solenoid?

 

That is one of the many issues. In short yes.

 

0w40 oil is virtually the same thickness as is 5w50 OR 15w50 OIL at operating temperature so the agrument is mute.

 

The argument is not moot. Please describe how you can argue on
one hand that 0-40 is 'water' and 15-50 is the secret Porsche doesn't
want you to know, and on the otherhand you say that they are the
same viscosity at operating temperature? 0w40 means the oil flows
like a simple 0-wt oil at 0 degrees, and because of added viscosity
modifiers, it flows like a straight 40wt would at 100 degrees. A 15w50
oil flows like a 15wt and 50wt at those respective temperatures. Are
you claiming that at any higher temperature than this, all these oils
somehow start flowing the same (having the same viscosity)? If so,
there is zero advantage to the 15w50. Film strength/thickness etc
depend exactly on viscosity, which you claim is the same at operating
temperature.
Joe

 

The High Temperature/High Shear Test(HTHS Viscosity, mPa·s @ 150º C, ASTM D 4683) for mobil 1 shows the viscosity as follows:

0w40 3.6 centipoise

15w50 5.11 centipoise

Surely that would effect oil pressure control response time

 

The "water" description I use is to describe the 0W40 sitting in a cold engine and effects the bleed down of oil in the lifters. At 200F oil temp, all three of these oils flow very similarly. What the 50 weight does is provide better shear protection as the oil gets hotter. This is why I am at a loss that some of you guys don't get it. There is NO disadvatage of using a 15W50 versus a 0W40 in moderate climates...only adantages.

As for needing a thinner oil for variocam operation, that is simply bull**** unless you are going open throttle on a cold engine. I have logged the operation of the variocam with bith the 0W40 and 15W50 oil and there is exactly ZERO difference in both the smoothness or the timing of the variocams activating on a fully warmed engine.

Easy test to do if you want actual proof for yourself.

No one - absolutely no one has stated ANY disadvatages of using 15W50 oil in moderate to hotter climates except that it is NOT on Porsche's approved list. I find this thread quite amuzing that there is no technical reason provided as to why you should use 0W40 or 5W40, yet everyone just follows the majority blindly.

So I have to assume that you prefer to have a 40 weight oil in your engine when it is running at 6500 rpm and the oil temperature is in excess of 240F? I'll stick with the protection of the 50 weight.

 

Give up 1999!

 

Jim, (1999Porsche)

Are you joking us? There is no technical data?? All the oils flow the same? LOL, are you the only one on this crusade ? You know more than an German engineer, Porsche Master Mechanics, Audi, VW, Bruce Anderson, and the list goes on? You tend to only get in arguments that are vague and offer little to no fact other than your "logs" which is abstract at best. You can log all you want. How many 996 motors have you actually opened up? Based on your response about the thrust issues on the TT I suspect none. Funny how still no one has answered that issue. It sure wasn't the oil as you state.

Follows the majority blindly? Do you suggest that they follow an individual that has never posted a single picture of anything technical related to the stories you post? You suggest they listen to someone that has been caught with multiple screen names to deceive the forum? Bottom line is you do not own a shop or even work on cars for a living. These are not the old Hot Rods you are use to and your lone example of a Porsche ownership does not quantify what these cars do on a mass level. We have seen hundreds of these cars and continue to build, repair and modify them. Not to mention the corrections Porsche has made through the years clearly show how incorrect you are in your stance.

Technically, I am not an English scholar, but amuzing is spelled….amusing

 

Well, personal attacks make it obvious that you do not have an answer to my question. I have posted my reasoning so the independent thinkers can make an educated choice.

I wonder why you refuse to use Porsche's diverter valves since, according to you, Porsche engineers are the best? Are YOU saying you are smarter that they are?


By The way, it is MOBIL 1 and NOT MOBILE 1. I'm not being an ******* like you, am I?

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Use 5/40 Mobile 1. This is approved oil. If you want the list of approved oils by Porsche let me know I will post them. Porsche approves nothing thicker for the new cars. I can see if I can post them here if people would like. It is 5-7 pages long.
__________________
Stephen (Will work for HP)
01 996TT
76 911S Targa 3.6
99 R1
97 Discovery SE7

 

I have an answer Jim, I am waiting for you to tell the masses so that we know you actually have fact/proof/data on something. Normally your responses are canned and regurgitated from another keyboard war.

An independent thinker is not one that portrays himself as an mechanic, engineer or wrench when they are not. You notice you are always in conflict with everyone. Is there a reason for that or is the world always wrong in your eyes? Are you the only one that believes the keyboard trail you weave? Maybe another screen name will pop up now, eh?

An *******…LOL, funny guy. I like to pass that up and go straight to *****. I will let you know when I get there though. Can’t let you have all the fun can we? You don’t know me very well. I haven’t started. Lord do you ever get sick of hearing yourself rant and the only one…give it a rest already.