2021 CX-9 Low coolant, does this year have the head defect?

[camaro322hp]

Hello all. 2021 with ~40k miles. Admittedly I haven't monitored the coolant level recently so I can't say how quickly this happened. I glanced at the overflow reservoir today and it is about an inch above the bottom of the reservoir, well below the L line (when cold). See attached image.

I read up on the issue with the cracked heads, but as I understand it, that only affected model years 2020 and prior. This vehicle is parked in a garage and I have seen no evidence of a leak on the ground.

Advice? I was planning on topping it off and monitoring it.

 

[hsdejong]

With the level way down below the "L" line it is possible that there is not enough coolant in the motor and radiator.

 

[camaro322hp]

With the level way down below the "L" line it is possible that there is not enough coolant in the motor and radiator.

Forgot to mention that the radiator is full.

Also, today I'm planning on climbing under the vehicle to look for evidence of leaks. Will post back with update.

 

[hsdejong]

Forgot to mention that the radiator is full.

Then the low coolant level in the overflow reservoir had (fortunately) no influence on the cooling of the engine.
But I do recommend topping up the overflow reservoir to prevent the coolant level in the engine from becoming insufficient.

 

[camaro322hp]

Got it up on the ramps and took a look at the oil filter / exhaust manifold area and don't see any telltale green stains on anything. I know the leak could be entirely internal, but given the evidence I have at the moment (2021, no visible leaks, no sweet smell) I think I'll just top it off and monitor. If it continues to drop I guess I'll have to get the dealer involved. Not looking forward to that since I'm sure I'll be charged a substantial fee just for them to look at it.

 

[N7turbo]

Take a sample from your next oil change and send it to Oil Analyzers.

 

[hsdejong]

Admittedly I haven't monitored the coolant level recently

Are you sure the level has dropped over time?
Could it be that the level was already that low from the moment you got the car?

 

[camaro322hp]

Are you sure the level has dropped over time?
Could it be that the level was already that low from the moment you got the car?

Good point. We bought the car new in 2021. It's unlikely that it was delivered from the dealer with low coolant, but I guess it is possible.

As far as maintenance, I have been doing oil changes when the car asked for them. I don't specifically recall checking the coolant level over the 3 years, but if I had to guess I'd say I glanced at the coolant once or twice during those oil changes.

Picked up a jug of FL22 so I will top it off and find out if it's indeed leaking.

Take a sample from your next oil change and send it to Oil Analyzers.

Good idea, will do.

 

[camaro322hp]

Take a sample from your next oil change and send it to Oil Analyzers.

Never done this before. Is Blackstone still the best place to do these?

 

[N7turbo]

Never done this before. Is Blackstone still the best place to do these?

I chose Oil Analyzers because their fuel dilution test is supposedly more accurate and that is important to me on this car. Whichever you choose, it's best to stay consistent.

 

[PTguy]

Check your coolant level in the plastic tank at consistent temperatures. It will rise and fall as the coolant in the engine temperature varies.

 

[hsdejong]

Fill the overflow reservoir when the engine is cold to the F line.
And like PTguy wrote: the level will change according the engine and coolant temperature.

 

[csb_1237]

I chose Oil Analyzers because their fuel dilution test is supposedly more accurate and that is important to me on this car. Whichever you choose, it's best to stay consistent.

If this is the same place that Amsoil recommends, then they are, for sure, the best. I used them many times (a long time ago) and was always very pleased with the results they provided!

 

[csb_1237]

Got it up on the ramps and took a look at the oil filter / exhaust manifold area and don't see any telltale green stains on anything. I know the leak could be entirely internal, but given the evidence I have at the moment (2021, no visible leaks, no sweet smell) I think I'll just top it off and monitor. If it continues to drop I guess I'll have to get the dealer involved. Not looking forward to that since I'm sure I'll be charged a substantial fee just for them to look at it.

2021 was still in the range of the head problem for the 2.5L T Skyactiv. Be sure to let the folks investigating a class action know if you, indeed, have the dreaded head failure. Mazda CX-9, CX-5 and Mazda6 Engine Coolant Leak - Class Action Investigation

 

[youri]

2021 was still in the range of the head problem for the 2.5L T Skyactiv. Be sure to let the folks investigating a class action know if you, indeed, have the dreaded head failure. Mazda CX-9, CX-5 and Mazda6 Engine Coolant Leak - Class Action Investigation

What is your source ? The TSB only covers up to 2020, which seems to indicate the new designed head was introduced in the production line after 9 June 2020.

https://static.nhtsa.gov/odi/tsbs/2023/MC-10232269-0001.pdf

 

[csb_1237]

What is your source ? The TSB only covers up to 2020, which seems to indicate the new designed head was introduced in the production line after 9 June 2020.

https://static.nhtsa.gov/odi/tsbs/2023/MC-10232269-0001.pdf

I could be mistaken, but I believe the TSB was updated. Let me check my archives and see if I can find it. I apologize if I have provided any false information, but what I remember is that some of the 2021 models had the (potentially) defective heads.

 

[camaro322hp]

Since topping off the coolant a couple months ago, the level hasn't changed at all. Every TSB I've found only includes VINs up to 2020. So I think I'm good.

 

[PTguy]

It is good to use a lab that includes a test for insolubles in the oil. The gasoline direct injection can cause some very fine soot that gets past the rings and into the engine. This soot is too small to be caught in the oil filter and is abrasive. The soot, if in significant quantities, will show in the test for insolubles. The only solutions are to use a good injector cleaner occasionally and to change the oil more frequently if the insolubles are high.