5.0 Coolant Leak

[skipgen]

I was informed by my mechanic that I have a coolant leak that appears to be coming from underneath the intake manifold towards the rear of the engine. Anyone have an experience with this?

 

[jimmy buoy]

No personal experience, but there have been issues with newer 5.0 models where an O-Ring in that exact spot on a coolant pipe that goes to the transmission begins to leak. I think Hyundai has a service bulletin for the issue which involves taking the manifold, replacing the O-Ring with an improved one which seals everything again. You don't want to ignore since low coolant levels could cause an overheat and engine damage.

Here's a thread on this issue... (G90 issue, but the same 5.0 engine so who knows)

Genesis G90 2018 transmission issues.

 

[skipgen]

No personal experience, but there have been issues with newer 5.0 models where an O-Ring in that exact spot on a coolant pipe that goes to the transmission begins to leak. I think Hyundai has a service bulletin for the issue which involves taking the manifold, replacing the O-Ring with an improved one which seals everything again. You don't want to ignore since low coolant levels could cause an overheat and engine damage.

Here's a thread on this issue... (G90 issue, but the same 5.0 engine so who knows)

Genesis G90 2018 transmission issues.

Thanks.... I had found that thread after I posted. It's barely a dribble that they noticed when changing the oil - My coolant wasn't even low. I'll be keeping an eye on it. Doesn't look like that much of a pain in the ass to get to though.

 

[skipgen]

Update - it must not be much of a leak. I'm on my 4th day of operation (~30 mi. per day) and the coolant level as measured @ the reservoir hasn't budged... Took a moment to marvel at the remarkably engineered dipstick thingy. Pretty neat (Yes, I'm occasionally very easily entertained).

Kinda wonder if they overdid pressurizing the system...

 

[Kraig Wilkinson]

Update - it must not be much of a leak. I'm on my 4th day of operation (~30 mi. per day) and the coolant level as measured @ the reservoir hasn't budged... Took a moment to marvel at the remarkably engineered dipstick thingy. Pretty neat (Yes, I'm occasionally very easily entertained).

Kinda wonder if they overdid pressurizing the system...

Keep us posted. I am kind of curious how bad of a job it would be to replace. Thanks

 

[Kraig Wilkinson]

Update - it must not be much of a leak. I'm on my 4th day of operation (~30 mi. per day) and the coolant level as measured @ the reservoir hasn't budged... Took a moment to marvel at the remarkably engineered dipstick thingy. Pretty neat (Yes, I'm occasionally very easily entertained).

Kinda wonder if they overdid pressurizing the system...

How many miles do you have on your Genny?

 

[skipgen]

How many miles do you have on your Genny?

70K 1st owner put mostly highway miles on it. It was well taken care of - even the inside shows minimal wear & still smells new.

 

[Kraig Wilkinson]

70K 1st owner put mostly highway miles on it. It was well taken care of - even the inside shows minimal wear & still smells new.

Yeah 10-4 ! I was just curious, I am going to go under my car this weekend and check it all out.

 

[skipgen]

Keep us posted. I am kind of curious how bad of a job it would be to replace. Thanks

From the link to the TSB that was in the above thread, it looks like a straightforward job, not hard to access once the manifold is off. Hyundaipartsdeal.com has the 2 o-rings that were mentioned in stock - .53 each, then you need 8 intake gaskets - about $8 ea. Of course, labor would be the killer...

 

[skipgen]

Yeah 10-4 ! I was just curious, I am going to go under my car this weekend and check it all out.

If it's doing it, you'll see it between the engine & bellhousing.

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[Kraig Wilkinson]

If it's doing it, you'll see it between the engine & bellhousing.

Thanks skipgen, I appreciate your input and knowledge. It is freaking like 10 degrees here and the roads are all salted up! So I am going to pull all panels underneath and wipe her down!

