I just bought two quarts of Redline MT85 which is a 75w85 oil. I feel like this will be ok for 3 reasons: 1) people on the Facebook groups have done it without any issues 2) I live in the desert and a 70 weight oil will probably be too thin and 3) this is a bog-standard manual transmission and most of them used to run 85 weight oils.
Detailed technical specs of Hyundai i30 with body type Station wagon 2010 - 2012. Engines 1396 - 1591 cc, power 90 - 126 hp, 4 cylinders, 6 (Manual), 4 (Automatic), 5 (Manual) gearbox, 4500 mm length, 1341 kg weight.
Hyundai's response for anyone interested: Upon further confirmation with the Technical Department, we have been advised the below, The oil grade is critical to the engine and Hyundai Motor Company (HMC) strongly advice against using a grade that does not meet the manufactures recommendations. HMC stipulate to use only ACEA A5/B5 ore above.
When it comes to hyundai vehicles, the company recommends using engine oils that meet api service standards – gf-4 or sn. Additionally, they advise using oils with viscosity grades of 5w-20, 5w-30 or 10w-30. By sticking to these guidelines, you can keep your engine running smoothly and avoid costly repairs down the line.
Oil Viscosity (SAE) Capacity (engine / filter) Liters: US quarts: 2.4 Theta II GDI G4KE: 5w30, 10w30, 5w20: 4.8 / - Hyundai i30 engine oil capacity. . 447 447 80 476 141 234 216 62

hyundai i30 engine oil capacity