2017 G90 5.0L Reliability?

[GnatGoSplat]

Always wanted a big sedan. 2017 G90 5.0L Ultimate AWD is on my short list of possible candidates.

What are common issues with the 5.0L V8 cars? Maybe my searching skills fail, because I couldn't really find any posts mentioning issues with the 5.0. Are these possibly Lexus LS level of reliable? Before anyone says if you want Lexus reliability, buy a Lexus... wife would be primary driver and neither she nor I like the looks of the previous gen LS and the current gen exceeds our budget.

If anyone has any 5.0L V8 horror stories, I'd be interested in hearing it.

As a DIYer, just wondering if anyone knows of an online or downloadable service manual I can check out. I like to see how difficult something is to work on so I have an idea of what I'm getting into.

 

[edward301]

I had a 2017 G90 5.0. Good strong engine.

 

[jda8]

Watch that review. He mentions how the 5.0 Tau V8 has won awards. It’s a great engine. No superchargers or turbochargers to add strain or cause problems. Just a smooth, reliable, naturally aspirated old school V8. I love mine. I’ve had three of them now.

 

[ogogolby]

I've had the same vehicle since introduced, not one motor problem yet!

 

[Mcc]

I've had the same vehicle since introduced, not one motor problem yet!

Likewise no problems

 

[Backslack]

The only potential reliability weakness of the 5.0's design is that it's GDI only and could have more carbon build-up in the long run, whereas say a Lexus V8 would be MPI and GDI or just MPI.

 

[GnatGoSplat]

The only potential reliability weakness of the 5.0's design is that it's GDI only and could have more carbon build-up in the long run, whereas say a Lexus V8 would be MPI and GDI or just MPI.

Coincidentally, just got back from a walk with the wife where I was explaining to her that being GDI, it might need walnut blasting at some point whereas the Lexus LS has both MPI and GDI to combat the carbon issues. I'm sure she found my explanation to be very interesting, lol. LS also has metal valve covers instead of plastic.

However, LS looks are just not appealing to us. I don't know how long a G90 can go without needing a walnut blast, but I'd guess a typical GDI engine can go 75-80k miles before needing one which would last us awhile before needing it. Might even be able to find some Youtube vids on how to DIY it.

 

[edward301]

At my office we still have a 2014 Equus with the 5.0 engine and has
92k miles, no issues at all. We also have a 2015 Equus with the same
5.0 engine and 76k miles no engine issues either.

 

[SuperKing]

I sprayed a can of CRC valve cleaner into the throttle at 100k km and there was little to no smoke after letting it sit for an hour. Either the stuff doesn't work or the carbon build up isn't that bad

 

[YEH]

HMG and GM have had fewer issues with carbon build up than other automakers with regard to DGI.

The LS 500 is a different type of flagship sedan than its predecessors or the G80, and it has below average reliability (so, you're really not missing out - notwithstanding that you're looking at V8 equipped sedans).

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[Ann L.]

I have g90 ultimate 2018. It has a TSB about oring leak. I experienced this with all fluid gone while on freeway. Wonderful vehicle, service sucks. One of major Phoenix dealerships just dropped the line due to poor sales, they can't support Genesis requirement of separate brick and mortar and separate service staff. I turn my lease in next month - only has 16,000 miles.

 

[RayM]

Got to throw some shade on all the great comments. I purchased a new G90 Ultimate 5.0 AWD new on September 28, 2020. I returned it to the dealership for noise and vibration issues on October 2, 2020. They had it for 31 "workdays days" (meaning the days the service was opened). They replaced the front AWD transmission, the left rear tire, the left front wheel bearing and battery. I took it home and drove it for about 1800 miles.
On December 25, 2020, after hard acceleration, the engine went into a "limp" mode. No RPM over 2,000, max speed 50 MPH and looses power ging uphill, now power steering. I gently drove it to the dealership where it has remained since Dec. 26. Initially, the Service Manager was calling every other day with updates and that ended last week with no calls. They have been working with Genesis Technical since its return to the dealership with zero success at identifying the problem.
The car has been in the shop for 62 days and I've had the "opportunity to drive it for about 57 days since I've owned it.
To me, this is completely unacceptable. This is an $80,000 car with a myriad of problems and the Dealership nor Genesis Technical Engineers don't have any clue how to fix it. Fortunately, in NC where I live, there are very strong Lemon Laws that address situations like mine. I have filed a Lemon Law complaint thru a local attorney to Genesis Corporate requesting all of my money back. I'll try to keep you guys updated.