 

[ntmehan]

Hey Kraig and Skip, did this ever go anywhere with you guys? My 5.0 has enough of a leak (appears to be at the rear of the engine but damn if I can get under it far enough to actually see anything else) that after I sat idling in the driveway for a bit after the A/C stopped cooling and I was trying to troubleshoot, my temp shot up and when I shut the car down it leaked a solid 6-8oz of fluid onto the garage floor. This happened again the next day after I pulled the front aero cover to try to diagnose the leak. All the while, the amount of fluid in the bottle doesn't seem to be changing, after cleaning up roughly 12oz from the floor in less than 2 days...

I limped it to the dealer while it was cool-ish outside this morning, monitoring coolant temp with my OBD reader (it got to 240F when I parked at the dealer) and they're in their second hour trying to diagnose. SA called to confirm second diag hour and said the tech had to pull the intake (so I assume they're checking this O-ring issue.) Almost seems like the system isn't pulling fluid in from the reservoir (which was over full, hot and cold prior to startup this morning, according to the goofy-ass dipstick) because it took forever to come above one bar on the gauge (like there wasn't much liquid in it to circulate and get a reading. If I'm dumping coolant on the ground, (and I'm sure there's air in the system) then why is the bottle still full...

On a semi-related note, does anybody know if we have electronically controlled thermostats?

 

[skipgen]

Mine never got that bad... I may have had to add a quart of coolant since December. Now that it is warm, I haven't had to add a drop. I'm beginning to believe that the mechanic way over pressurized my system and the rubber washer in question has managed to reseat itself. It is something that I keep an eye on though. When the mechanic showed it to me, it did run down the back of the engine. I've never seen coolant leak onto the driveway anytime afterwards.

I haven't had any odd behavior during warm up. Comes up from cold gradually and then stays parked one meter segment under halfway. Just like it's always done.

I'm sure that the coolant flow to the trans warmer is electronically controlled - wouldn't make sense for it not to be.

 

[ntmehan]

Yeah, I'm assuming it actually functions as a cooler as well, if the fluid ever gets hot enough to need it.

For anyone else looking for warning signs, go with your gut. I started smelling coolant (I am admittedly very sensitive to that smell, as I've been told in the past that others can't smell coolant when I can) a few weeks ago (but it had just gotten consistently hot out) and began checking coolant levels. I searched the forums and there are threads (mostly for G70 and Stinger with the 3.3TT, but still) about smelling coolant after spirited runs and hot days, so I assumed I was being oversensitive and it wasn't a problem, especially with coolant levels remaining the same.

Last Tuesday after a 50ish mile drive, mostly highway, it was 85F and humid as hell after dark, when the air started blowing warm/moist. Parked in the garage and the cooling fan stayed on after key-off. Drove it the next day, and everything seemed fine. Drove it again Friday to run errands, and on they way home, the A/C (95F out that day) cut out periodically for about 5 minutes and then kicked off and didn't come back on for the last 2 minutes of the drive home. I sat in the driveway trying to diagnose, and that's when the coolant temp gauge finally indicated that something was off. It quickly went into the overheat zone blinking the red bars, popped up a BlueLink message on the Nav screen and illuminated the check engine light. OBD reader said coolant temps were around 230-235F. Oddly, I don't think the fan kept running on key-off... After all this happened, I backed it into the garage and when I shut it off, sometime over the next hour is when it leaked fluid onto the floor.

 

[Kraig Wilkinson]

Yeah, I'm assuming it actually functions as a cooler as well, if the fluid ever gets hot enough to need it.

For anyone else looking for warning signs, go with your gut. I started smelling coolant (I am admittedly very sensitive to that smell, as I've been told in the past that others can't smell coolant when I can) a few weeks ago (but it had just gotten consistently hot out) and began checking coolant levels. I searched the forums and there are threads (mostly for G70 and Stinger with the 3.3TT, but still) about smelling coolant after spirited runs and hot days, so I assumed I was being oversensitive and it wasn't a problem, especially with coolant levels remaining the same.

