You have been warned. Don't buy a GDI and definitely don't buy a GDI hybrid. We have a 2018 Hyundai hybrid sonata. GDI has a tendency to soot the oil and wash down gasoline into the oil. I have been having a problem with it on our car. Hybrids that constantly start and stop make the cylinder wash down worse. Hyundai recommends 7,000 mile oil changes. First winter we had it. Twas late winter, oil change had about 4000 miles on it I went to check oil and noticed the oil stunk of fuel. I changed it and sent off a sample to be tested. Test came back and said there was 5% fuel in the oil and that was diluting it to to like 0w-10 oil, yeah that shit will wear your engine out too. My solution: do a summer and winter oil change. The fuel wash down is much worse in winter. For summer Fill the recommended 5w-20 oil to the low mark on the dip stick. After about 2,000 miles add a 1/2 qt of 20w-50 oil, 2,000 miles later at about 4,000 miles total add another 1/2 qt of 20w-50 oil, get 7,000 to 8,000 miles out of the summer oil. Winter, fill to the low mark, after 1,000 to 1,500 miles add a 1/2 qt of 20w-50, another 1,000 miles or at around 2,000 to 2,500 total add another 1/2 qt of 20w-50 oil, change at 3,000 to 4,000. Other things I do, run it in sport mode on the highway during the winter as much as possible. "Sport mode" doesn't cycle the engine on and off nearly as much, the engine almost always stays running in sport mode. I do the sport mode thing about once a week during the summer.
It is worth noting that to keep your Kia factory warranty, you MUST change the oil 2x a year. No matter the milage. I got a used (2019) when it was just a year old and paid $750 for the lifetime oil changes. The dealer gets $85 for the change - cheapest place in town. This is the last car I'll likely ever own. My last - a 1997 4 dr Sidekick was driven for over 20 years before retirement. Should have spent the money for minor repairs, but the rust was catching up... And yes, I check that the oil of fresh/clean after each change.
Yeah, GDI engines not great. My buddy is a mechanic and dealt with a lot of carboned up valves and diluted oil (now burns oil and low oil pressure) Some manufacturers use a dual system GDI and Port injection. Those systems can be found on a number of Toyota models. Way less problems. I'll not be buying a GDI only model .. especially not used. If you get a GDI engine, change that oil religiously and early.
We've had at least two customers get free engines due to lubrication issue. I would advise against getting one, used or new.
You don't have to change the oil if you can keep the viscosity up. First I tried filling up to the middle of the full mark and topping off with 10w-40 half way through and that wasn't enough, still too thin at oil change time. Next oil change I filled to the bottom of the full mark and added a qt of 10w-40 half way through the oil change, that was barely enough to keep the viscosity to 5w-20 with 3% fuel in the oil. Running it in sport mode on the highway proved to reliability get the fuel in oil dilution from 5 to 6% to more like 2 or 3% in winter. Then I said f it and used 20w-50 to top off and that was it.
But the dilution with fuel is only part of the issue. Metal particulates accelerate the damage, causing catastrophic failure of connecting rods...aka a hole thru the side of the block.
The oil tests shot no unusual metals with the thicker oil. The fuel diluted oil showed some additional wear metal in the oil but it was caught very early.
there is usually a reason the new GDI engines specify 0w16 or 0w20. not sure that adding 10w40 is the solution. But I didn't design the engine. Older engines that we grew up with were a lot more forgiving. 20w50, 15w40, 10w40, 10w30 could be interchangable depending on operating temperatures and didn't seem to cause a problem with the open tolerances. Thick oil + variable valve timing + DOD/AFM/MDS + variable output oil pumps in todays modern close tolerance engines, sounds like a future engine rebuild in the owners future and probably a hard time to get it done under warranty.
I had it tested and oil diluted with fuel but thickened with 20w-50 added was closer to the right viscosity than the diluted oil alone.
Good info. Never knew that about GDI engines. I checked on my wife's car and it uses both GDI and Tuned Port injection with the engine option she has. Models with the next larger engine options have GDI only. That was a matter of luck because we didn't know at the time we purchased it.
While we were in Florida we rented a Jeep Cherokee. It was flat awful. Whenever you stop the car the engine stops. You can feel it restart when you move. In traffic, this is merely annoying, but if you have to pull out or turn left, it's quite scary. It feels like maybe you won't start in time to clear traffic. The set up of the dashboard is also terrible. My husband's right knee scraped the dash if he was close enough to move the pedals. Enough so that I drove much of the time, which is unheard of, he hates it when I drive. We have friends who swear by Jeep Cherokee, and my Kia is getting old, so we had considered buying a Jeep. I guess it's good we got this test drive. The Sorento is so much cheaper than the Cherokee, but for me the dashboard makes a lot more sense and this weird eco thing would drive me nuts. One downside of the sorento is that the battery just suddenly died when it was four years old and the cheapest replacement we found was four hundred dollars. Ouch. It's the most expensive repair we've done on the car.
Wife has that feature on her 2022 pathfinder, No idle at stop I call it, There is a button one can push to disable the stop/idle but it does reset itself every time you restart the engine,
This time I changed the oil at about 4,000 miles. It had less than 0.5% fuel in the oil. I added a qt of 15w-40 oil and that didn't significantly increase viscosity. It's not the fuel thinning out the oil, I think something in the engine is shearing away the oil viscosity. I filled the oil to the low mark and I'll be sure to add 20w50 oil this time.
