2021 CX-9 Burning oil

Hello! Long time lurker here. I have a 2021 CX-9 Signature and absolutely love it! I'm currently @ 9000mi and the low oil warning light came on a few days ago, confirmed by the dipstick. I did my last oil change @ 5000mi and by my estimate the car consumed around 1qt of oil in the last 4000mi. I use KNN oil filter and Castrol Edge Max Performance 5w30. No blue smoke from the exhaust so I'm suspecting the PCV valve. Any thoughts?

View attachment 303352
Check the oil once a month. Sometimes oil seems to evaporate a little in hot weather. I also think some of it goes through the PCV valve. I don't know that means anything's wrong with it unless you get a check engine light.
 
I've been driving since the mid 70's and owned numerous cars, both domestic and foreign makes, and have never had an oil burner.

With my 2019 CX-9 GT FWD I never check the oil to be honest and would never expect there to be a problem with oil consumption in a 'new' vehicle with only 13K miles.

For fun after reading this thread yesterday I went out and checked mine and it's only about a third of the way down from the 'full' mark. My next oil change is about 2.4K miles away and think it'll be fine but will pay more attention thanks to this discussion.
 
Just got the car back from the dealership. So apparently, as expected, the SA said it was normal for a turbocharged car to consume "a lot" of oil especially my engine was still new. "Still lubricating the seals and bearings" he said. He didn't seem so suprised when I told him about the low oil level warning light. They did a 10K service (oil change and inspection). I checked the oil level when I got home and it was right above the HIGH mark so obviously they put more than 5.1qts. I asked the SA when should I be concerned about oil consumption. He said when my car gets to a "high mileage" 🤔🤷‍♂️🤦‍♂️.

Anyway, looks like I'll just the oil level monthly and always keep some fresh 5W30 handy.

I have a turbocharged Mercedes CLA250 with 100K miles on it and doesn't burn a drop of oil. My 2021 CX-9 is officialy an OIL BURNER!
 
Last edited:
Just got the car back from the dealership. So apparently, as expected, the SA said it was normal for a turbocharged car to consume "a lot" of oil especially my engine was still new. "Still lubricating the seals and bearings" he said. He didn't seem so suprised when I told him about the low oil level warning light. They did a 10K service (oil change and inspection). I checked the oil level when I got home and it was right above the HIGH mark so obviously they put more than 5.1qts. I asked the SA when should I be concerned about oil consumption. He said when my car gets to a "high mileage" 🤔🤷‍♂️🤦‍♂️.

Anyway, looks like I'll just the oil level monthly and always keep some fresh 5W30 handy.

I have a turbocharged Mercedes CLA250 with 100K miles on it and doesn't burn a drop of oil. My 2021 CX-9 is officialy an OIL BURNER!
Your service advisor is a giant BS artist and 99 percent of them don't know their a$$ from their elbow. " Still lubricating the seals and bearings?" LMFAO. It's hard to find ANY good tech, let alone the joke service advisors and techs at stealershops. Go to another one or search Google for a top rated indie shop and get an impartial opinion. Stealershops ALWAYS says everything is "normal". They are pre programmed robots with no brain.
 
Just got the car back from the dealership. So apparently, as expected, the SA said it was normal for a turbocharged car to consume "a lot" of oil especially my engine was still new. "Still lubricating the seals and bearings" he said. He didn't seem so suprised when I told him about the low oil level warning light. They did a 10K service (oil change and inspection). I checked the oil level when I got home and it was right above the HIGH mark so obviously they put more than 5.1qts. I asked the SA when should I be concerned about oil consumption. He said when my car gets to a "high mileage" 🤔🤷‍♂️🤦‍♂️.

Anyway, looks like I'll just the oil level monthly and always keep some fresh 5W30 handy.

I have a turbocharged Mercedes CLA250 with 100K miles on it and doesn't burn a drop of oil. My 2021 CX-9 is officialy an OIL BURNER!

Keep in mind that your dealer does not have the final word. You have the option to get a second opinion from a different dealer, or to escalate your case to Mazda Corporate if you feel that your issue isn't resolved or if you think your dealership experience was unsatisfactory.
 
I agree, that service writer knows nothing about a turbocharged engine.* I've had two, Volvo and this Mazda. Neither burned oil. The Volvo turbo was still going strong when I sold it at 202,000 miles. This Mazda turbo remains fine. If it ever stops lubricating the seals and bearings the turbocharger becomes an expensive door stop. Get really solid stats on the oil consumption and bring the problem to Mazda corporate. Be sure to save all the paperwork you have from your trips to the dealerships for this. Be sure the work orders state the problem of excessive oil consumption, not just some vague order to inspect the engine.

*While we expect the service writers to know everything about our cars, they are actually commission based sales people of service work. If they don't sell service, they get fired. You can also discuss any problem with the service manager, the service writers' boss. Don't berate the service writer...the manager hired him...just ask for better technical advice, possibly from a Mazda regional rep who may come by the dealership from time to time.
 
