Interesting Article on why Hyundai/Kia GDI Engines Fail

[xrocketengineer]

Article with Video. I am glad I got rid of my Hyundai Santa Fe 2 weeks ago.

 

[DaveFromMi]

Fuel pump pressure at 2000 psi causing excessive pressure in cylinder?

 

[Fordtech86]

It’s fake news lol.

this was the funny part

“Because of these high pressures, Paul says fuel can easily leak into the valve cover and into the engine oil.”

most gas engines are direct injected these days.

edit: not a bad idea to ditch the Hyundai tho btw, they do have engine issues but it’s not from the fuel system. It could play a part but if it’s truly oil dilution then they have piston/ring/block issues with their engines

 

[DaveFromMi]

It sounds like the cylinder walls or piston rings are disintegrating. Hyundai/Kia gets high marks in JD Power initial quality, long term not so much.

 

[Velma]

Yikes wife just got a sorento. Lease tho thankfully

 

[The Evil Twin]

I think Lab Coat Paul needs to put on some dungarees and tear down an engine. 2000 psi is nothing for a TDI engine. By his theory, most diesel engines would need 500 mile oil changes with over 2.5 times the fuel pressure. Lol.
I'm not saying the engines are bulletproof. Just that he doesn't understand. Seems like he is more a metoober so I didn't give him traffic. Just read the article.
FWIW- the wife's TDI Hyundai (60,000 mi) and the son in laws Kia (162,000 miles). Don't eat oil. No fuel dilution. Worst engine repair- bad Coil at 154,000. I have checked valve clearance on both. Never needed to adjust either as of yet.

 

[xrocketengineer]

It’s fake news lol.

this was the funny part

“Because of these high pressures, Paul says fuel can easily leak into the valve cover and into the engine oil.”

most gas engines are direct injected these days.

edit: not a bad idea to ditch the Hyundai tho btw, they do have engine issues but it’s not from the fuel system. It could play a part but if it’s truly oil dilution then they have piston/ring/block issues with their engines

Watch the whole video. Don't forget that the in the GDI engines the high pressure fuel pump is driven by a one of the engine's camshaft lobe. That is why it is credible that if there is fuel leakage from the pump plunger, it would end up in the oil.
Interestingly enough, all the talk and lawsuits have been on the 4 cylinder engines, particularly the US made ones. My son in law's 2011 Sonata had the engine replaced when it just quit and my daughter's 2013 Santa Fe Sport started doing the "mystery disappearing oil" and the engine was also replaced by Hyundai. Both cars had significant mileage when the engines failed.
My experience was oddly different. My car was a 2014 Santa Fe GLS with the V6 engine made in Korea. During the first year the car ran ok while driving at relatively slow speeds when my wife drove locally. But when I drove it and tried to merge in the interstate, it was very unnerving. The engine had no power, it would rev its nuts off past 6000 RPM but the car would not accelerate nor the transmission would shift. You would have to lift your foot of the accelerator in order to get the transmission to shift, like in my dad's old Ford-o-Matic.
I complained to the dealer and they replaced a "kinked high fuel pressure line" in one of the engines banks. There was a slight improvement but it was still not acceptable to me. I kept complaining to the dealer at every "free" oil change every three months. Their answer was that it was ok, "the engine can rev up and it will not blow up".
One day coming from Orlando, I tried to merge on the 70 MPH speed limit "Beach Line" and the engine went into some kind of "Safe Mode" and would not rev past 1800 RPM regardless of how hard I pressed the accelerator. There was no "check engine light" anywhere. Fortunately, that was about 65 MPH on 6th gear and we made it home with no further incident.
I took the car to the dealer and it took them two weeks to finally figure out the problem. Another kinked fuel line and (surprise!) the high pressure fuel pump was putting out 300-500 psi when it actually needed 2100 psi.
So the high pressure fuel pump was bad from the factory. From that day on the car ran properly but it took me almost a year complaining to the dealer. No more Hyundais or Kias for me.

 

[fried1765]

Watch the whole video. Don't forget that the in the GDI engines the high pressure fuel pump is driven by a one of the engine's camshaft lobe. That is why it is credible that if there is fuel leakage from the pump plunger, it would end up in the oil.
Interestingly enough, all the talk and lawsuits have been on the 4 cylinder engines, particularly the US made ones. My son in law's 2011 Sonata had the engine replaced when it just quit and my daughter's 2013 Santa Fe Sport starting doing the "mystery disappearing oil" and the engine was also replaced by Hyundai. Both cars had significant mileage when the engines failed.
My experience was oddly different. My car was 2014 Santa Fe GLS with the V6 engine made in Korea. During the first year the car ran ok while driving at relatively slow speeds when my wife drove locally. But when I drove it and tried to merge in the interstate, it was very unnerving. The engine had no power, it would rev its nuts off past 6000 RPM but the car would not accelerate nor the transmission would shift. You would have to lift your foot of the accelerator in order to get the transmission to shift, like in my dad's old Ford-o-Matic.
I complained to dealer and they replaced a "kinked high fuel pressure line" in one of the engines banks. There was a slight improvement but it was still not acceptable to me. I kept complaining to the dealer at every "free" oil change every three months. Their answer was that it was ok, "the engine can rev up and it will not blow up".
One day coming from Orlando, I tried to merge on the 70 MPH speed limit "Beach Line" and the engine went into some kind of "Safe Mode" and would not rev past 1800 RPM regardless of how hard I pressed the accelerator. There was no "check engine light" anywhere. Fortunately, that was about 65 MPH on 6th gear and we made home with no further incident.
I took the car to the dealer and it took them two weeks to finally figure out the problem. Another kinked fuel line and (surprise!) the high pressure fuel pump was putting out 300-500 psi when it actually needed 2100 psi.
So the high pressure fuel pump was bad from the factory. From that day on the car ran properly but it took me almost a year complaining to the dealer. No more Hyundais or Kias for me.

