CX-9 2.5T Engine Replacement

It seems (at least from this thread) that owners reporting these issues all have 2016 MYs. Is that correct? I'd be interested to learn when the P/N was superseded.

I can't figure out from the online parts catalog when the number changed. I think you'd have to call a dealer parts department and get a friendly parts guy to dig through the system to get that info.

The pistons and rings have not changed since 2016. Whatever is causing the low compression problem that has popped up a few times hasn't resulted in any changes there.
 
It seems (at least from this thread) that owners reporting these issues all have 2016 MYs. Is that correct? I'd be interested to learn when the P/N was superseded.
Mine was a 2018. Another member’s was a 2019.
 
Mine was a 2018. Another member’s was a 2019.

That's why I was speculating perhaps in the 2020 MY when they added some more torque and "retuned" it, it was a quiet excuse to perhaps make the subtle change in the block and wherever else it needed it, but who knows.

If the OP could get back to us and tell us his model year, just for reference.
 
What year is your 2nd gen CX-9? I kind of wonder if they made any minor un-publicized fixes when they "retuned" the engine for the 2020 model and gave it a little more torque, hoping they did, but maybe they didn't.

Another user (with a 2nd gen cx-9 2.5T) also had an engine replaced, mchu123:

Here's another user (with a 2nd gen cx-9 2.5T) SaltyGoat who also had a cracked engine :

As the 2nd gen ages with the new 2.5T, it seems like quite a few cracked engine block cases are popping up. Mazda needs to look into this, especially since they plan to use this engine in virtually their whole lineup. That's a lot of potential engines they may need to replace in the future.
My CX-9 is a 2017

I should look on my paperwork to send what the part number for the block is. Wonder if it’s updated.
 
I'm sure Mazda already knows exactly how many engines they've replaced under warranty. The fact that Mazda's tech line recommended a compression test when presented with the symptoms is not a good sign. Still, there's about 5-10 posts on here, which isn't a huge number (yet?).

It appears that the part number for the short block changed, but I have no idea what is different between the two versions.

You all should go over to the Mustang6g forum and see how many 2.3L Ecoboost engines went belly up (although about half of them were stupid people flashing the PCM with some yahoo who thinks he can tune map an engine in 1 hour on a dyno...).

Then there's the 5.0...oh boy it's actually worse and that's an NA engine, not TDI pushing big torque from a small displacement. I wonder if some of these failures are LSPI related.
 
That's why I was speculating perhaps in the 2020 MY when they added some more torque and "retuned" it, it was a quiet excuse to perhaps make the subtle change in the block and wherever else it needed it, but who knows.

If the OP could get back to us and tell us his model year, just for reference.
According to Mazda, it's still 250 HP / 320 ft-lbs...:https://www.mazdausa.com/vehicles/2020-cx-9/compare-vehicle-specs-and-trims

As far as I know there is no change the overall output of the engine. However it is normal for them to change things year to year as issues are discovered. And perhaps there is some legitimacy to the old adage "never buy a first year model, no matter who makes it"?

The first and second years have the highest rates of issues typically no matter what brand, including Lexus (aka Toyota's luxury division), the most reliable brand on the planet in terms of reported issues.

For example Subaru had a tuning issue with the first half of the 2015 my WRX's, they were cracking pistons and replacing engines left and right until they figured it out. For those affected that did not already have catastrophic mechanical damage, they offered a free re-flash of the PCM to avoid the issue.

Anyone know if Mazda has any TSB's on a similar issue with those years?
 
According to Mazda, it's still 250 HP / 320 ft-lbs...:https://www.mazdausa.com/vehicles/2020-cx-9/compare-vehicle-specs-and-trims

As far as I know there is no change the overall output of the engine. However it is normal for them to change things year to year as issues are discovered. And perhaps there is some legitimacy to the old adage "never buy a first year model, no matter who makes it"?

The first and second years have the highest rates of issues typically no matter what brand, including Lexus (aka Toyota's luxury division), the most reliable brand on the planet in terms of reported issues.

For example Subaru had a tuning issue with the first half of the 2015 my WRX's, they were cracking pistons and replacing engines left and right until they figured it out. For those affected that did not already have catastrophic mechanical damage, they offered a free re-flash of the PCM to avoid the issue.

Anyone know if Mazda has any TSB's on a similar issue with those years?



The 2019 CX-9 had a specification of 250 HP/ 310 lbs ft.


