I have a 2006 Hyundai Sonata LX, 6 cyl sedan. I need help on which viscosity of motor oil to use. I looked in the owner’s manual, and there are several options, which really doesn’t help. I live in New Jersey, where the temperature could reach 100 degrees in summer and single digits in winter. At the present time I’m using 10W30 all year, but I’ve heard that it’s better for the engine to use a thinner oil in winter (5W20) and a thicker one (5W30 or 10W30) during the summer. I would appreciate all recommendations on this subject.
You are not in an area that would be considered unusually hot or cold. You are safe using the standard recommendation in the owner’s manual. (10X30?) If you like and plan on changing the oil twice a year go ahead and use something with a little more cold capability (that is the first number, nothing to do with the second) in winter and something a little heat resistant (the second number, the first is not part of summer heat). I don’t bother.
For New Jersey, a good 5W30 will sufice all year round. Your owner’s manual usually has a range of temperatures with the recommended oil viscosities.
You must use an oil that’s listed in your owner’s manual if you want to keep the warranty in effect, so ignore what others might have told you (and by others, I’m not talking about the other two answers here - they’re good). What options does the manual list? NJ make have short-term hot and cold spells, but it’s not unusual overall, like the previous person said.
5w-30 is good all year round pretty much anywere in the continental US for most newer cars. During the winter you can get away with using 5w-20 and doing so may or may not result in better gas mileage, but there is no harm in using 5w-30 during the winter.
the manual,is correct,dismiss all else.