I have 2016 Hyundai Sonata, 56K miles, GDI 2.4 engine, non turbo. Bought this car 3 years ago, so far no issues. The only concern I have is I've been noticing black spots on concrete garage floor under both tailpipes. Inside of tailpipes seem to be too wet after car drives for short distance (not enough time to evaporate all the water from exhaust pipes). Is this normal for Hyundai? My Toyota and Honda don't have so much water in tail pipe after short distance driving, but they are not GDI. It's not oil, just regular black water.
The colder and more humid the weather, the more water you're going to get out the tail pipe.
it's burning oil, which is Hyundai's specialty, or it's running rich.
One of the by products of combustion is water. In colder weather it will condense in the exhaust pipes while the car is sitting. Depending on the pitch of the exhaust they may drip. The black stains may indicate a lot of things like running to rich or burning oil. Try taking it out on the open road and driving for a hour or two. This allows the engine to get up to temperature, seat the rings and boil off the condensation in the crankcase. In the old days I would get cars to pass emissions by changing the oil and driving on Ocean Parkway for an hour at 65 mph. This made a failing car pass with flying colors. You may be just doing to much short distance city driving in which the engine never comes up to temperature.
I know for a fact it doesn't burn oil. Black wet residue inside of the tailpipe is not slimy at all, just watery. I change oil on this car every 5k and oil level on dipstick doesn't change a bit (it does get black much sooner than on my other cars though, due to being GDI I guess). I also use Techron fuel additive every 3k since Hyundai manual recommends it. When driving on highway for 20 min there is no water in tailpipe, only after short trips. I will conclude that it's normal for short distances (5-7 mins trip to work). What' strange is I don't see tailpipe being that wet on inside after short trips on my Accord or Highlander, only on Sonata. Wonder if exhaust pipe configuration, bends, etc. has something to do with it. Maybe it's a good idea that water does come out of exhaust pipe and doesn't stay inside after short trips?
it does get black much sooner than on my other cars though, due to being GDI I guess
there's no reason why GDI should burn sootier than any other kind of injection.
Black wet residue inside of the tailpipe is not slimy at all
if the oil burns completely then it won't necessarily be slimy.
Does the exhaust smell like gas?