 

[jcgraff]

I read on Wikipedia that the 5.0L tau engine has a compression ratio: 11.5:1.

I’ve got the 3.3 L twin turbo lambda engine. As best I can tell it has a 10:1 compression ratio. I read elsewhere that a tubocharged Subaru Impreza has an 8:1 compression ratio.

The owner’s manual says 87 octane or higher is recommended for my engine. That surprises me since it is turbocharged, and having twin turbochargers, I suspect the manifold pressure can be pretty high.

For the 5.0 L tau engine, 87 or higher is recommended, but for “improved vehicle performance”, 91 or higher octane is recommended.

I know almost nothing about car engines, but for airplane engines, the high output engines (> 200 HP or so) use 100 octane fuel. The reason I was taught is that the higher octane fuel burns more smoothly, and pushes the piston so to speak rather than banging against it (detonation). My understanding in aircraft engines is that the compression ratio is typically 10 or 10.5:1 with normally aspirated engines and 8:1 with turbo engines. The reason for the lower compression ratio with turbocharged engines is with the higher manifold pressure and intake air temperature (though I understand the lambda engine has an intercooler) is to reduce the chance of detonation.

So, that being said, since higher octane reduces detonation/knock, and turbocharged engine are more susceptible to detonation due to higher combustion chamber pressures and temperatures, I would have expected the turbo-charged engine to be more susceptible to knock and to require higher octane fuel.

From reading this webpage comparing GDI to MPI, I take away that GDI is more efficient, allowing much lower fuel to air ratio at idle and routine driving speeds, and also allows for a higher compression ratio: Technology:Gasoline Direct Injection Engine

I drove both engines before buying. I did ask here about 3.3T vs. 5.0. I actually preferred the low end of the 3.3T, which is most of my driving in the city. Professional reviewers couldn’t tell much difference either. I see the 0-60 is the same at 5.3 seconds for both engines, though the 5.0 is faster for the quarter mile. I couldn’t tell a difference in acceleration while taking my test drives, but I wasn’t flooring it for a quarter mile. The 3.3L turbo weighs about 300 pounds less than the V8, and I could tell the difference in the front end while driving on a curvy road.

I was going to go with the 5.0 based on advice given here. I brought a 5.0 home for a week while waiting for a 3.3T in my preferred color to come in from being a demo. IO decided to get the 5.0 after driving it for the week, figuring the normally aspirated engine would be more reliable. However, it sold sight-unseen while I had it. I’m happy with the 3.3T and I’ve got the 10 year powertrain warranty. I’ll likely be using the Genesis dealer long-term for routine maintenance, so the dealership’s lifetime powertrain warranty will kick in after 10 years.

 

[GnatGoSplat]

I have g90 ultimate 2018. It has a TSB about oring leak. I experienced this with all fluid gone while on freeway. Wonderful vehicle, service sucks. One of major Phoenix dealerships just dropped the line due to poor sales, they can't support Genesis requirement of separate brick and mortar and separate service staff. I turn my lease in next month - only has 16,000 miles.

Yikes, that's a little scary. This TSB? https://static.nhtsa.gov/odi/tsbs/2018/MC-10152864-9999.pdf
That's a shame about the poor service. If I get a 2017 or 2018, I might have a little bit of warranty left. There are no Genesis dealers anywhere in my area. I assume a Hyundai dealer would cover the warranty work?

Here's a question for anyone that might be a DIYer or tinker around with their cars: Is the hardware interface and software for diagnostics and coding as easy/inexpensive to buy as for BMW and Audi? All I've really found is it's called GDS for Hyundai, but the TSB mentions it and it seems necessary to have for DIY repairs.

