[Techy]

Yes, but not at first. The first problem was the heater wasn't working properly. Then the engine started stuttering. Check engine light eventually come on after the first few times it stuttered. Found there was NO engine coolant so filled it up, drove around the block and it was below min. again. Repeated that a few times as it wasn't holding coolant and eventually the over temp light came on. Wasn't holding coolant while running but was when it wasn't being driven (i.e. no leaks on the driveway). Couldn't drive it after that. That over temp light would go on when you started the engine cold. Had it towed to dealer last week.

Yup, the coolant loss and overheating is what caused the head gasket issue. I hope the cylinder head is OK but again, that would be covered by warranty. The heater issue would be directly related.
The overheating was caused by the heat exchanger in the catalytic converter and that is where your coolant was going.
If the dealer does not replace that expensive catalytic converter with heat exchanger integrated in it, your issue will not be solved.
Several people on this forum have bypassed the heat exchanger with excellent results - quick and very inexpensive repair.

 

[FlNiro]

Oh Techy, you made the light bulb go off in my head. I was thinking a bad head gasket led to the coolant loss like the old GM diesel issue. My old Chevy school bus (little bus based on the vans) were notorious for blowing head gaskets I didn't even think about the losing coolant issue from the heat exchanger. Your the man LOL. I guess the moral of the story for us Niro people is don't drive the car if your losing coolant and to keep an eye on your coolant.

 

[Relocated Vermonter]

Oh Techy, you made the light bulb go off in my head. I was thinking a bad head gasket led to the coolant loss like the old GM diesel issue. My old Chevy school bus (little bus based on the vans) were notorious for blowing head gaskets I didn't even think about the losing coolant issue from the heat exchanger. Your the man LOL. I guess the moral of the story for us Niro people is don't drive the car if your losing coolant and to keep an eye on your coolant.

But shouldn't there be some warning light or check engine light that goes off when it gets below min? And, yes, I will DEFINITELY keep an eye on it from now on! I get my oil changed regularly and if it were low then, it would've shown up. So the problem happened in the month or so since then.

 

[Techy]

But shouldn't there be some warning light or check engine light that goes off when it gets below min? And, yes, I will DEFINITELY keep an eye on it from now on! I get my oil changed regularly and if it were low then, it would've shown up. So the problem happened in the month or so since then.

No there is no warning light on the Niro for low coolant level.
I am planning to sell my 2020 to my daughter when I get my 2023.
I am seriously considering bypassing the heat exchanger before she gets the car because she will not watch the coolant level or notice warning signs that something is wrong.

 

[atc98092]

But shouldn't there be some warning light or check engine light that goes off when it gets below min?

No, there's no fluid level warning for the coolant. very few cars monitor much of any fluid levels. I believe there are some that watch brake fluid level and sometimes engine oil level. But mostly it's up to the driver to check levels on occasion.

 

[Relocated Vermonter]

What are the warning signs? And, even if I notice the coolant level going down, doesn't that mean there is still a problem that needs to be fixed? Or is the idea to fix that problem before it blows the gasket?

 

[Techy]

What are the warning signs? And, even if I notice the coolant level going down, doesn't that mean there is still a problem that needs to be fixed? Or is the idea to fix that problem before it blows the gasket?

Yes, if you notice the coolant level dropping or completely gone and no visible external leak than the likely culprit is the heat exchanger in the catalytic converter. The exhaust system burns up the coolant and you might have noticed a puff of white smoke from the tail pipe. Most people do not see the puff of smoke.
Like I said, if the dealer does not replace the converter, the problem is likely not fixed.

 

[Relocated Vermonter]

Yes, if you notice the coolant level dropping or completely gone and no visible external leak than the likely culprit is the heat exchanger in the catalytic converter. The exhaust system burns up the coolant and you might have noticed a puff of white smoke from the tail pipe. Most people do not see the puff of smoke.
Like I said, if the dealer does not replace the converter, the problem is likely not fixed.

