Mobil 1 0W-40?

[Smallblock454]

Hello Gelbster,

that is true, and there are so many oil discussions on the internet. But i also don't have a clue for that, because i can't tell how much longer the engine will live or if there is a difference in the end. Also the oil compositions change from time to time. And some believe in that brand and some in the other brand.

There are some technical and logical factors that can be brought into the discussion, but that's it.

For example:
The engine is mostly made from aluminium. Mineralic oil tends to generate aggressive acid if you use the car only on short distances, because it contains sulfur. So in the case a full synthetic oils is better. But on the other side sulfur is a good lubricant additive.

Viscosity. Some say you need a 0W oil, because it is very thin and will oil everything immediately. But if we look a little bit closer we will see that the xW factor is defined by the norm SAE J 300. This norm says that the has to be pumpable at these temperatures:
SAE 0W −40 °C
SAE 5W −35 °C
SAE 10W −30 °C
SAE 15W −25 °C
SAE 20W −20 °C
SAE 25W −15 °C

So i think in normal climates or if you don't have cold winters or if you only drive your car in summer season a SAE 5W or 10W oil will also be good. Also you can hear the difference when you start a cold engine and the hydros are quite o quieter – which means more oil pressure or that the oil didn't run out of the hydros because it's to thin. And in general the engines we have are not new and have some wear.

Longlife oils: Longlife oils are not designed for short distance driving. So if you only drive short distances it is better to use a standard full synth oil.

And there are oils on the market that are different from standard oils. For example ester based oils.

Tribology:
Motor oil in general: https://en.wikipedia.org/wiki/Motor_oil
Kinematic viscosity at low and high temperatures - https://en.wikipedia.org/wiki/Viscosity
Viscosity index: which is mostly declared in norms - https://en.wikipedia.org/wiki/Viscosity_index For example ASTM - https://en.wikipedia.org/wiki/ASTM_International
Dynamic viscosity - https://en.wikipedia.org/wiki/Viscosity#Dynamic_viscosity
Density - https://en.wikipedia.org/wiki/Density
flashpoint: the higher the better – also depends on upper viscosity value - https://en.wikipedia.org/wiki/Flash_point
Pour point: Indicates the temperature when a fluid is barely fluid - https://en.wikipedia.org/wiki/Pour_point
HTHS: high-temperature, high-shear
Additives: that is an endless discussion

And still i can't tell you which is the right oil that will make your engine last longer.

Regards, Markus

[imon_2nd]

Another data point on Porsche oil:

The only Porsche dealership, Niello, in our metro area of 2 million people services a lot of Porsches of all types. I took my "new" Boxster in for an oil change knowing they would search the car for anything broken or worn out so they could propose repairs. I was surprised they used Mobil 1, 0-40W on my 100K-miles car. When I questioned the wisdom of this choice, the service manager said that was what they use on every Porsche, new, low-miles, or old, high miles. They've been doing this since 1981 and claim "no problems."

0-40W is not what I'd have selected, but on the other hand, I haven't noticed any camshaft chain noise or valve clatter at start-up.