Hyundai / Kia 2.4L Theta II GDI Engine Best Oil Sweet Spot


Thread starter
Sep 10, 2010
I doubt oil grade is going to change anything to prevent the rod bearing problems. If the passage is clogged, bearing will fail eventually. The noise test done by the dealer should have detected it already anyway.

I check the PCV and do a GDI cleaning every year. I use 0w20 full synthetic every 6000 km (anything on sale: mainly Pennzoil, Castrol or Shell) in my 2015 Optima and it's working perfectly: no strange noise, no oil consumption. This car does a lot of stop and go and short trips during Canadian winter. No complaint so far.
*0W20 or 5W20 scares me in the Theta II 2.4L GDI , I bumped up to 5W30 synthetic oil for the higher HTHS as well as to guard against fuel dilution of the GDI engine.
Feb 19, 2009
The Woods of NY
In our 13 Sonata 2.4L, i like to use Mobil 1 synthetic EP 5W20 in winter, and Mobil 1 EP 5W30 in summer & OEM Hyundai filter. 50K miles, no oil consumption, and change it every 5-6K miles. The engine sound very smooth and happy lol.
A year later, and my outlook changed slightly. I now use 5W30 Synthetic year round with a OEM filter.

This is on both the Forte 2.4L and Sonata 2.4l DI. Sonata now has 67K miles, zero consumption, and engine pulls, and sounds just like new. The Forte is not DI, and also has no oil consumption per oil change interval, and sounds fantastic for the age and miles.

I change the oil every 5500-6200 miles, 2 to 3 times on the sonata per year, and twice on the kia per year. and again on Hyundai 2.4l engine OEM filters all the way. I used a m1 oil filter for 200 miles this past OC, and I was about to make appt a dealer for a engine check over haha. the valves sounded that bad on the forte. Changed out for OEM, and the valve tick went completely away.


Apr 19, 2004
New York
I've been running 5w20 because that's what the filler cap said, but the consumption has been way too much.

I'm on '12 Sonata with the 2.4L, 135k. Getting ready to do an intake spray cleaning and swap PCV for the first time ever.

Should I go with 5w30 after this? Or jump straight to 10w40? I'm in Iowa so pretty cold winters
I certainly would go to 5w30....probably a high-mileage version.
I know that in the 08' Elantra and 08' Sonata that I serviced both seemed to prefer 5w30 from an NVH prospective. (neither had consumption issues worth mentioning...maybe 1/3 of a quart if the OCI went beyond 5K.) The 2013 Kia Optima 2.4 was a different used oil until I put 5w40 in the sump.
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