Viscosity measurement

[Ether]

If an oil had a cold starting thickness of 84cst @ 40c,would it be a little thicker at a typical outside ambient temperature of say 20c when starting the car?

 

[Drosselmier]

yes.

 

[Ohle_Manezzini]

84 cst at 40C, isn't that thick, to be affraid.

 

[Ether]

Thanks Guys

 

[barryh]

If you know the viscosity at two temperatures or the viscosity at one temperature and the viscosity index you can use a calculator to get the viscosity at any another temperature.

http://widman.biz/English/Calculators/Calculators.html

 

[Ether]

Very useful,thankyou

 

[weasley]

Originally Posted By: Ether
If an oil had a cold starting thickness of 84cst @ 40c,would it be a little thicker at a typical outside ambient temperature of say 20c when starting the car?


Viscosity at 40°C is not the "cold starting thickness". Viscosity is measured at 40°C mostly to allow the determination of the viscosity index, in combination with the viscosity at 100°C (which you need for the SAE viscosity grade and other specifications).

Cold starting viscosity is covered by the CCS viscosity ("cold cranking simulator").

Anyway, pretty much any and every liquid gets thicker as it gets colder, so any oil will be thicker at 20°C than at 40°C. I'm not sure what you would do with this information though?