I would also guess PS fluid. Your car came with Hyundai PSF 2 or 3. It is hard to find that now as most dealers only stock PSF 4.
There is a tsb out there about changing from 3 to 4. My 2011 came with 3 and I just changed mine over to redline PSF. After hours or research, it appears that redline is closest synthetic formula to the old non synthetic hyundai PSF 3. No moaning from car at below 0 so far, but the real cold stuff has yet to happen.
If it was my car, I should just switch to a synthetic PSF like hyundai PSF 4 or redline.
There is a tsb out there about changing from 3 to 4. My 2011 came with 3 and I just changed mine over to redline PSF. After hours or research, it appears that redline is closest synthetic formula to the old non synthetic hyundai PSF 3. No moaning from car at below 0 so far, but the real cold stuff has yet to happen.
If it was my car, I should just switch to a synthetic PSF like hyundai PSF 4 or redline.