GDi and CRdi Diesel, i believe they still spec 5W-30 but i may be wrong.
In many European countries and other parts of the world, Hyundai recommends higher-spec lubricants than those specified in the US. This includes not just higher viscosity oils but also ACEA A3/B4 motor oils.
Unfortunately, Hyundai's approach in the US and Canada has been problematic. The 2.4L Theta II engine is essentially a Theta I engine with GDI replacing MPI. Hyundai did not reinforce the rod bearings to handle the increased cylinder pressure and failed to address fuel dilution and customer neglect. This issue was exacerbated by Hyundai's specification of 5W-20 oil for these engines in the US and Canada, primarily to improve fuel economy numbers and comply with EPA regulations, thus maintaining favorable CAFE numbers. By the time Hyundai recognized their error, it was too late. In an attempt to rectify the situation, Hyundai issued TCBs to dealers, recommending the use of 5W-30 oil in the NA 2.4 Theta II engines and 5W-40 in the turbocharged versions (2.0T). While most dealers adhered to the TCB and used 5W-30 in these engines, very few used 5W-40 in the turbo engines, instead opting for 5W-30, particularly in the first-generation Hyundai Genesis Coupe.
I have owned several Hyundais equipped with the 2.4L Theta I, Theta II, Lambda I, and Lambda II engines. After reviewing the European owner's manuals for these vehicles, I decided to use 0W-40 in the Theta II engines and 5W-40 in the Lambda II, both GDI engines. Consequently, I never encountered any issues with them. I regularly changed the oil every 5,000 to 7,500 miles, avoided short trips, and consistently used high-quality gasoline. Conversely, those who relied on low-quality dealership bulk 5W-20 oil, frequently short-tripped their vehicles, and extended their OCIs often faced engine problems. I witnessed several cases at my local dealership where connecting rods had exited through the block, including some hybrid models. Technicians attributed these failures to poor maintenance on the owner's part, yet Hyundai still honored the warranty.
However, Hyundai has now tightened its warranty requirements. They require proof that owners have not neglected their vehicles. Consequently, every new Hyundai now comes with 36 months of free oil changes. Although I personally would not take advantage of this, as I prefer to change my oil myself and avoid using dealership bulk oil, I appreciate Hyundai's efforts to keep vehicles on the road and reduce warranty claims.
In the United States, there is often concern among vehicle owners about oil viscosity in relation to potential warranty claims. However, manufacturers are generally more focused on whether owners are changing their oil regularly rather than the specific viscosity used, such as 5W-30 instead of 0W-20. Issues may arise if an owner uses an inappropriate viscosity, like 20W-50, in colder climates such as the northern states or Canada, which could indeed affect a warranty claim. Nonetheless, the notion that manufacturers are overly fixated on oil viscosity is not accurate. On the other hand, European vehicles present a different scenario, as the lubricants used must also carry OEM approvals.
