bearone

yeah i think the manuals were in the cars when delivered.

no leaks, from what i've heard you're the exception, let's wait and see if anyone else chimes in with no leakage.

how long ago did you move to synthetic, how many miles were on the car?

seattle doesn't get real hot or cold so 0-40 works well.

i doubt very seriously if many, if any 944/951's, are running 0-40 in phx, az, last weekend it hit 114.

i used 20-50 valvoline synpower in hawaii because the po had rebuilt the eng and recommended continued use, same diet in phoenix.

87951
95sl320 dd

seattle951

I sold my 924S two years ago when our son was born. I picked up a BMW 740il since it was larger and we felt it was safer with a baby seat. Before he came along, the 924S was my daily driver.

I probably put 50,000 mile on it over 4 years. The mileadge was either 80,000 or 180,000. I changed to synthetics about 3 months after purchasing it. It ran for 4 to 5 years without a leak up until the point where I sold it.

seattle951

Putting the tolerance issue aside, would running a lighter weight oil help with cooling and thus could be better in hot climate?

Pumping a thick oil requires more energy than pumping a thin oil. The energy differential is retained as heat increasing the oil temperature and engine heat.

If a thicker oil flows a lower volume through an oil cooler, the oil cooler is less effiecient resulting in more heat being kept in the engine. (Bad thing)

Wouldn't it make sense to run the lightest weight oil possible that meets requirements for film stregnth and lubrication? You would only want to move to the thicker oils once heat levels have exceeded the thin oil's ability to provide desired film stregnth and lubrication.

As oil technology improves, new thin oils will be able provide heat performance that is superior to the previous generation of thick oils. As time goes on, you may want to move to thinner and thinner oils to take advantage of technology breakthroughs.

Of course, if worn engine components and tolerances is driving the decision, this point is mute.

bearone

"Wouldn't it make sense to run the lightest weight oil possible that meets requirements for film stregnth and lubrication? You would only want to move to the thicker oils once heat levels have exceeded the thin oil's ability to provide desired film stregnth and lubrication."

you've answered your own question of why folks run 20-50 in a hot climate even though it's contrary to porsche's newer recommendations.

87951
95sl320 dd

Fishey

There is a thing called oil pressure you might want to consult with it.. lol!

Sure, you can run thinner oils but the car was built to run thicker oils and as a result its oil passages/lifters/etc are made to run thicker oil. As you mentioned thinner oil will drop resistance and less force will be needed to move the oil though the system. This means your getting less pressure throughout under the same conditions. You do have a OPRV but eventually when your oil gets so thin it simply will not have the required pressure.

carlege

for a street car that isnt running high rpms all the time it wont make much of a difference. Unless your running close to oil chemically breaking down temps it shouldnt matter. Lower weight has been proven to show lower oil pressure in hot climates on older engines. Ive read of a couple cases where they switched to a heavier weight and it restored adequate pressure at idle rpms. Cooler oil is nice but if its not getting through the engine then thats a bigger problem


EDIT: Fishy beat me to it LOL

V2Rocket

20w50 here, temperature ranges from 60-100 but generally is mid 70s here. in the middle of winter in the mornings it has dropped to the high 30s but never have had any issues with oil pressure or starting the car or knocking or anything

seattle951

Is there a published temperature chart that shows where 0W-40 synthetic loses its effectiveness that we could compare to a 951 operating temperature in different environments?

My understanding is that the 951 does not get hot enough during street driving anywhere in the United States in the summer to exceed the capabilities of modern 0W-40 synthetic. This was a contributing factor to Porsche's new recommendation for this weight oil for cars in the U.S.

seattle951

As mentioned, I am running 10W-30 synthetic. On the hottest day, I have never seen pressure drop below 3 bars at idle. Pressure climbs quickly past 5 bars when rpms pick up. Of course, everything is new in my engine and tolerances are tight. Other cars may be different.

333pg333

Here you go. Sit down and read all about it. Might want to make a sandwich first though....

http://forums.pelicanparts.com/showthread.php?t=367300

Fishey

Mobil 1 15w-50 and RotellaT have around 1,200ppm of ZDDP

15W50 is the most of any M1 oil...

333pg333

We use 25w/60 for the track.

dillon410021

holy ****, you would need more than a sandwich to read all that ****

seattle951

Since you have already read the thread, will a stock Porsche 951, with reasonable amounts of engine ware, running in 105 degree weather under aggressive street driving conditions exceed the capabilities of modern 0W-40 synthetic oil?

My assumption is "no" or Porsche would not be recommending this oil for the 951 in the United States.

zoltan944

"Hi, I will take 9 quarts of the Harley Davidson 20-50 motor oil please!"