2021 CX-9 burning oil

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2021 CX-9 Sig
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2021 CX-5 GT
Yes, you have to check the VIN and see if your vehicle falls within the range:

2021 CX-9 (2.5T) with VINS lower than JM3TC******541071 (produced before September 14, 2021)

I switched from a 7500 mile oil change interval to a 5000 mile oil change interval. My oil level seems fine till about 5000 miles and drops after that.
 

ctbale

Member
Contributor
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2016.5 CX-5 Touring
A reminder that this thread is about a 2021 CX-9 burning oil. It is not an opportunity to claim that the Mazda manual is incorrect. Please keep this thread on topic and specific or it will be closed.

Thank you.
How is the discussion about how 5.1 qts and a filter looks on the dip stick, and when the low oil lite trips NOT relevant to oil burn issues? My point is if you put in 5.1 qts, and it's only gets it mid point between the holes, then the low oil light trips at the lower hole, that could explain away high oil consumption to an incorrect stick or bad info for max fill amount. Totally on subject.
 

Antoine

Administrator
How is the discussion about how 5.1 qts and a filter looks on the dip stick, and when the low oil lite trips NOT relevant to oil burn issues? My point is if you put in 5.1 qts, and it's only gets it mid point between the holes, then the low oil light trips at the lower hole, that could explain away high oil consumption to an incorrect stick or bad info for max fill amount. Totally on subject.
I was referring to what I had mentioned in my post, that this thread is not an opportunity to claim that the Mazda manual is incorrect. I was not specifically referring to your posts.

Unfortunately these oil-related threads have a tendency to turn into heated debates and or soapboxes which stray off the original poster's question/point/topic and thus become off topic.

Let's keep threads respectful to the original topic as well as on track and as helpful as possible, thanks once again.
 

ctbale

Member
Contributor
:
2016.5 CX-5 Touring
I was referring to what I had mentioned in my post, that this thread is not an opportunity to claim that the Mazda manual is incorrect. I was not specifically referring to your posts.

Unfortunately these oil-related threads have a tendency to turn into heated debates and or soapboxes which stray off the original poster's question/point/topic and thus become off topic.

Let's keep threads respectful to the original topic as well as on track and as helpful as possible, thanks once again.
Okay, thanks for the clarification. Yeah you're right. I belong to a lot of forums and the threads I hate the most are the "who's oil is better than the other guy's oil" threads. It's nauseating
 

truckster

2021.5 CX-9 Signature
Well, I guess I have one of the new ones that burns oil. I was out and about yesterday with the family when the oil light came on. Got home and parked it and waited for the engine to cool off and checked the dipstick. It was about 3/4 of a quart low. Low enough to set off the oil light. Topped it off this morning. I'll be taking it to the dealership this week to let them know what the deal is and to have them look for a leak mainly to just have this on record in case it gets worse. I'm sure I'll be told this is normal with all their vehicles....:confused:

Edit: It's a 2021.5 Signature with just under 9k on the odometer. First oil change was done by the dealership back in December at around 6000 miles
 
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Mazda CX-9 Signature
Maybe service filled out up on the low side to begin with? Did you check the dipstick after the oil change? And how you come up with 3/4qt low?
 

Kedis82ZE8

'12 GX 460,'07 G35x / '15 CX-5 AWD GT w/Tech Pkg
Contributor
 
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Mazda CX-9 Grand Touring 2016
It seems like a quart every 4,000 miles if my math is correct. That's not good, but it's probably not bad enough for Mazda to take action. Do get it on record. Let us know the outcome.

Am I correct in thinking that the problem is defective valve stem oil seals in the 2021 engines?

One of the required emission tests that many cars must pass regularly is a measurement of the hydrocarbons in the exhaust. How much oil burning is too much to pass the test? That might be a route to force a repair of the oil seals.
 
Last edited:
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2021 CX-9 Sig
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2021 CX-5 GT
Check to see if the Vin falls in the range indicated here:


If so, it will burn oil.

All the dealer will do is over fill the oil and hope for the best. I go from way over the top hole to right at the bottom hole at 4K mile.

Might be useful to merge this thread with the other thread:


And make it a sticky at the top of the page.
 

truckster

2021.5 CX-9 Signature
Check to see if the Vin falls in the range indicated here:


If so, it will burn oil.

All the dealer will do is over fill the oil and hope for the best. I go from way over the top hole to right at the bottom hole at 4K mile.

Might be useful to merge this thread with the other thread:


And make it a sticky at the top of the page.
yep, my VIN is lower than the one stated on the TSB. What a load of crap. This is not something I want to have to deal with for the remainder of my ownership of this thing.
 

erhayes

Contributor
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2021CX5 Reserve
The dealer was informed that my 2021 GTR low oil light came on during the free oil change. They offered to do an oil consumption test which I declined. I checked my oil level after I got home, and it was over the full hole by ~ 1/2inch. I'm not sure how much extra oil they pur in but, suspect it was at least an additional 1/2 quart or more.
 
