I just had my i20 N 1.6 T-GDI 16000 miles annual service and noticed on the invoice they stated filling the car with 5w 30 oil. The manual states explicitly to use 0w-20 oil. I have noticed I can now hear a ticking noise from inside the car on tick over that was not audible from inside the car before the service. I have just emailed them and am awaiting a response. What are your thoughts guys please?. Any help appreciated.