SchnellerUmsetzer

I do short trips 15-30 miles daily sometimes 3 times a day with 2-5 hour brakes between "Legs". I am thinking of running 5W20 during the winter (it gets cold here) and a 15W40 during the summer. I use mineral oil in "Pennsoil."
I change the oil and filter every 2500 miles most ricky tic, and use K&N filters only!


Any expert thought here?

JET951

how cold does it get over there? im not even sure where you are.

special tool

Don't ever put 5/20 into your 951 - way too thin.
You can use the 15/40 year round where you are.

SD Porsche Fan

Just put 10-30 in for winter storage. I plan on starting it a couple time a month and taking it out for a good run when the roads are clear.

I've been running 20-50 in the summer but may go to 15-40 next year and run it year round.

SchnellerUmsetzer

I bought a liter of 15W40 Igip (Italian Gas station) in Venice. The car ran great with it.
Dealership recomeds 5W40 I uses 10W40. I was thinking of spliting 5W30 or 5W20 for the Winter.

I guess I was just trying to account for all the cold starts this winter!

Thom

Lutjens is right.
Forget what dealers tell you. Thin oil are fine for modern engines but not for old ones like ours.

Zero10

Use a 0W40 for the winter, and a 10W50,10W60,15W50, or 20W50 for the summer
5W20 is too thin to adequately protect our engines.

toddk911

The only difference in using oil for winter or summer usage is the "crank" temp number. Ie. the first number.

5-40 means 5 weight for start up and 15-40 means 15 weight for start up.

Once the car is at operating temps, regardless of summer or winter, you are now at the operating temp weight number; i.e the second number.

All you need to look for in summer/winter weights is the first number. The second number should always be 40 or higher.

333pg333

25/50 down under.

Mike S

If you want to get really crazy, you can use the oil that is required on my BMW M3. We have to run Castrol TWS 10W-60. Best of both worlds really. The down side is that I can only find it at the dealer for ~$8/qt.

Z-man

FWIW, I use Mobil 1 15W-50 synthetic year round. But I only drive the Porsche in the winter occasionally, when it's dry and a bit warmer.

-Z

toddk911

I think Castrol also has a 60 weight; 20w60 but it is Dino.

Zero10

Not quite accurate.
When an oil says 5W40, and another says 15W40, that does not mean that both oils have the same viscosity when hot. The 40 means that when hot, the viscosity of the oil falls within a certain range. The range is pretty broad. To standardize things however, they classify oils into general groups, so a Xw40 oil has a visosity when hot of between 36 and 44 (not exactly a 1-1 conversion but this works for an example), and when you apply this to the different oils mentioned above it normally plays out like this, the 5W40 will be more like 5W36, and the 15W40 will be more like 15W44. This is a very pronounced difference.
Not to mention, another thing comes into play here. When using a multigrade oil like a 5W40, visocosity modifiers are needed. The greater the discrepancy between the numbers (i.e. the higher the hot number and the lower the cranking resistance) the more viscosity modifiers are needed. These are additives that are used up quickly, and can result in an oil going 'out of grade' or 'out of viscosity' as it ages (is run in an engine). If you are using a 5W40, it is more likely to go out of grade on the thin side, and actually test as a 30 weight oil after being run for a while.
I could go into more detail if you like, but for the summer you want to use an oil with a higher cranking resistance so it will hold up better over time and under stress in the engine.

TurboTommy

Zero10,
The big difference in the two numbers, going out of grade is true for dinos, but not for synthetics. Synthetics don't need the viscosity modifiers.

333pg333

It seems to me that many of us get caught up in marketing propaganda such as Mobil 1. There seems to be too many engines that have had problems or blown while using this or equally low viscosity oils to be coincidental. For the sake of a few horses why not use a higher viscosity oil that our engines were designed for? Also don't worry about Porsche themselves using M1, it was thrown at them for $00.00 which was too good an offer to resist.