single grade oil (SAE 40) or multigrade oil- whats the difference

[mintoy]

since i started maintaining our cars. i have always been puzzled by single grade and multigrade oils. when should u use a single grade oil (sae 40) or multigrade oil? my patrol uses 9ltrs of oil so cost is a factor (single grades are cheaper) but i'm concidering other fartors like performance and wear & tear of the engine.

[Ungas]

Maybe these past threads could help you:

- Diesel Engine Oil Specification and Price Database

- Diesel Engine Oil for Philippine Climate? Read on... there are some old links in this thread too. :D

[squala]

The single grade oil retains the same thickness/viscosity whatever the driving temperature is. The double grade one (e.g. 20W-50) obviously has variable thickness. The first number (20) is how thick the oil is when the engine is cold. W stands for winter. The last number (50) is the oil viscosity of a hot motor.

[mintoy]

so which is better for everyday driving? i use a deisel.

[speedyfix]

get multigrade oils. castrols CRD diesel oil works great and it's not too expensive pa at 100+ per liter.