Thanks for your help with this. Three weeks later, the repair work was done and covered under warranty. They had to replace the EGR cooler. My husband is concerned that there may be other engine damage from this whole incident. Is this likely and how would I know if there is other engine damage?

 

[Techy]

Thanks for your help with this. Three weeks later, the repair work was done and covered under warranty. They had to replace the EGR cooler. My husband is concerned that there may be other engine damage from this whole incident. Is this likely and how would I know if there is other engine damage?

If the coolant stays in the reservoir and the engine seems to run fine, then assume everything is OK.
I don't know what an EGR cooler is. Doubt that is what was replaced but as long as it is repaired, who cares.

 

[Relocated Vermonter]

If the coolant stays in the reservoir and the engine seems to run fine, then assume everything is OK.
I don't know what an EGR cooler is. Doubt that is what was replaced but as long as it is repaired, who cares.

Well, Techy, you were spot on. The check engine light went on 80 miles after I picked it up "fixed" from the dealer. Brought it back down and, hey, guess what? It needs a new catalytic converter. Sigh (The EGR cooler is the heat exchanger, BTW).

 

[Techy]

Well, Techy, you were spot on. The check engine light went on 80 miles after I picked it up "fixed" from the dealer. Brought it back down and, hey, guess what? It needs a new catalytic converter. Sigh (The EGR cooler is the heat exchanger, BTW).

There was nothing wrong with the EGR cooler and I'm not sure what it's purpose is.
As long as they are covering all this stuff under warranty, let them at it!

 

[Matt]

Yes, but not at first. The first problem was the heater wasn't working properly. Then the engine started stuttering. Check engine light eventually come on after the first few times it stuttered. Found there was NO engine coolant so filled it up, drove around the block and it was below min. again. Repeated that a few times as it wasn't holding coolant and eventually the over temp light came on. Wasn't holding coolant while running but was when it wasn't being driven (i.e. no leaks on the driveway). Couldn't drive it after that. That over temp light would go on when you started the engine cold. Had it towed to dealer last week.

I just had my 2017 with 168k miles towed to the dealer for loose of coolant - no overheat happened but the dealer said if it is a blown head gasket that they do not replace them because they can't warranty the work. Was quoted an engine replacement at $10k....

 

[Techy]

I just had my 2017 with 168k miles towed to the dealer for loose of coolant - no overheat happened but the dealer said if it is a blown head gasket that they do not replace them because they can't warranty the work. Was quoted an engine replacement at $10k....

It is likely not a blown head gasket but rather the heat exchanger in the catalytic converter. That is likely not covered under warranty either but at least it only costs around $2,000
There is no reason whey they cannot replace a head gasket or even another repair shop can do that and for way less than $10,000
Take it to a general repair shop that you trust and get them to bypass the heat exchanger as mentioned in this thread.

 

[Dovidan]

Matt: I hope your 1st 168K were trouble free as a number of owners have reported here. Sorry to hear about the coolant issue which a few others have reported, most with far fewer miles. Unless you drove a long distance with no coolant, this certainly should not require a new engine. Techy gives great advice.
Please keep us posted on how this plays out for you.

 

[Dovidan]

@ bigmike4899K : your last post was 2 months ago. In it you said your second head gasket went October 31, 2020.
Why did you almost 3 yrs to post this.
What is the latest on your Niro or have you moved onto another car?

 

[Matt]

It is likely not a blown head gasket but rather the heat exchanger in the catalytic converter. That is likely not covered under warranty either but at least it only costs around $2,000
There is no reason whey they cannot replace a head gasket or even another repair shop can do that and for way less than $10,000
Take it to a general repair shop that you trust and get them to bypass the heat exchanger as mentioned in this thread.

Good advice. They said they won't do the head because to they have no clearance for machining. The head was confirmed fail between water jacket and cylinder. Local shop quoted $2500 so we will probably go that route.