2016~2020 2016 GT Coolant Leak Rear of Engine

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2016 CX9 GT AWD
I'm in the dealership and they have just informed me that my 2016 has a coolant leak on the rear of the engine block.
They are calling into Mazda NA for authorization to dig deeper under drivetrain warranty.

I'm just under 60K miles. Mostly commuting about 40% interstate, 50% back roads and 10% stop and go.
I do like to mash the pedla when merging and passing. I'm a "spirited" driver.
But hoping this is nothing to serious and not a sign of things to come for 1st year turbos...(eek2)

I will update as I know more info.

Anyone else had a similar problem?
 
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2016 CX9 GT AWD
So I'm home with a 2017 CX5 loaner.
They are replacing the entire engine under warranty.
They said about a week to get the engine in and about a week for the repair.

They will know more about the cause when they pull the engine.
They only know it's leaking at the rear where there are no hoses, pumps, etc.
So gasket, head or block leak.
 
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sm1ke

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Thanks for posting about this issue. It seems strange that they're replacing the entire engine, but I've never experienced anything like this so I don't know if that's to be expected. Was the engine running poorly when the techs inspected it? Was the car at the dealership for routine maintenance or something else?

Hopefully this was a one-off occurrence and the engine replacement goes smoothly. Seems like a pretty painless warranty experience - that, at the very least, is a positive takeaway from this.
 
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2007 Mazda CX-9 Touring
How many miles did you have on the vehicle? please let us know what caused the leak if they give you that information.
 
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2016 CX9 GT AWD
The vehicle was in for an oil change and tire rotation. No known mechanical issues when I scheduled service.
The mechanic stated he smelled the characteristic smell of hot coolant and noticed the leak while doing the oil change.
Further inspection showed a leak from the "back" of the engine, from an area where there are no hoses, water pumps, etc.
So that would seem to indicate a failure of the head, block or the gasket.

I don't have the exact mileage but the service writer mentioned ~57K miles when I spoke with him.
They report that there was no noticeable loss of coolant. The reservoir was within normal limits for hot engine and the same dealer was the last to service and check fluids.
Current service interval is 4500 miles and the leak was either not present or not noticed at the time of the previous service which was also oil change and rotation.

At the time of service the vehicle was running perfectly, no lights, no codes, no hesitation, pulling strong, no overheating smells or hot coolant smells at any time while parked or in operation and no noticeable coolant leak while parked.
It sounds like instead of tearing into it and messing around with trying to determine what failed and why, they are replacing the entire engine.
Call it an over abundance of caution, doing the right thing or creating goodwill. The important part is that Mazda North America is stepping up to make it right.

Below is all speculation on my part...

I'm guessing that if they were to pull the engine, they'd have to determine if it was the gasket failing, then determine if the gasket failed, was any harm was done to the head/block? If so which is bad and which needs to be replaced?
Or they pull the engine and find the block or head cracked so now they have to order parts and still need to replace something.
So probably doing a clean swap of the engine makes the most sense from time, money and customer satisfaction standpoints.
Also, if this IS the first reported failure of this type, Mazda may want the engine for examination and testing to see what failed and why.
 
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sm1ke

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The vehicle was in for an oil change and tire rotation. No known mechanical issues when I scheduled service.
The mechanic stated he smelled the characteristic smell of hot coolant and noticed the leak while doing the oil change.
Further inspection showed a leak from the "back" of the engine, from an area where there are no hoses, water pumps, etc.
So that would seem to indicate a failure of the head, block or the gasket.

I don't have the exact mileage but the service writer mentioned ~57K miles when I spoke with him.
They report that there was no noticeable loss of coolant. The reservoir was within normal limits for hot engine and the same dealer was the last to service and check fluids.
Current service interval is 4500 miles and the leak was either not present or not noticed at the time of the previous service which was also oil change and rotation.

At the time of service the vehicle was running perfectly, no lights, no codes, no hesitation, pulling strong, no overheating smells or hot coolant smells at any time while parked or in operation and no noticeable coolant leak while parked.
It sounds like instead of tearing into it and messing around with trying to determine what failed and why, they are replacing the entire engine.
Call it an over abundance of caution, doing the right thing or creating goodwill. The important part is that Mazda North America is stepping up to make it right.

Below is all speculation on my part...

I'm guessing that if they were to pull the engine, they'd have to determine if it was the gasket failing, then determine if the gasket failed, was any harm was done to the head/block? If so which is bad and which needs to be replaced?
Or they pull the engine and find the block or head cracked so now they have to order parts and still need to replace something.
So probably doing a clean swap of the engine makes the most sense from time, money and customer satisfaction standpoints.
Also, if this IS the first reported failure of this type, Mazda may want the engine for examination and testing to see what failed and why.
Thanks, I appreciate the rundown. That's a good point about keeping the engine for further examination/testing. I know that as a customer, I'd be happier with a brand new engine than an engine rebuild (though I would accept either as a satisfactory resolution).
 