Mazda's official 2.5T symptom troubleshooting sequence for high oil consumption (greater than 1 liter per 1200 miles):

1) Check appropriate oil viscosity --> replace oil with correct grade
2) Check oil leaks around engine area --> replace leaky component
3) Check PCV valve --> replace PCV valve
4) Check internal engine damage (cylinder, piston ring, intake/exhaust valve, cylhead gasket --> replace component
5) Check turbo intake side for leaks --> replace upstream intake components
6) Replace turbo
7) Verify fix
My car is 2021 CX 9 Grand Touring with 14K miles on it. It eats about 1/3 quart every 3900 miles. First time I toped it off at 3900 and again at around 7K ( so 2 times before reaching the 7500 miles). Service adviser told me that its due to the engine being Turbo and high compression and the heat in the summer, etc. He never informed me about the TSB, and also insisted that they don't top off oil and if the light comes on I have to bring it for a full oil change which I paid for. When the light comes on, the car requires 1/4 to 1/3 quart to bring the oil back up to the max level. With that said, I don't think the 1/4 quart down will cause engine damage unless you don't top it off right away and continue to drive it for long time without topping off. However, if we continue to top it off without a proper fix it will have long term consequences on the Catalytic converter, oxygen sensor, spark plugs and maybe carbon build up as well. Luckily, my car is a lease but still even if I return it I will lose some $$$ since car prices went up and I was planning to keep it as its residual is only $27K. I will wait for the fix and see, if they really found a way to do the fix without opening the engine head, I will go for it. Otherwise I will continue to top it off until lease end since I don't trust a local mechanic replacing my engine head, in my personal opinion it will never be the same.
 
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2017 Mazda 6 Sport
My car is 2021 CX 9 Grand Touring with 14K miles on it. It eats about 1/3 quart every 3900 miles. First time I toped it off at 3900 and again at around 7K ( so 2 times before reaching the 7500 miles). Service adviser told me that its due to the engine being Turbo and high compression and the heat in the summer, etc. He never informed me about the TSB, and also insisted that they don't top off oil and if the light comes on I have to bring it for a full oil change which I paid for. When the light comes on, the car requires 1/4 to 1/3 quart to bring the oil back up to the max level. With that said, I don't think the 1/4 quart down will cause engine damage unless you don't top it off right away and continue to drive it for long time without topping off. However, if we continue to top it off without a proper fix it will have long term consequences on the Catalytic converter, oxygen sensor, spark plugs and maybe carbon build up as well. Luckily, my car is a lease but still even if I return it I will lose some $$$ since car prices went up and I was planning to keep it as its residual is only $27K. I will wait for the fix and see, if they really found a way to do the fix without opening the engine head, I will go for it. Otherwise I will continue to top it off until lease end since I don't trust a local mechanic replacing my engine head, in my personal opinion it will never be the same.
Show them the TSB and point out #3 where it says they will top off or replace the oil free of charge until the fix comes out
 
Show them the TSB and point out #3 where it says they will top off or replace the oil free of charge until the fix comes out
Yes this is what I will be doing next time since I already topped it off this time. Problem is when the light comes on suddenly and you have plans you cant wait for a service appointment a week later, so I had to top it since I needed to take care of so many things and the earliest appointment was 3 days ahead
 
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Mazda CX-9 Grand Touring 2016
"It eats about 1/3 quart every 3900 miles"
That is not bad at all. A quart every 11,700 miles.

"Service adviser told me that its due to the engine being Turbo and high compression and the heat in the summer, etc."
He doesn't know as much as he thinks he does.

"He never informed me about the TSB"
Which he should have known about but didn't.

"insisted that they don't top off oil and if the light comes on I have to bring it for a full oil change"
Nonsense times two.

"When the light comes on, the car requires 1/4 to 1/3 quart to bring the oil back up to the max level."
I don't understand this. Low-but-safe is the lower mark. Max-and-safe is the upper mark. I'm assuming (perhaps incorrectly) that it takes a quart to move the level from the lower mark to the upper.

I've put six quarts into mine and had no problem at all. I generally put in 5-1/2 quarts at an oil change and bring the level up to the top mark. I don't understand the book's listed capacity of 5.1 quarts. 5.1 quarts = 4.8 litres which also makes no sense. 5 litres = about 5-1/4 quarts which makes more sense, but still doesn't match anything.
 
"It eats about 1/3 quart every 3900 miles"
That is not bad at all. A quart every 11,700 miles.

"Service adviser told me that its due to the engine being Turbo and high compression and the heat in the summer, etc."
He doesn't know as much as he thinks he does.

"He never informed me about the TSB"
Which he should have known about but didn't.

"insisted that they don't top off oil and if the light comes on I have to bring it for a full oil change"
Nonsense times two.

"When the light comes on, the car requires 1/4 to 1/3 quart to bring the oil back up to the max level."
I don't understand this. Low-but-safe is the lower mark. Max-and-safe is the upper mark. I'm assuming (perhaps incorrectly) that it takes a quart to move the level from the lower mark to the upper.

I've put six quarts into mine and had no problem at all. I generally put in 5-1/2 quarts at an oil change and bring the level up to the top mark. I don't understand the book's listed capacity of 5.1 quarts. 5.1 quarts = 4.8 litres which also makes no sense. 5 litres = about 5-1/4 quarts which makes more sense, but still doesn't match anything.
I don't understand this. Low-but-safe is the lower mark. Max-and-safe is the upper mark. I'm assuming (perhaps incorrectly) that it takes a quart to move the level from the lower mark to the upper.

This is not the first time it happened to me, 3-4 times now.. when the low oil light comes on I buy one full quart and put 1/4 of it which takes the oil level up to the high mark. I turn the car off check the level after 5 minutes and start adding then wait another 5 minutes for the added oil to settle before checking again.This time I added 1/3 instead of 1/4 which took the oil level from the low mark to a tad above the high mark. I wanted to add more but was told its not good to overfill. I think they made the sensor very sensitive which goes off if the car looses 1/4 quart or so. If that's not the case with yourself and others then I must be missing something here. I am checking the oil level and its going from the low hole to high with this 1/4 quart, so I don't think I am wrong or my car has issue with its sensor. I am buying Mobile 4w30 oil bottle from the gas station( I believe its one quart) and adding 1/3-1/4 of it.
 

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