I have seen a few mentions of this in the forum - looks like some action are being taken:
Source: Mazda Valve Stem Seal Lawsuit Alleges Engines Fail
Source: Mazda Valve Stem Seal Lawsuit Alleges Engines Fail
Classy Actions - Valve Stem Seals
- Thread starter eightforty
- Start date
I went to the local Mazda Dealer with the settlement information. They told me to bring the car back with the low oil light on so they could see the code. Otherwise, they won't do anything. Mazda has known about the problem but doesn't plan to do anything about it. I sent an email to the settlement email, and they said they passed my comments on to Mazda. I asked what I could expect in next steps? Who would contact me regarding a fix. So far no response. The settlement is weak.
I believe the settlement extends the powertrain warranty on the impacted VIN range for another 2 years/24k miles, which provides some additional time should the issue get worse down the road.
Our (purchased new) 2021 CX-9 had the low oil warning at around 11k miles, or ~3,500 miles after the first oil change (which was filled to "F" on the dipstick). This happened before the TSB was issued, so the dealer documented the occurrence but didn't yet have a fix from Mazda; fast forward to the TSB, and the dealer agreed to do the stem seal replacement despite the fact that the low oil warning code had disappeared from Mazda's service history database. However, if you don't have the light, the dealer can perform an "oil consumption test," which involves the dealer changing the oil and measuring consumption over the following 1,200 miles (the oil change for the test is a paid service not covered under warranty).
On our vehicle, the TSB was completed at around 16k miles, and now at 38k miles the engine is still slowly consuming oil. Consumption appears to accelerate after ~3,000 miles from the oil change, so viscosity shear may play a role. The dealer's solution is to change the oil every 5k miles and slightly overfill it, which so far has kept the oil level well above the point where the low oil warning is triggered. According to the Mazda district service rep for my area, the stem seal issue is evidenced by very high oil consumption--enough to trigger the low oil warning in 800-1000 miles from full. This is why Mazda's "oil consumption test" for the issue is set at 1,200 miles.
Based on conversations with the Mazda service rep, cylinder borescope and compression tests performed on my engine (which were within spec), personal observations of consumption, and anecdotal evidence online, I suspect that there is an engine design issue which causes the 2.5T to slowly consume oil, especially when the 5W30 shears down a little. This "issue" may exist only if there's an expectation that it won't occur at all, but it may not indicate a departure from Mazda's expected design performance for the engine. Mazda doesn't want to admit that the engines inherently consume oil, but they don't seem to want to deny it, either. In my opinion, these engines should not consume oil, especially this early in their lifecycles (for reference, my Ford EcoBoost with 72k miles on it does not).
We like the car otherwise and have decided to continue to drive it and monitor the situation. The warranty extension offered by the settlement provides some additional "runway" should the problem get worse over time, but I suspect that it will still be a fight to get Mazda to correct it in the future. We also discovered a gear oil leak around an axle seal in the front, which appears to require significant disassembly to remedy. We just want a long-term reliable car which spends less time in the shop, and so far, Mazda has not impressed us.
