qbix

Hi,

I have heard opinions that it's better to put 5W50 to our cars. Car not driven cold weathers at all (below 0C).
0W40 is supposedly better for fuel consumption and emissions.

5W50 is more stable in higher temperatures/pressures thus better for racing purpose car.

Is it rubbish information or has some true?

neanicu

What I've been reading is that the 5W-50 has a higher concentration of Zinc,which is supposedly good for engines-at least in the older 911s,I don't know if this applies to the engine in the 991GT3...

LexVan

Mobil 5W50 is Porsche approved. My UOA's tell me that Mobil 5W50 is a slightly better oil than Mobil 0W40. Mobil 0W40 is still a fine oil. The cold starting properties of a 0 weight and a 5 weight Mobil full synthetic oil are marginally different. Both are still good for temps below zero. If you lived in artic conditions, then yes, a 0 weight might prove better. But then you have bigger issues if you live in the artic.

My goal is to use a "better" oil than Mobil 0W40. Mobil 5W50 fits that bill for me. Motul 5W40 would be another excellent Porsche approved selection.

LexVan

Actually, if you look at the Mobil data sheets, they both have the same zinc and phosphorus levels. Where the Mobil 5W50 really shines is the more robust overall additive package, and much better high temp, high shear stability. When you read a bunch of UOA's on both these 2 specific oils, the 5W50 usually has more zinc and phosphorus at the end of the drain interval as compared to the 0W40.

Again, the 5W50 is slightly better than the 0W40. All I'm shooting for is something that is "slightly better". I don't know what the "best oil is".

If you consistently run UOA's on your old oil, what you want to see is the eventual leveling off of your wear metal values (sometimes referred to as 'freezing'). They are not going up, they are not going down. And they are low/below universal averages. This pretty much tells you that you have a good oil selection, and a good oil drain interval for your motor and driving style/conditions.

neanicu

Thanks Lex.
Your explanation sounds much better than mine.
That's what I wanted to say : the 0W-40 shears faster and the protection level goes down.

LexVan

Exactly. I'm getting pretty good at reading UOA's, and can pretty much spot Mobil 0W40 in a blind sampling by just seeing the SUS Viscosity (@ 210 F) and cSt (@ 100 C).

My goal is to use an oil that is slightly better than Mobil 0W40 and have it be Porsche approved. Mobil 5W50 works for me.

qbix

Thanks for your explanation.

If Mobil 5W50 is a better oil for performance car like GT3 (high temp/press. shear stability) then why the car does not come from the factory with it? I am not talking about a better brand oil as there are contracts involved but a better oil within the same brand? The cost is marginal if none.

The car comes on semi slicks and is hair above the ground so is not supposed to be driven in cold temperatures so 0W or 5W should not matter here.

neanicu

Those that have been using Mobil 1 0W-40 for a long time and have sent samples to Blackstone multiple times for testing,noticed that after a certain mileage the oil had sheared from 40 weight to 30 weight,thus not offering the protection level recommended by the factory.
If you do not follow Porsche's ridiculous oil change intervals and change your oil every 5K miles,I think you should be fine with 0W-40.

shapiroeric

I'm at about 2,000 miles and will be changing my oil with 0W-40.....I may go to 5W-40 next time though....

DrJupeman

Are you worried about warranty?

LexVan

I worry about very little in life.

Road Racin

Will the motor consume less oil with the 5w50? Especially on Track?

rockitman

IMHO...the greatest wear moment for an engine is at cold startup....therefore it follows to have an oil viscosity as thin as possible to quickly lubricate the moving parts. 0 weight is thinner than 5 weight therefore it will lubricate the parts quicker and induce less wear and tear on the motor at start up in theory. I'm sticking with 0-40 weight oil.

qbix

I would understand switching 0W40 for 5W50.
What do you gain by taking 5W40? Worse lubrication when cold and same when hot.

kneman1

Is Mobil the best option. Are better brands out there 0w40??