What oil to buy now 10w 40 full syn Nulon is NLA?

[losh1971]

40 is not the thickness when hot though which is what I am saying.

Don't take my word for it though go ask your local garage or even Google might explain it.

 

[chrisp]

40 is not the thickness when hot though which is what I am saying.

It behaves like a single-grade 40-weight oil would at 100C. So, yes, it is like a 40-weight oil at operating temperature.

When it is cold, it behaves like a 5-weight (or 10-weight) oil. A single-grade 40-weight oil would be too heavy for a cold start-up.

 

[Fu Manchu]

Every oil thread on any forum… ever.

 

[Pollushon]

What doesn't make sense is what you've said.

A 10w is still thicker oil when hot than a 5w. Otherwise going but your logic a 15w 40 is going to be the same thickness as 5w 40 when hot. The first number is what matters if you want a thicker oil.

Happy to be proven wrong though.

First number is the winter rating, specifically cold start, second is the operating temp rating. There's lots of reputable sources online that explain the ratings. The second number is where engines spend 99% of their working life and the bit that matters most keeping the right film between your bearing tolerances

 

[losh1971]

10w 40, is still thicker hot that 5w 40. I have looked it up on some reputable sites.

 

[losh1971]

From what I've looked up, the second number is not to do with the consistency/thickness of the oil it's something else, something like fraching. If I get time I will try to find it again. It was some bloke that I think has affiliations with AmOil.

 

[J_D 2.0]

10w 40, is still thicker hot that 5w 40. I have looked it up on some reputable sites.

No it’s not. The 40 in the number is viscosity at 100degC. A 10w-40 will flow exactly the same at 100degC as a 5w-40.

https://penriteoil.com.au/knowledge-centre/Viscosity/237/understanding-viscosities/181

 

[losh1971]

Then why have 10w 40s and 15w40s? And why would there be a need for some places in the world to run 10, why not just all oil a 5w because all it really matter in the end is tbe second number. I'm not saying what you're saying is totally incorrect. All I'm saying is that 10w 40 is still thicker when hot.

 

[J_D 2.0]

Then why have 10w 40s and 15w40s? And why would there be a need for some places in the world to run 10, why not just all oil a 5w because all it really matter in the end is tbe second number. I'm not saying what you're saying is totally incorrect. All I'm saying is that 10w 40 is still thicker when hot.

Colder climates need to run an oil with a thinner W rating so there is sufficient oil at cold start up. A 10w-40 isn’t thicker when hot, it’s thicker when cold.

 

[losh1971]

Colder climates need to run an oil with a thinner W rating so there is sufficient oil at cold start up. A 10w-40 isn’t thicker when hot, it’s thicker when cold.

Hmmmm, well once I run out of my Nulon, I will try the 5w Penrite since it's a 40 I believe and see if it uses the 1L every 10k, like it did before.