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2016 CX9 GT AWD
Not much of an update; I called the dealer today and they said the parts have all arrived.
They are putting it in the schedule this week with an elite master technician.

In the meantime, I have been flogging a nicely equipped 2017 CX5 loaner.
The 2.5NA isn't a bad mill in the CX5, but I miss my turbo.
 
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2016 CX9 GT AWD
Friday July 26th, one month after my initial visit to the dealership I received a call from the service manager saying my car was done and that they wanted to do a "long test drive, maybe 50 miles including some highway" and that I should be able to pick it up on Monday.

Monday morning I called and confirmed that it would be ready to pick up by noon. I turned in my loaner, paid for some other work (brakes) and took possession of the car. Less than 2 miles from the dealership I hear a sudden noise coming from under the engine area. I pull over and find the plastic engine shield under the engine has come loose at the front edge and is plowing/dragging across the ground.

I called the dealership and after being on hold for 10 minutes, the lower-level employee who answered just said to bring the car back. I asked them to put me through to the service manager, because I was concerned about the dragging shield making the problem worse/causing other damage. They tell me to bring the car back and they will take care of everything.

On the way back to the dealership, the scraping sound turns into a whomp, whomp, whomp sound and at one point my low tire pressure warning light comes on. I couldn't see any tire damage when I arrived at the dealership. I spoke with the service writer and told them they had better inspect for any tire damage. I have a $1200 set of Continental ExtremeContact DWS on the vehicle that are less than a year old. If a tire was damaged by the shield, they will have to either buy me a whole new set or contact Tire rack and order a shaved down tire to match the current tread depth.
The pressure light might have just been a coincidence, but I'd like them to check it out.

I left the car with them in disgust, reclaimed my loaner and contacted the GM of the dealership directly. They are working on getting the shield here and installed by tomorrow, no word yet on the tires, if it has been looked at and what the verdict is, which is worrying.

That said, it seemed to run fine for the total of 4 miles I drove it, not counting the shield noises. They were not able to provide any more detail about the nature of the problem, only that MNAO had requested return of the original engine.

I was so happy with the dealership in the beginning when they found the issue and promptly secured authorization to have the engine replaced under warranty. They also got the cracked infotainment screen authorized for a warranty repair. There response was great.

The subsequent experience has been far from good.
They provided no communication on the status of the repair; I received updates only when I reached out; I called once for an update and stopped by once to get my EZPass out of the car.

It's funny because they originally told me a week to get parts and a week to so the work and I laughed saying "it will be longer than that."
They obviously did not do any kind of test drive; I can't believe the shield came off after a 50 mile test drive, then fell off 2 miles after I leave the dealer.
It also points to the fact that the shield wasn't reinstalled correctly; less than confidence inspiring from a dealership that just put a new engine in.
 
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YCT

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2018 Mazda CX-9 Signature
Is it possible that the tire ran over the cover and had a screw lodged into the wire causing the sound? Would also explain the tpms light coming on. Sorry to hear that you are going through this, I am sure you are livid. Here's to hoping that the dealership does right by you and corrects everything once and for all.
 

sm1ke

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Sorry to hear about the recent experience. The TPMS light might have something to do with the plastic cover messing with the ABS sensor in the wheel well. Maybe the sensor got disconnected and that's what is causing the warning light to come on?

Any chance you snapped a pic of the loose cover piece?
 
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2016 CX9 GT AWD
I was thinking what YCT suggested, that the flapping engine shield somehow caused a puncture or gash in the tire.
Sorry, no pic of the shield hanging down. If you've ever been under the car, it is obvious what piece I'm referring to.
It runs from the front bumper to under the engine, a big, black plastic sheet or pan to smooth airflow under the front of the car.
If it's hanging down, it's quite obvious, visually and audibly.

The dealer called me yesterday around noon and said a new shield and clips had been installed and that they found a nail in one of the tires.
So it looks like the TPM light was due to the nail and just a shitty coincidence. They plugged the tire and even saved the nail for me.
It might be that the shield as it was scraping and bulldozing along the ground threw ever bit of road debris into the path of the tires.

In addition to the shield and tire being fixed, the service manager took it out for a 20 mile test drive to make sure it was running right.
When I arrived to pick up the car they had detailed it and wanted to put some gas in it to cover the test drive, but I told them it was OK I was more worried about the mechanical issues being sorted out than a gallon of gas.

