Hi,

I am new to this forum.
I own a Lexus IS350 '06 and RX300 '99.
Would anyone know if 5-20 weight oil is
an acceptable substitude
for the IS?

 

yes... it is an acceptable substitute...

 

5w20 is spec'd for new hondas and some others, it'll be fine for lexus too

 

In my last oil change at the dealership, I was told that both 5W30 and 5W20 are alright for IS350 according to Toyota Canada.

However, I'll stick with 5W30 since the synthetic oil brand (Motul) that I have been using does not have 5W20.