Last Tuesday after a 50ish mile drive, mostly highway, it was 85F and humid as hell after dark, when the air started blowing warm/moist. Parked in the garage and the cooling fan stayed on after key-off. Drove it the next day, and everything seemed fine. Drove it again Friday to run errands, and on they way home, the A/C (95F out that day) cut out periodically for about 5 minutes and then kicked off and didn't come back on for the last 2 minutes of the drive home. I sat in the driveway trying to diagnose, and that's when the coolant temp gauge finally indicated that something was off. It quickly went into the overheat zone blinking the red bars, popped up a BlueLink message on the Nav screen and illuminated the check engine light. OBD reader said coolant temps were around 230-235F. Oddly, I don't think the fan kept running on key-off... After all this happened, I backed it into the garage and when I shut it off, sometime over the next hour is when it leaked fluid onto the floor.

If the leak is substantial it wont pull coolant from reservoir. It will just suck air from the leaking o ring or whatever is leaking. I would fill it up from radiator cap if you run into that problem again. I would imagine the fully aluminum engine dont like those high temps. And I agree the dipstick in coolant reservoir is kind of wierd.

 

[ntmehan]

If the leak is substantial it wont pull coolant from reservoir. It will just suck air from the leaking o ring or whatever is leaking. I would fill it up from radiator cap if you run into that problem again. I would imagine the fully aluminum engine dont like those high temps. And I agree the dipstick in coolant reservoir is kind of wierd.

That makes sense. Part that blows my mind is that it seems the cluster has a delay in displaying the coolant temp spike. I think the other day the AC was kicking off to lower coolant temps when they passed 205-210F, but the coolant temp gauge didn't go up (and even then only 2 bars, to one above the middle of the gauge) until it remained in the 220-225F range for a minute or so. (Probably 30F above normal?) A minute or so later when it shot up to the overheat range my OBD reader was only actually reporting 230-240F. (Even though this morning 240F at the dealer still only showed one bar above half.) Seems that the second bar during warm up doesn't show up until it's in the 120-130ish range, so the overall range that can be indicated is between one bar (cold) and the two final bars blinking together in the red zone (overheat) is 130-240? So each bar is slightly under 10F but at 30-50 over normal, there was no indicated problem...

All that to say, if your car indicates a problem, it's probably not a sensor blip (I guess the cluster is smoothing for sensor and communication issues...?), it's probably actually a problem that needs to be dealt with immediately.

 

[Kraig Wilkinson]

That makes sense. Part that blows my mind is that it seems the cluster has a delay in displaying the coolant temp spike. I think the other day the AC was kicking off to lower coolant temps when they passed 205-210F, but the coolant temp gauge didn't go up (and even then only 2 bars, to one above the middle of the gauge) until it remained in the 220-225F range for a minute or so. (Probably 30F above normal?) A minute or so later when it shot up to the overheat range my OBD reader was only actually reporting 230-240F. (Even though this morning 240F at the dealer still only showed one bar above half.) Seems that the second bar during warm up doesn't show up until it's in the 120-130ish range, so the overall range that can be indicated is between one bar (cold) and the two final bars blinking together in the red zone (overheat) is 130-240? So each bar is slightly under 10F but at 30-50 over normal, there was no indicated problem...

All that to say, if your car indicates a problem, it's probably not a sensor blip (I guess the cluster is smoothing for sensor and communication issues...?), it's probably actually a problem that needs to be dealt with immediately.

The temp sensor wont give correct readings if air is surrounding the sensor itself. Air in the system will surely cause those problems.

 

[joegr]

Also...
The temperature gauges on most cars are more like a temperature light than a gauge. They are programmed to quickly go to the middle and stay there without moving most of the time. When they finally do start to move up, the engine is already in trouble. I think that the carmakers' belief (or maybe experience) is that most drivers don't understand that it is normal for engine temperature to vary some based on conditions and engine load.

