What is cSt value ?

[Dogan]

hi,

i wanna know what is cSt value at 40C or 100C heat viscosity
my technical english not well, i will be happy if you explain as simple as possible

for example,

castrol edge 5w-40 shell helix ultra 5w-40
viscosity@40C 81 cSt viscosity@40C 75.4 cSt
viscosity@100C 13.4 cSt viscosity@100C 13.15 cSt

so which one protects my engine @ 40C or 100C heat, higer cSt values means good ?

 

[eljefino]

As far as your bearings are concerned, they prefer around 5 to 100 cST. At freezing and below oil thickens up to many 1000's of cST which is still tolerated by your engine, though not optimal.

There is much, much more to it, than thickness, when it comes to protecting. I'll let someone else jump in on this.

 

[Dogan]

bump.

high cst value means less viscosity ?

for example

@100 degrees

blood 10 cst
peanut butter 75 cst ??

 

[Realtech214]

The higher the cst@ 40 or 100c means the higher viscosity of the oil. Most 5w30s will be about 10-11 cst@100c and about 70-90cst@40c. Cst @100c is operating temp.

 

[Dogan]

i know cst not only value help to protect my engine

but

@100 degrees viscosity

15.0 mm²/s or 13.7 mm²/s protects better ?

 

[Zaedock]

Dogan, there is much more to engine protection than a simple viscosity number. The add pack and base oil are just parts of an engineered finished product.
The type of engine, it's application, it's climate, all can play a roll as well.

Looking at the numbers you posted for the Castrol and Shell, I could take a general guess and state that these oils would protect equally in most situations.

 

[Dogan]

actually they are Motul 6100 and Liqui moly superleichtlauf

for ford pinto 2.0 old engine which one is better ?
using with LPG

LPG generates more heat in cyclinders, and i think motul with cst 15 thicker and protects better ?

am i right

 

[Zaedock]

LPG burns cleaner than gasoline, so there are less contaminants introduced to the lubricant. It also has less energy density per unit.

Given your application (I am familiar with both atmospheric and turbo Ford 2.0L's) either oil would protect well.

I have several friends who run LPG converted engines in their off road vehicles. Many of them run a 5W30 motor oil, which is roughly 10.5cSt @ 100*C.

 

[Dogan]

now im using castrol edge 5w-40

but its decreasing, i think 5w is thin for my car and my climate never drops below -10

i will buy 10w-40 but im trying to figure out which one is right for me

 

[A_Harman]

I think for that vintage of engine with sliding cam followers, the additional ZDDP content that 40-weight oils provide will be good insurance against valvetrain wear. Another thing about LPG fuel is that intake valve seat wear can increase because gaseous fuels eliminate lubrication that is normally provided by gasoline in the intake charge.

 

[Zaedock]

Dogan, 5W40 is still a 40 wt lubricant and will be roughly the same viscosity as a 10W40 when at operating temp.

There may be other sources to your oil use such as leaks, worn valve seals, or a poor functioning PCV valve.

 

[Dogan]

yes i know this, at op. temp they almost same
but 5w in first starts causing leakings, and i didnt see 5w in users manual of my car

in my country the is no 15w-50 motul, if i find one i wanna give a try

i think 40wt is enough for me

i think i will go for motul, and many positive opininons for lubro/liqui moly

i hate when you dont know what to do

 

[Merkava_4]

Originally Posted By: Dogan
high cst value means less viscosity ?


No, more viscosity.

 

[Dogan]

cst= centistokes

i learned this now,
15 mm2/s means

can fill up 15 milimeter square in second ?