My perception of Korea made products is somewhat dated.....but......
In my days of traveling to Korea, we called it.... "the land of almost right".
They made a lot of products, and most of them were..... "almost right".
I have not traveled to Korea in the past 25 years.

 

[The Evil Twin]

FWIW-
SANTA CRUZ, the TUCSON, SANTA FE, and the ELANTRA are the only models currently made in the US (Alabama). Engine assembly is also done here for those models with the exception of forced induction engines. The vehicles VIN will tell you where it is made. First character K = Korea, a 5 = US.

 

[xrocketengineer]

I am beginning to think that the GDI technology overall might having been oversold. The 2025 Ford Maverick with 2.0 ltr. turbo engine has lost 12 hp compared to the 2024 model. The reason is that Ford had to add a particle filter to the exhaust, just like with the diesels:
2025 Ford Maverick 2.0 ltr. turbo engine power loss
So not only the GDI engines have the issue with carbon accumulation on the back of the intake valves but now they will need an exhaust particle filter too. What's next?

 

[The Evil Twin]

I am beginning to think that the GDI technology overall might having been oversold. The 2025 Ford Maverick with 2.0 ltr. turbo engine has lost 12 hp compared to the 2024 model. The reason is that Ford had to add a particle filter to the exhaust, just like with the diesels:
2025 Ford Maverick 2.0 ltr. turbo engine power loss
So not only the GDI engines have the issue with carbon accumulation on the back of the intake valves but now they will need an exhaust particle filter too. What's next?

Delete kits. Lol!!
Edit- curious if this is in response to the ever changing (and detrimental) EPA emissions standards.

 

[jimh406]

I feel like Hyundai and Kia are just a couple of decades engineering away from being as reliable as Toyota/Honda. I'm sure someone has good luck with them, and of course, they aren't quite as much initially.

My mind says it's kind of like Kiota vs Kubota/John Deere.

 

[Fordtech86]

Gpf’s aren’t new either direct injected engines are dirty. And as far as intake build up that’s why we are running port/direct fuel systems

 

[Daylight]

In Belgium and Holland, the most reliable cars are Toyota, Kia and Hyundai...

I feel like Hyundai and Kia are just a couple of decades engineering away from being as reliable as Toyota/Honda. I'm sure someone has good luck with them, and of course, they aren't quite as much initially.

My mind says it's kind of like Kiota vs Kubota/John Deere.

 

[jimh406]

In Belgium and Holland, the most reliable cars are Toyota, Kia and Hyundai...

Do you have a source for that?

 

[DustyRusty]

Do you have a source for that?

From his location 6860 is a municipality of Wallonia, located in the province of Luxembourg, Belgium. ... Postal codes. 6860.

 

[MadMike22]

I found that part of the article hilarious too! I mean, when it comes to high-pressure fuel systems, it seems like every engine these days is trying to compete for the "most complex" title. I’ve got a buddy with a Kia Optima engine, and he’s always joking about how it’s like a ticking time bomb with all the issues popping up.

It’s interesting how many people still consider direct injection as the villain, though! In my opinion, while it can contribute to some problems, the real culprits might be deeper issues with the engine, like the piston/ring/block stuff you mentioned. I think it’s more about how the whole system works together rather than just the fuel injection.

 

[BBFarmer]

Most of the time, in our shops case, Its oil consumption.

Take todays victim: 2016 velostar with 98k : Customer requests basic tune up (lol)

Now, this fine jewel came in on the hook. Misfires on 2 & 4 accompanied by multiple "double 00" timing codes.

After scoping the injectors on 2&4 ( Engine is done, heard it skipping on the starter coming off the wrecker, this was only done as a lesson for one of our apprentices) it was determined the pintle was hung closed on both injectors. This was the initial issue that they continued to drive with.

However, what got them was running the bastard out of oil. That happens because of this:


This vehicle is actually 800 miles short of its next service (5k sticker in window from previous quick lube). But, in 4200 miles, it has consumed all but a half a quart of its little over 3.5quart crankcase capacity.

So, in this case, she got low enough to back off the timing chain tensioner allowing her to skip a few teeth ultimately kissing a few valves.

Unfortunately, alot of these engines are junky throw aways. And the factory designs are bad enough that alot of your large aftermarket rebuilders wont fool with them. We've been a Jasper installer now for 15 years and even they won't touch them.

I have had 2 customers supply us with hyundia/kia engines in the past from an outfit out of texas. They come new, professionally crated, and always with a 5qt jug of castrol 20w50....if that tells ya anything.

Alot of manufacturers moved service intervals a decade plus ago. And alot of these engines going 5k, 7500k, and even 10k intervals are destroying themselves. Just another way to keep the world going around and make sure you keep coming back buying new vehicles.

If they can make that vehicle fail around the 100k mark (3-5years) and get you back into another loan, they win. And i believe, this is what manufactures/engineers are able to now do.

It does them no good selling you a vehicle that will last you the next few decades.