The owner's manual states 10W30 needs be used instead of 5W30 when the temperature is frequently above 86F. I live in Texas. It is above 86F frequently . The car came to me with 5W30 in it but I am wondering if I should use the 10W30?

Thanks

 

Can't go wrong with 10w-30... If you are not up north you really don't need the 5w...

If you look at the charts, 10w-30 covers a huge range of temperatures... Check your manual for more info as it has a chart showing which one to use at what recommended temperature i think

 

Many thanks. We have had some weird weather down here this year----White Christmas---first in my 45 years and very cold temps over several days but most of the time it is relatively warmer down here.

 

5/30 is fine.

10W is just a little thicker at room temp. The engine temperatue is unaffected for the most part by the outside temperature once up to operating speed. The oil doesn't care if it's 45F out of 90F, the radiator will get rid of the excess heat.

Flash points are about the same with dino oil. More important is the usage of synthetic oils with extreme operating conditions. In extreme operating conditions and very high heat like Texas, I would think a 5/40 synthetic would be the ticket for year round.

But to my point above, you won't harm anything by using 5/30. Most importantly, change the oil every 5K or so. That in itself, trumps the grade used.

 

Couldnt agree more.

I use 5/30 all year long in Chicago.