I have adressed this question on many adresses, but never got a really
good answer. My car is Elantra 1.6 liter, model 2003, with hydraulic
valve lifters.
I would like to use fully sinthetic oil, but there is a catch. I live
in Croatia, and for our climate (up to 36°, sometimes 40° Celsius in
summer), manual (and hyundaiwebtech) recomends 10W40 gradation oil,
but fully sint. oils come only in gradation 5W40 or 5W50 (and other
not relevant here). Diagram in the manual shows that 5W40 is good only
up to 20° Celsius, and 10W40 goes to 40 and more.
Is it true that semi-synt 10W40 is better for hot climate than full
synt 5W40? and if so, can I use 5W50 instead (it is not mentioned at
all in that diagram)?
The reason for abandoning 10W oil is because there is quite lot of
lifter tapping untill engine is warm, and I am hoping to improve that
with synt oil.