Hello folks

My 2017 Santa FE 2.4 engine GDI had a engine knock sensor go bad, got it fixed, problem returned again, then I was told it was the wiring, all which got rep[laced under warranty.
A week later the same issue again, only this time the dealer says the engine is carboned up and the head need to be pulled so the can clean the valves. Not under warranty !!
This car has 38,000 km only. It's driven most of the time at highway speed.

They also say I should always use premium fuel as opposed to the Hyundai operator's manual which states that you should use regular gas

Any opinions

Michel

 

As I understand it,
With GDI (Gasoline Direct Injection) the fuel is no longer injected over the intake valves, which kept the carbon from accumulating on the valves.
Now, with GDI, fuel is no longer injected near the intake valves, but directly into the combustion chamber. The Oil vapors from the engine are pulled into the PCV system which sends those vapors past the intake valves and carbon builds up on them and now causes performance problems. Some manufacturers have developed an add on system that collects those oil vapors and sends the accumulated oil back into the oil pan reservoir.
If it in the combustion chamber, a tankful or two of premium will usually clean the carbon out of the combustion chamber. That tank full of premium does more by also cleaning the injectors , so it is not a bad move to do maybe every 4 or 5 tankfulls to make one of them premium.

 

Try another dealer, it may be the engine going bad as per the recall. I have not heard if carbon buildup so bad it causes a knock on these engines. I have heard of performance problems because of a carbon buildup on the valves though