Oil Specs from Manufacturer vs Oil compaies?

[Booki]

Originally Posted By: mjoekingz28
Originally Posted By: Booki
I am aware that we in AUS rarely have "freezing" temps, so oil weight is not something we have to worry about changing year round.

Was just wondering why some companies would recommend a 5w oil for a motor that is i guess "designed" with a 15w oil in mind.

Could running a oil too thin on the "W" rating cause any damage or increased wear?



It is MY understanding that the lower W number is better for winter, but not as good for summer.



Liken it to this, at a racetrack in the desert do you want a 0w-50 or a 20-w50?


Technically - I guess it wouldn't matter if the oil was at operating temp as they should be the same thickness/viscosity.
That said if u were going to beat on the engine cold, I don't know :\

 

[OVERKILL]

Originally Posted By: mjoekingz28
Originally Posted By: Booki
I am aware that we in AUS rarely have "freezing" temps, so oil weight is not something we have to worry about changing year round.

Was just wondering why some companies would recommend a 5w oil for a motor that is i guess "designed" with a 15w oil in mind.

Could running a oil too thin on the "W" rating cause any damage or increased wear?



It is MY understanding that the lower W number is better for winter, but not as good for summer.



Liken it to this, at a racetrack in the desert do you want a 0w-50 or a 20-w50?


Mobil's race oil is 0w-30 and 0w-50

For Road/Track use they recommend their 15w-50 or 0w-40 products.

20w-50 is a "dino" grade. The 15w-50 synthetic probably has less VII's than the 20w-50 does.

 

[Booki]

Can you go too thin of a "Winter" rating and damage your engine?

As far as I am aware, oils don't get "thicker" when they warm up, the case of 5w-40's compared to a 15w-40, they should both be a 40 viscosity when warm. just the cold properties are changed, so that said.

Why would a manufacture recommend a thicker winter rating oil, when you could just run something nice and thin to get it flowing around alot quicker?

I mean in australia, in parts where i live our coldest winter day's will be between 3-8 degree's C. I have no idea how much better a 5w would flow over a 15w in these temp's, or if the difference is even negligible.

Just sounds like you want the thinnest oil on start up and want it to keep its rating at temp.

So can you damage a car by running too thin of a "W" weight?

 

[Shannow]

Please reread the answers to your thread...they were anwserwed.

No, the 5W won't "flow" any more oil at 3-8C than the 15W, because your engine is lubricated by a positive displacement pump, and the pumpability, the ability of the cold oil to get into the pump, of either "W" rating are not tested by Australia's coldest temperatures.

 

[CATERHAM]

Originally Posted By: Shannow


No, the 5W won't "flow" any more oil at 3-8C than the 15W, because your engine is lubricated by a positive displacement pump, and the pumpability, the ability of the cold oil to get into the pump, of either "W" rating are not tested by Australia's coldest temperatures.

Not true.
The oil pump has a relief value that limits maximum oil pressure and therefore oil flow when activated. So yes you WILL have greater oil flow on start-up with a 5W-40 or better still a 0W -40 vs the very heavy Dino 15W-40 even at moderately cold 3-8C temperatures.

Booki your thinking is on the right track.
Even a 0W-40 is way heavier than necessary when starting cold at those temp's but it's major improvement over the obsolete 15W-40 grade.
Not surprisingly that grade is no longer specifi d by any manufacturer for the US, European or Japanese markets.

 

[wemay]

Here we go....