after some reading around, i found that 5w30 are about 175 cSt at 20 deg celsius while heavier weight oils can go up to 600 cSt. a wonder how they pump that oil and what happens to those engines at cold crank. i put 1 liter in the fridge (labeled it 'gravy') not so concerned anymore. and there's the pour point.

as long as i follow the oil specs and change intervals, i'll have to trust the motor designers/engineers to have thought about cold cranking lubrication among other things. they are far and away the experts.

i also found that some oil may have no diesel api rating but their ilsac or acea rating covers usage for diesel engines