I spoke with some service personnel and they confirmed that this was the 1st CX9 turbo that they had in for a coolant leak.
But they have had a couple of turbo CX5's with similar issues and engines replaced.
Considering the CX5 got the turbo plant AFTER the CX9, it looks like the 2.5 may not be so robust when turboed.
Take that into consideration before doing any mods seeking more ponies.
If you consider that the average CX 9 driver is not going to flog their 7 passenger vehicle hard, but at 1000lbs lighter, thousands cheaper and a younger buyer, the turbo CX5's might be getting ridden hard and put away wet more often.

The car otherwise seemed to run OK on the way home.
Having not driven it in awhile and considering it's a brand new engine, I'm following the original Mazda recommendations for the 1st 600 miles.
(Do not race the engine. Do not maintain one constant speed, either slow or fast, for a long period of time. Do not drive constantly at full-throttle or high engine rpm for extended periods of time, etc.)

BUT THEN TODAY...

On the way to work the oil light came on. It has NEVER come on before. As soon as I noticed it I pulled over and shut engine off.
I grabbed a napkin and popped the hood. The first thing I noticed is that the engine cover with Mazda logo that sits on top of the engine and over the oil fill/dipstick holes is loose and askew.
I pulled the dipstick and there appeared to be plenty of clean oil; I wiped it and stuck it back in.
I lift the engine cover, see the little ball-end fittings that pop into round mounts and re-align it and pop it back on securely.
I check the oil again after it sat about 30 seconds and there is oil up to the fill mark.

I'm 5 minutes from work so I start the engine, no oil light and drive slowly into work.
the oil light didn't come on the rest of the ride. I haven't called the dealer yet.
I'm going to go back out and check it cold before I call them.

I use to LOVE this engine and vehicle. I recommended the CX9 to friends and family, then the CX5 and 6 when they became available with the turbo.
Now I'm very leery of recommending it and until I get some more miles on the new engine, I feel like I'm driving a timebomb.
 
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2015 Mazda 3
It's been leaking green antifreeze onto my garage floor. I raised the CX-9 and took off the oil change door and there was green fluid all over. The reserve tank was empty so I filled it to the high mark - it didn't take that much to fill it though. However I'm pretty concerned.

I took it to the Mazda dealer where I bought it a few hours ago - they said they may have to replace the engine, which makes no sense to me. I'm just over the 5yr/60,000 mile powertrain warranty mileage limit at 64,500 (but only 3.5 years) - I'm praying Mazda is going to cover any repairs. This is my 3rd Mazda purchased new since 2015 - hoping they will do the right thing.
 
I believe I may have the same issue. I have a coolant leak as well and a shop told me that because the engine block is made of aluminum, the bolts that hold it together may have loosened causing the top part of the engine to pull away and causing the leak. They are estimating $2500-3000 for the repair because they have to pull apart the told of the engine block and possibly re-thread the bolts. I read above that the dealership is just doing an engine swap to address possibly this same issue. How much does an engine swap usually cost? If it's not much more than I rather just swap the engine and start fresh.
 

sm1ke

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I believe I may have the same issue. I have a coolant leak as well and a shop told me that because the engine block is made of aluminum, the bolts that hold it together may have loosened causing the top part of the engine to pull away and causing the leak. They are estimating $2500-3000 for the repair because they have to pull apart the told of the engine block and possibly re-thread the bolts. I read above that the dealership is just doing an engine swap to address possibly this same issue. How much does an engine swap usually cost? If it's not much more than I rather just swap the engine and start fresh.
You shouldn't have to worry about any of that unless you're out of warranty. Are you out of warranty? How many miles/km on your engine?
 
I am out of warranty, but as silly as it sounds I almost forgot I purchased a third party extended warranty when I bought the car used. Now I just have to pay 300 dollar deductible. Thank God!
 

sm1ke

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That's a big relief! I mean, its still $300, but at least it isn't $3000. Still, this is a bit concerning. I think this is three reported cases on the forum now, which really isn't that bad at all statistically, but it isn't representative of all 2.5T engines. Keep us posted with what happens with the dealership and what they decide to do (and if they can verify that their diagnosis is correct).
 
That's a big relief! I mean, its still $300, but at least it isn't $3000. Still, this is a bit concerning. I think this is three reported cases on the forum now, which really isn't that bad at all statistically, but it isn't representative of all 2.5T engines. Keep us posted with what happens with the dealership and what they decide to do (and if they can verify that their diagnosis is correct).
Ya it’s such a relief, I’m actually having the work done at a local trusted shop. Easier than dealing with the dealership. But will keep you posted.
 
Ya it’s such a relief, I’m actually having the work done at a local trusted shop. Easier than dealing with the dealership. But will keep you posted.
How many miles do you have on your CX-9?

Extremely small sample size, as sm1ke points out, but I wonder if this is a sign of things to come when people start to get around the 4yr/60K milestone.
 
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