Last edited:
While I wouldn't like to see my engine use 1Q per 4K miles, it is NOT considered an oil burner. Maybe time to try a different 5w30 oil. Your dipstick reading doesn't indicate a 1Q low from Max. Ed and
 
Hello! Long time lurker here. I have a 2021 CX-9 Signature and absolutely love it! I'm currently @ 9000mi and the low oil warning light came on a few days ago, confirmed by the dipstick. I did my last oil change @ 5000mi and by my estimate the car consumed around 1qt of oil in the last 4000mi. I use KNN oil filter and Castrol Edge Max Performance 5w30. No blue smoke from the exhaust so I'm suspecting the PCV valve. Any thoughts?

View attachment 303352

Yes the oil level was a tad above middle of the low/high indicators of the dipstick. It was the entire 5qt jug.


It looks like you lost a pint to me. 5 qts only puts it slightly over half.
 
Then the consumption may be only ~ 1q per 8,000 miles. I think you need to do a much better effort to measure how much oil you are consuming. Possibly us a graduated cylinder and add a small amount at a time to find out how much is needed to replace at a given mileage. Ed
 
The engine is fine at the high oil mark on the dipstick and at the low oil mark on the stick. Fill it cold to the high mark, check the cold level frequently, note the miles it took from high to low, add back to the high line, note how much was added. Many quart oil bottles have graduations on the side to show how much remains in the bottle.
 
Glad I found this thread. I have a 2021 CX-9 Touring with 6300 miles on it, no oil changes yet. Oil level light just come on tonight. Was planning to have the first service done at the dealer in the next few weeks, but it looks like it’ll be ASAP now.
 
Glad I found this thread. I have a 2021 CX-9 Touring with 6300 miles on it, no oil changes yet. Oil level light just come on tonight. Was planning to have the first service done at the dealer in the next few weeks, but it looks like it’ll be ASAP now.

It's possible that it could be this issue: TSB 01-12/21
 
It's possible that it could be this issue: TSB 01-12/21
Thanks! I’ll be sure to mention this when I bring it in Monday afternoon. One more question - I was planning to top it up before bringing it in, as I’m not keen on driving around today low on oil, but would it better to bring it to them low?
 
It's possible that it could be this issue: TSB 01-12/21
Thanks for the TSB. This means Mazda hasn’t figured out what happened to this oil burning issue on these 2021 2.5T’s. Keep in mind that the car manufacture’s guideline of “excessive oil consumption” which is considered having problem and needs to get fixed under warranty is to use 1 quart of oil per 1,000 miles.

Mazda must have regretted now putting in an oil level sensor in their engines in recent years ⋯ :rolleyes:
 
I wonder if this will effect those who ad their engines replaced from the coolant leak. Curious if they fixed one problem and now have another.
 
Thanks! I’ll be sure to mention this when I bring it in Monday afternoon. One more question - I was planning to top it up before bringing it in, as I’m not keen on driving around today low on oil, but would it better to bring it to them low?
You’d want to leave the oil level alone to show the dealer the low oil level condition. Even the oil level is at Min / Add mark of the dipstick when you measured it the first thing in the morning before the engine start, the car is safe to drive at least for a short distance (20 ~ 100 miles?). If you’re really concerned, you can use free Mazda Roadside Assistance to tow your CX-9 to the dealership.

Once I drove my 2018 Toyota Yaris iA (Mazda2 in disguise) for a 355-mile road trip just after a Toyota dealer did a free oil change, the oil level was so low that it wouldn’t show on the dipstick the next morning! There was at least 2 quarts of oil (out of 4.4 ~ 4.6 quarts of oil capacity) leaked out from drain plug! The Yaris iA doesn’t have Low Oil Level Warning Light. And the Low Oil Pressure Warning Light had never on, so it’s safe to say the engine didn’t suffer too much damage from this incident.

You certainly don’t want to drive the car if the Low Oil Pressure Warning Light is on!

B35E8188-3C0E-4BA0-BD5B-C6FFBB7144EB.jpeg
 
I wonder if this will effect those who ad their engines replaced from the coolant leak. Curious if they fixed one problem and now have another.
IMO these 2 (major) issues going on on the 2.5T shouldn’t be related, and any revisions to the cylinder head and exhaust gasket for coolant leak problem can’t cause any more oil consumption. Most likely this oil consumption issue is caused by a batch of inferior parts, such as the valve stem seals or piston rings, got introduced into the engine assembly line due to poor quality control.
 
Last edited:
^ I agree.

One of the things I have liked about Mazda is their engines have not been known to consume that much oil. Our 07 2.3L, 14 3 with the 2.5L and 15 3 with the 2.0L did not consume any oil. My current 2.5T only has 800 miles on it so I'm not sure where that stands. My VIN is 2,500 higher than the TSB so I'm in the safe zone, for now. With low tension piston rings, lighter viscosity, oil consumption in some brands has been the norm. As others have stated, manufacturers have a tolerance level for oil consumption, usually up to 1qt per 1k miles.

Years ago, I had a Corolla that would consume a quart every 3k miles. Same with my 05 Accord. Both cars ran like new with nearly 200k miles on them. It's more of an inconvenience thing. Ideally, I don't want my engines consuming any oil.
 
*regarding capacity, if you notice the manual specifically states to check the oil you want to get the car up to operating temperature, then wait at least 5 minutes. What you'll notice is the oil level will read higher doing it this way vs cold. I think that could be why they call for 5.1qts. 5.1qts when checked cold could read slightly lower than the top hole, but if you check it 5 or so minutes after the car has been driven, you may find it to reach that hole. Try that.
 
Back