Engine knock on start up

Hello, this may not be resolvable without major tear down and repairs. If you have low oil pressure concern, the only thing you can really do that makes sense is change the engine oil to ensure the proper grade of oil is used, and make sure you use a high quality filter -- even a genuine Hyundai one. This eliminates any variables that are controllable. Beyond that, base engine oil pressure should be measured with a manual gauge and monitored to determine if there is an internal concern.