Hi,
I was talking to an Independent porsche mech today and he told me to use a 10w15 or higher synthetic, but the porsche dealer says to use mobil 1 syntetic 0w40.
He said a thicker oil is always better.
I am confused, as this is my first porsche.

Thanks,

Nafees Khaiser

 

He probably said 10W- 50. My manual says (Mobile 1) 0W- 50. The first number is about low temp viscosity (cold weather climates), so if you are in CA, NC, SC, TX, GA, FL, etc. it is not that big of a deal (in IN I would stick to >0W- ). The difference between 40 and 50 weight assuming both are synthetic is minimal IMO. This second number has more to do with flow properties at higher engine temps. The idea of overall weight and the ability to coat parts is that the thinner the fluid the more likely it will flow to engine parts right after the cold crank. The flip side is the thicker the oil, the more likely it will be stuck to the parts during the cold crank. All other things being equal, a lot of engine wear occurs on the first cold crank of an engine. The rest is based on how intense the drive (oil temp, engine temp, time of running hard, overrevving, etc.) 0W-50 usually has to be special ordered. Wal Mart carries 0W-40 Mobile by the case. Do the other things right like let the car run for a minute or two before driving, get the temp up to 180 before running hard, and let the engine run a minute or two to cool before shutting down if you have run hard. That is more important IMHO than 40 vs 50 weight. Let's see what the others think.

 

15w 50 over here in Cali...

 

Porsche reccommends Mobil 1 0w-40. I have never heard of 0-50...Anyways, cold climate or not, the most engine wear takes place at startup, so you want your oil to be a thin as possible and not honey like so that it get's to the parts fast and lubricates them. I encourage you to read this thread regarding a discussion as to whether you should have a higher low viscosity number like 15w-50 ect. After reading many articles and discusssions, I have come to believe that the lowest possible viscosity number is the best and will prove to minimize engine wear at startup...

http://ferrarichat.com/forum/showthr...6&page=1&pp=20

http://www.bmcno.org/techtip_motor_oil.htm

 

There is a Techenical Information Bulletin dated 11-30-01 that lists these oils as the only "approved" by Porsche for the 996 Turbo...

Castrol/Syntec 5W-50
Mobil 1 0W-40 and 5W-40
Sun Oil/Sunoco Synturo Gold 5W-40
Texaco/Havoline Formula Synthetic 5W-40
Valvoline/High Performance Synthetic 5W-30

I use M1 0W-40 in Atlanta.

 

I use Redline 5-30.

 

My dealer told me that they use 15W-50 in all their oil changes. They're still getting $8.00 per qt.

 

That's strange since Porsche does not recommend that viscosity range...

 

My dealer uses Castrol/Syntec 5W-50

 

Thick oil is *not* better, any more that thicker blood would be.
In fact, thin oil is very important because it flows quicker at
startup, and will lubricate all the fancy expensive valve train
parts quicker than a thick one will. You get higher oil pressures
with thick oil, and some folks think high pressure is better, but
it's really like blood pressure. All it says is that the pump has to
do more work.
The value of thick oil, *when engineered for*, is that the film
thickness is greater for a thick oil under the same pressure than
a thin oil would have. If the motor is rough or loose enough to
need thick oil cushions, then thick oil will be better. Hwever, if
the motor is well-fitted and smooth inthernally, and is engineered
to finer tolerances (smaller gaps), thin oil is better. The film is
enough, and gets places faster.
Formula 1 engines run 0-weight oil. All oil gets thinner the
hotter it gets, despite the modern additives that moderate that.
a 10-40 oil flows like a straight 10-viscosity oil would do at zero
degrees, yet it flows as slowly as a straight 30-weight oil would
flow at 100 degrees. That 30-weight or 10-30 will still be thinner
than the 10-weight oil was at zero degrees, but still better than
the 10-weight at 100. Therefore, the other advantage of a thick
oil is that it's thicker hot, so if you're in a place like arizona
where the car can be parked all night and in the morning the
block temperature is already 100 degrees, a thicker oil is
appropriate.
Do what Porsche says. They have no ulterior motive in this
case, and the know exactly what is needed.
Joe

 

Here is an old post from another forum, I did about synthetic
oil... Yes, I'm an oil nut...

It is my humble and personal opinion that sometimes marketing
claims and anecdotal word-of-mouth are the dominant information source
to guide people's decisions, especially in markets which have no new
exciting scientifically verifiable news for vendors to use to try to attract
or sway buyers.
Any motor oil meeting the SAE specs will do an adequate job in a
motor under most circumstances, if the oil is changed very frequently, it
is even more so. The conditions that would differentiate superior oils
from average oils (which are fairly good nowadays) are:

1 - Long term corrosion protection. Oils have varying amounts of
additives to neutralize the acids which build up from the chemicals
caused by combustion, especially before warmup. The better/more
expensive oils uniformly have more of these beneficial additives.
Examples of the best in this category are Mobil-1, Motul synthetic,
Amsoil, and Redline. These were typically twice as good as typical
mineral-based oils such as Pennzoil, Valvoline, and Castrol.

2 - Extra friction reducing additives. Zinc, molybdenum, and phosphorus are
examples of such additives. The better oils have a little more of these than
the lesser oils The highest I've seen are in Redline and Golden Spectro, and
the least in Pennzoil and Valvoline, but the difference is actually not huge.
Interestingly, Moly is so good at this, that some motorcycles can't use it,
because it makes their (oil-bathed) clutches slip. Oddly, Redline is the only
oil (of the best oils) that has any.

3 - Stability of volume. To varying degrees, oil may be a mixture of
longer and shorter molecules. With heat and stress, the lighter fraction
of the oil can be volatile and be evaporated out. Because synthetic bases
are created in a human-controlled chemical process, they tend to be
more homogenous in makeup, and lose less of their volume over time.
The best performers in this area are Mobil-1, Motul synth., Amsoil, and
Redline. The worst I've seen are Golden Spectro and Bahrdall. This last
oil lost 25% of it's volume in a one-hour heat test!

4 - Stability of viscosity. This relates to (3), because if an oil is a mix of
light and heavy molecules, and the light ones boil away, the remaining
volume will tend to be thicker. Thick is not good. It takes more force and time to push it around the system. The best in this category are the
synthetics, with Redline and a Mobil-1 motorcycle oil being the best in
the test I saw. In this same test Bardahl changed it's initial viscosity by
more that 25%. Because 'dyno' oils are essentially fractionated (think
'sifted') from crude oil that contains everything from highly volatile gas
to heavy paraffins and tars, they tend to be a wider mix of various
molecule lengths, which in aggregate demonstrate the desired viscosity.

For emissions and fuel efficiency reasons, cars are going to thinner oils.
As long as the oil film thickness is enough to protect against metal-to-
metal contact, it need not be any thicker. Oils break down by heat, and
thicker oils get hotter by resistance to flow (viscosity). For performance
you want as thin an oil as is safe, and to go this way, you want as uniform
a base as possible so there's no variation. This suggests that for maximum
performance, a synthetic will tend to be safer.

Joe Weinstein

 

Well said Joe!!! This is consistent with what I have read and has been discussed at length on some other boards...ie the Ferrari Chat link I posted above...Thin is good!!!

 

MOBIL 1 0W40