Got to throw some shade on all the great comments. I purchased a new G90 Ultimate 5.0 AWD new on September 28, 2020. I returned it to the dealership for noise and vibration issues on October 2, 2020. They had it for 31 "workdays days" (meaning the days the service was opened). They replaced the front AWD transmission, the left rear tire, the left front wheel bearing and battery. I took it home and drove it for about 1800 miles.
On December 25, 2020, after hard acceleration, the engine went into a "limp" mode. No RPM over 2,000, max speed 50 MPH and looses power ging uphill, now power steering. I gently drove it to the dealership where it has remained since Dec. 26. Initially, the Service Manager was calling every other day with updates and that ended last week with no calls. They have been working with Genesis Technical since its return to the dealership with zero success at identifying the problem.
The car has been in the shop for 62 days and I've had the "opportunity to drive it for about 57 days since I've owned it.
To me, this is completely unacceptable. This is an $80,000 car with a myriad of problems and the Dealership nor Genesis Technical Engineers don't have any clue how to fix it. Fortunately, in NC where I live, there are very strong Lemon Laws that address situations like mine. I have filed a Lemon Law complaint thru a local attorney to Genesis Corporate requesting all of my money back. I'll try to keep you guys updated.

That definitely sounds like a very huge disaster of a problem. I'd be curious to find out what caused it. I wonder if a car with a few years and miles on it is more likely to have any big issues already taken care of by the previous owner.

I read on Wikipedia that the 5.0L tau engine has a compression ratio: 11.5:1.

I’ve got the 3.3 L twin turbo lambda engine. As best I can tell it has a 10:1 compression ratio. I read elsewhere that a tubocharged Subaru Impreza has an 8:1 compression ratio.

The owner’s manual says 87 octane or higher is recommended for my engine. That surprises me since it is turbocharged, and having twin turbochargers, I suspect the manifold pressure can be pretty high.

For the 5.0 L tau engine, 87 or higher is recommended, but for “improved vehicle performance”, 91 or higher octane is recommended.

I know almost nothing about car engines, but for airplane engines, the high output engines (> 200 HP or so) use 100 octane fuel. The reason I was taught is that the higher octane fuel burns more smoothly, and pushes the piston so to speak rather than banging against it (detonation). My understanding in aircraft engines is that the compression ratio is typically 10 or 10.5:1 with normally aspirated engines and 8:1 with turbo engines. The reason for the lower compression ratio with turbocharged engines is with the higher manifold pressure and intake air temperature (though I understand the lambda engine has an intercooler) is to reduce the chance of detonation.

So, that being said, since higher octane reduces detonation/knock, and turbocharged engine are more susceptible to detonation due to higher combustion chamber pressures and temperatures, I would have expected the turbo-charged engine to be more susceptible to knock and to require higher octane fuel.

From reading this webpage comparing GDI to MPI, I take away that GDI is more efficient, allowing much lower fuel to air ratio at idle and routine driving speeds, and also allows for a higher compression ratio: Technology:Gasoline Direct Injection Engine

I drove both engines before buying. I did ask here about 3.3T vs. 5.0. I actually preferred the low end of the 3.3T, which is most of my driving in the city. Professional reviewers couldn’t tell much difference either. I see the 0-60 is the same at 5.3 seconds for both engines, though the 5.0 is faster for the quarter mile. I couldn’t tell a difference in acceleration while taking my test drives, but I wasn’t flooring it for a quarter mile. The 3.3L turbo weighs about 300 pounds less than the V8, and I could tell the difference in the front end while driving on a curvy road.

I was going to go with the 5.0 based on advice given here. I brought a 5.0 home for a week while waiting for a 3.3T in my preferred color to come in from being a demo. IO decided to get the 5.0 after driving it for the week, figuring the normally aspirated engine would be more reliable. However, it sold sight-unseen while I had it. I’m happy with the 3.3T and I’ve got the 10 year powertrain warranty. I’ll likely be using the Genesis dealer long-term for routine maintenance, so the dealership’s lifetime powertrain warranty will kick in after 10 years.

I'm guessing they say 87-octane is allowed because the ECU can retard timing and reduce boost to compensate for the lower octane at reduced performance.

