The Hyundai/Genesis/Kia 3.8-liter Multi-Port Injection (MPI) V6 first appeared in 2009. It is the largest engine available from these manufacturers. Since then, there has been an update to Gasoline Direct Injection (GDI) called Lambda II GDI. It first appeared in the 2012 Hyundai Equis, Genesis, and Kia K9. The Lambda II GDI continues to be used in many models today. While a proven engine with lots of power and torque, it has common problems, as most engines do.

The Hyundai 3.8 MPI V6 engine delivers between 286 and 312 hp. It’s a naturally aspirated DOHC 24 valve with between 264 and 295 ft-lb of torque. Both the MPI and GDI 3.8 engines are basically the same, with the exception that the GDI features direct injection while the earlier MPI used port fuel injection. 

3.8-L Lambda II GDI engine carbon build-up

With the switch to direct injection in 2012, the V6 saw better performance with increased horsepower partially due to an increase in compression. As we’ve discussed with other direct injection technology, carbon buildup is a problem.

The MPI V6 sprays fuel into the intake ports and intake valves. So the fuel acts as a scrubber, washing away those carbon deposits that result from oil blowby. All engines produce a certain amount of blowby.

How does carbon build up on the Hyundai 3.8-L V6 engine?

But with direct injection, the fuel is sprayed into the cylinders. According to EngineBuilderMag, introducing liquid fuel into cylinders is very damaging. Without the fuel washing away carbon deposits on the intake valves and intake ports, that carbon builds up. In time, usually around 100,000, this becomes a problem. 

That’s because the buildup decreases airflow. In turn, performance is reduced and reliability issues increase. You’ll start noticing engine misfires, rough idle, and loss of power. The inconsistent air flows into the cylinders. But because it happens over time, it may not be noticeable until these issues become more severe. 

The only solution is to have the heads removed and then remove the carbon buildup. Walnut blasting is the preferred method because it cuts through the carbon deposits without harming the ports or valves. But the service can approach $1,000 or more. Still, it will happen at some point and you will notice it at some point. 

Hyundai 3.8-L oil leaks

All engines and transmissions are prone to leaks as the miles pile up. With the Hyundai 3.8-L V6 engine, a common issue is oil filters not being attached properly. Usually, it is related to an oil ring or drain plug. So if you start noticing oil under your car after an oil change, it could be this simple problem.

When the miles build-up, oil leaks can come from valve cover gaskets, oil pan gaskets, and main seals. Besides oil spots on the garage floor, a burning smell and light smoke behind the car, are how some of these leaks manifest themselves. 

Hyundai eight-speed transmission issues

Though not related directly to the 3.8-L engine, Hyundai made a transmission change in 2012 when the GDI engine came out. A new eight-speed automatic added to performance and mileage numbers. But there were some problems with these early eight-speeds. The extensive warranties that come with Hyundai/Genesis/Kia vehicles took care of these problems. Still, you should be aware that there were transmission issues, mostly with 2012 models.