 

[ntmehan]

Well, it's the famous TSB 18-AT-017-1, ATF warmer connection that's the culprit. At least that's what the dealer thinks, even though I'm the one that told them about the TSB. I'm out of warranty based on time, just within based on miles (I'm under 59000miles) and the dealer wants to charge me $520 plus tax to replace the 2 $6 o-rings.

Also, assume those were replaced when the short block was replaced two years ago... Unfortunately 5 months before the latest TSB and I assume part number revision... So if that's true the new (old part number) O-rings only lasted 17,000 miles. If they were new as of July 2018, I bet that coincides perfectly with all the G90s that had this issue...

 

[ntmehan]

After spending an entire week in the shop, I picked the car up at about 11a. Supposedly they had bled the system and road tested that morning to wrap up. I was about a mile down the road and knew something didn't seem right. Coolant temp on gauge actually dropped from 4 bars back to 2 while I sat idling at a stop light, then less than half a mile of light throttle down the road quickly came right up not normal op temp. I turned the heat on manually and was still getting cold air so I knew the heater core was airlocked. After getting my OBD reader from my wife and checking that temps seemed normal, I punched the car, only able to run up to 4500rpm or so in second and a little pull in 3rd before I was at risk of jail, but that quick burst immediately pushed air out of the heater core and the HVAC immediately blew hot. I punched in onto the interstate keeping RPMs high and watching coolent temps on my phone and everything seemed normal. Hoping they just didn't get a good bleed on the system I drove like a sane person about 10 minutes back home, parked in the driveway and an hour later had a ton of coolant on the garage floor once again.

At this point I'm pissed. If a thorough road test and pressure test were performed (as was stated on my receipt) There's no reason this issue would have represented so quickly. Taking more time out of my workday to run the car back to the dealer (at which point coolant temps got up to 255F) I told them they had 20 minutes to either figure out what happened or get me in a loaner because they had wasted enough of my time today. There's coolant in the valley just like before, so they're going to have to pull the intake again. Tried to tell me "All our loaners are out, sorry" to which I told them I used to sell cars, I know you can get approval to give me a used car to drive for a few days, so go ask whoever you need to ask. You had more than enough time (part arrival took a while, but they could have taken more time on Friday to properly ensure the issue was fixed before they called me so early in the day to come pick it up.) to ensure the repair was completed properly and successfully and at this point you've wasted 2hrs of my day trying to return something that wasn't fixed. It's obviously not going to be fixed today, which means it'll be out of service all weekend, and I'll be lucky (absolutely not holding my breath) to get it back Monday or Tuesday next week.

So they sent me home in a new (why?) Kona. Meanwhile, I don't know what else could be wrong to be leaking in the same place, so I assume they'll have to order o-rings again and be more careful on the install this time...?

Through all this, and a reason nobody should ever trust a dealer: My initial quote of $520 +tax within 24 hrs was lowered to $120ish according to the Service Manager's callback to confirm Hyundai Motor America's agreement to my payment assistance request. (That I had to ask the dealer to submit.) When I picked it up, I was actually only charged $59 and some change and my receipt noted HMA would cover 50% of warranty cost of replacement. So unlike medical charges that are quadrupled for insurance companies and far cheaper for actual people to pay themselves, apparently Hyundai dealers, charge the customer 4x what the equivalent warranty from HMA pays, and in my case Hyundai agreed to pay half of their already 1/4 price. And anybody who didn't know to question the charges would have just paid $570 to fix a small coolant leak however much of a struggle that was for them and never known that they could even submit an assistance request to corporate. It's so frustrating that they're such snakes. I'm not bitching for myself, $60 is more than reasonable for this fix (if it actually gets fixed this time) but 8x that is abhorrent highway robbery and I feel bad for people that get taken advantage of by it.

Also if I pick this up Monday, it will have been in the shop 52 days out of the 405 I'll have owned it. That's just over an 1/8th of my ownership. Not super excited... Still absolutely love the car, but my wife gets a new car next, and that'll probably be 2-3 years, so I'm in the Genny for 4-5 and I'm just not sure it's not going to be a money pit...