GDI is much more efficient, produces more power and better fuel economy. However, it also has some serious drawbacks in that the placement of the fuel injectors in the combustion chamber means there's no longer fuel spraying the back of the intake valves, which in an MPI engine, kept them clean. As blowby and crankcase vapors are recirculated back through the intake through the PCV, the solids can accumulate on the backs of the valves, causing them to reduce airflow and valve sealing. If it gets bad enough, it can cause performance degradation and even driveability issues. The Germans had some serious problems in the early days of GDI. Walnut shell blasting is a common method used to clean carboned-up intake valves. Lexus and GM V8s have both GDI and MPI injectors to keep the valves clean. Another drawback is just the extra complication and cost of parts. MPI just had a single in-tank fuel pump pressurizing fuel to 40-60psi. GDI has a low pressure in-tank pump, and a pair of High Pressure fuel pumps (on V-engines) that pressurizes fuel to around 2900psi. The HPFPs are quite expensive at $300-1000 each depending on the car, and the GDI injectors cost a bit more than their MPI counterparts as well. GDI injectors themselves also fail at a higher rate as they tend to clog more easily, being in the combustion chamber. Pretty much every car made within the last decade is GDI, so there's not really any avoiding it.

3.3T might actually be more fun for hobbyists as it has tuning potential. I'm mainly looking at the V8 as this would replace my wife's daily, and she isn't interested in more power than the V8 has. The car wouldn't have warranty for very long (the 10yr powertrain doesn't transfer), so lack of turbos is less to worry about and easier to work on (I assume any turbo service is engine-out due to location).

 

[jcgraff]

Thanks for the great information about GDI vs. MPI.

My aircraft engine is direct injection. Aviation fuel still has lead in it to add protection from detonation, even though the fuel is 100 octane. Lead likes to deposit on the intake valves, even though there is an agent added to the fuel to try to solubilize it, at low engine temperatures that doesn’t work. I’ve had a sticking exhaust valve from lead-compounds (they were sent for spectroscopy) at start up which led the sticking valve to strike the top of the piston, but fortunately did only minimal damage (replaced minimally bent push rod). When an intake valve sticks in flight it can be catastrophic as it makes the whole side of the engine not breathe correctly/changes fuel air mixture due to the design of the engine.

So, given the issues with deposits on GDI engines, I am going to limit myself to TopTier gas stations as the Genesis manual recommends to reduce deposits. Many manufacturers do now. Was reading last night a Consumer Reports article that says it is worth it. AAA did independent testing and found after 4,000 miles 19 times less intake valve deposits by weight with TopTier vs. non-TopTier fuel. I suppose you could add the same fuel additive package TopTier uses. Wonder if it is cheaper to just pay an average of 3 cents per gallon at the pump and have it in the tank all the time rather than adding it every so often.

 

[GnatGoSplat]

I can imagine how a sticking valve could be catastrophic in an aircraft! What kind of aircraft and engine?

I've seen the articles about TopTier fuel, it sounds like a must-have for GDI engines. Fortunately, there's one very near my house. Interesting to hear it's actually mentioned in the Genesis manual. That definitely reinforces my belief that it's must-have. I'm guessing synthetic motor oil is also required by the manual, but whether it is or not, I consider it a must-have for GDI engines as it reduces solids in the PCV vapors. I've read there's a newer standard, ILSAC GF-6A, which is supposed to be even better for turbocharged GDI engines.

 

[RSpectnewbie]

If you have concerns about a GDI engine, install an oil catch can on the PCV line. That is the main source of oil into the intake, it is easily removable if you have to take the car in for service. Normally gasoline detergents would wash the carbon off the back of the vale, bit it is just as viable to try eliminate as much of it getting onto the valve stems as possible.
Buildup seemed to be more of an issue with Audi/VW from the research I did. But I put an OCC on my '13 mostly for peace of mind.
I also use full synthetic oil as well.

 

[jcgraff]

I can imagine how a sticking valve could be catastrophic in an aircraft! What kind of aircraft and engine?

I've seen the articles about TopTier fuel, it sounds like a must-have for GDI engines. Fortunately, there's one very near my house. Interesting to hear it's actually mentioned in the Genesis manual. That definitely reinforces my belief that it's must-have. I'm guessing synthetic motor oil is also required by the manual, but whether it is or not, I consider it a must-have for GDI engines as it reduces solids in the PCV vapors. I've read there's a newer standard, ILSAC GF-6A, which is supposed to be even better for turbocharged GDI engines.

This happened in my Beechcraft Bonanza powered by a Continental IO-550 engine. 6 cylinder, normally aspirated, 300 HP engine.

"Morning sickness" (sticking valve) most often happens with a cold engine at startup. It is uncommon on continentals, but relatively common on Lycomings. Different engine design. Lycomings have sodium filled valve stems to help with heat dispersion and Continentals are solid, but not sure that is the design difference that is responsible for Lycomings having it more often.