When they released the 2020 CX-9 they had the press release on the slight power bump for the torque (gained +10, as I stated, and as posted on Mazda's site), I'd imagine it was slightly retuned, and who knows if they made any minor changes as they became aware of the cracked engine blocks:

https://news.mazdausa.com/vehicles-2020-Mazda-CX-9 :

New off-road traction assist, increased maximum torque from the turbocharged engine highlight many performance enhancements

Minimal changes, but non the less, they did something to the engine from MY 2019 to 2020(goes for the CX-5 as well when they added 10+ more lbs ft of torque). 310 lb ft to 320 lb ft in the 2020.

Everything still stands as per my original post, if it's not clear, the 2019 is 250 hp/310 lbs ft, while the 2020 has some "updates" and is posted as 250 hp/320 lbs ft, go back and check, I said MY 2020, and you posted MY 2020, ;)
 
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From a Facebook CX-9 group about cracked heads:

service manager at the dealership I used to work at said they put green locktite on the bolts that hold the exhaust manifold together and the heat causes it to expand and contract and over time ends up cracking the head we had 3 CX9’s that came in a week apart all 3 got new engines put in.

Any ideas how to prevent this issue?
 
Green??? "LOCTITE® Green Threadlocker is recommended for locking preassembled fasteners, e.g. electrical connectors and set screws. The product is categorized as medium-to-high-strength for wicking. It is also available in a liquid form, cures in 24 hours and can be removed with heat and hand tools."
https://www.henkel-adhesives.com/us...ts/blog/difference-between-threadlockers.html


Parts must be allowed to move with thermal expansion. If the parts aren't given a place to move, they'll find one, and it might be expensive. If mainly the manifolds that dealer fixed were cracking, then they did something wrong.
 
Parts must be allowed to move with thermal expansion. If the parts aren't given a place to move, they'll find one, and it might be expensive. If mainly the manifolds that dealer fixed were cracking, then they did something wrong.
Who is "they" that did something wrong -- the dealer or Mazda, or both?
 
I have a 2016 Mazda CX-9 with 115,000 miles. Just the other day I felt the car starting to misfire and jerking and then noticed the temperature needle moving up to about 250 degrees but did not hit the red area or give me a check engine light. I let the engine cool down and checked my radiator reservoir and it was empty. I bought the Asian Coolant for Mazda and filled the reservoir. I drove it a little and it started going to about 200 to 210. So I stopped. I could not see any coolant leaks from the bottom of the car. I ordered a thermostat and replaced it. It ran fine for a week and then started doing it again.

I took it to the dealer they said that there was coolant on the backside of the engine probably when I replaced the thermostat. They cleaned it off and told me to come back next week. I brought it back the next day because it was getting hot again. They kept the car and called me back the next day and said they notice a leak on the back of the engine and that they need to take the head off and send it to get inspected. They called me yesterday and said the head was good but they did see coolant in #2 and #3 cylinders and suggested I replace the entire engine! Cost is $7500. So they don't know where the leak is coming from and their solution is to replace the engine and that should fix it. I would certainly hope so. Have anyone encountered a similar problem?
 
Considering that Mazda is now the #1 brand in reliability on Consumer Reports, these engine cases are surprising. There's no way that this is a common issue with these rankings. Especially since the 2.5T is now used across much of the lineup. And Mazda had the confidence in the engine to add it to almost every model after the CX-9.
 
The old CX-9 gets average reliability ratings from CR even with the water pump and PTU issues. Take that however you will.
 
The old CX-9 gets average reliability ratings from CR even with the water pump and PTU issues. Take that however you will.
That would qualify as "average". Most vehicles have issues. Right now, Toyota and Lexus who have been near or #1 for many years are having more issues than Mazda.

Everyone also knows that the 1st person to sign up to an online forum is the one with an issue. Is this an issue? Yes. But it's very rare at this point.
 
There are 12 posts on here from people who got new 2.5T engines at this point. There are about 30-40 people who needed new 3.5/3.7 V6's. I'd say the rarity of the two issues is about the same, given that the old generation is 6-14 years old at this point.
 
There are 12 posts on here from people who got new 2.5T engines at this point. There are about 30-40 people who needed new 3.5/3.7 V6's. I'd say the rarity of the two issues is about the same, given that the old generation is 6-14 years old at this point.
Let’s hope so, but it seems to be happening more frequently now. Plus, there was a head issue on the n/a 2.5’s that was wide spread.
 

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