The last 20 years there has been a trend to run the engines on the lean side of stoichiometric fuel/air mixtures for better efficiency and lower cylinder pressures and engine temperatures. Our engines don't even automatically regulate air/fuel mixture! Even the new ones! It is suspected that my temperatures were cool enough that the lead scavenger wasn't able to work to combine with the lead in the fuel within the combustion chamber and go out with the exhaust, and got deposited on the valve stem, so that the valve could not seat properly.

In flight, it is indeed catastrophic with severe, if not total loss of engine power. You might think it would only affect one cylinder, but given the design of the engine, it makes all the cylinders on one side not breathe properly and maybe not produce any power, and could affect the other cylinders, to a lesser extent. Also, the valve could get broken and chewed up in the combustion chamber and bound around. Not a good thing.

Exhaust valves in aircraft engines are highly stressed and the combustion chamber is routinely checked at annual inspection or more frequently for color changes indicating they are not fully seating and at risk of failure. We watch EGT patterns of each cylinder from recordings of the engine monitor for a pattern of temperature undulation that is seen 25 or so hours before failure.

Another interesting thing is that smallaircraft engines are designs mostly from 80 years ago. They are "loose" engines and have a lot of blowby. Full synthetic oil has caused big problems in aircraft. Regular oil is better at solubulizing the products of combustion that get into the oil so they do not leave deposits and trigger bigger problems. I use multiweight non-synthetic oil, but partial synthetics of 25-50% are available. The benefit of synthetics is that you don't have to change oil as often, but in an airplane, we need to change the oil every 25-30 hours anyway to get rid of all the products of combustion before the oil becomes saturated. I know this stuff from extensive discussions with a petroleum engineer that specializes in aviation lubricants.

I wonder what oil the Genesis dealer will use for my G90, hopefully ILSAC GF-6A for my 3.3 L turbo V6. I see the manual recommends Quaker State, but that's all about payoffs for endorsements. I've got 3 years of free scheduled maintenance. The twin turbo V6 calls for oil changes every 6,000 miles. I see the V8 is only every 7,500. My wife's Honda Odyssey gets synthetic at the dealer and they say it is pointless to do it more often than every 10,000 miles. Car engines are a lot different than airplanes! There is so much liability in airplanes and so little demand compared to car engines, there is little motivation to change.

 

[MG8]

SOLID!!!!

 

[Ann L.]

Got to throw some shade on all the great comments. I purchased a new G90 Ultimate 5.0 AWD new on September 28, 2020. I returned it to the dealership for noise and vibration issues on October 2, 2020. They had it for 31 "workdays days" (meaning the days the service was opened). They replaced the front AWD transmission, the left rear tire, the left front wheel bearing and battery. I took it home and drove it for about 1800 miles.
On December 25, 2020, after hard acceleration, the engine went into a "limp" mode. No RPM over 2,000, max speed 50 MPH and looses power ging uphill, now power steering. I gently drove it to the dealership where it has remained since Dec. 26. Initially, the Service Manager was calling every other day with updates and that ended last week with no calls. They have been working with Genesis Technical since its return to the dealership with zero success at identifying the problem.
The car has been in the shop for 62 days and I've had the "opportunity to drive it for about 57 days since I've owned it.
To me, this is completely unacceptable. This is an $80,000 car with a myriad of problems and the Dealership nor Genesis Technical Engineers don't have any clue how to fix it. Fortunately, in NC where I live, there are very strong Lemon Laws that address situations like mine. I have filed a Lemon Law complaint thru a local attorney to Genesis Corporate requesting all of my money back. I'll try to keep you guys updated.

Arizona has a lemon law, but it does not apply to leases as the person leasing is considered the 2nd owner and the dealership the first owner. We had a leasor here with 23 repairs and Genesis refused to take the vehicle back due to Arizona lemon law not covering leased vehicles. What is also happening is Genesis is now requesting Hyundai dealerships separate their Genesis with brick and mortar and separate service department. In Phoenix one of the local Hyundai dealerships just dropped Genesis line as they will not comply. There are not enough vehicles sold to justify Genesis requirements. My lease is up in 2 months, and I will not get another Genesis due to their inability to follow through with the commitments they made upon leasing the vehicle 3 years ago. Also, my insurance agent advised me that Genesis auto insurance is much higher than Mercedes.