— Mazda valve stem seal problems have caused a class action lawsuit for former and current lessees and owners of 2021 Mazda CX-30, CX-5, CX-9, Mazda3 and Mazda6 vehicles.
The Mazda vehicles are allegedly equipped with defective valve stem seals that allow engine oil to leak into the combustion chambers.
The valve stem seal problems allegedly cause excessive oil consumption between regular oil change intervals which increases the risk of engine damage and failure.
According to the class action lawsuit, Mazda has known about the alleged valve stem seal problems since the vehicles were first sold but has concealed its knowledge to continue selling the vehicles. Additionally, Mazda dealers allegedly have either refused or been unable to repair the vehicles.
Mazda issued a bulletin in October 2021 regarding excessive oil consumption which said, “it is very likely that valve stem seal damage is causing oil to leak into the combustion chamber.”
In addition to not having a fix for the Mazda valve stem seal problems, the automaker has not recalled the vehicles and hasn't reimbursed lessees and owners over the oil consumption issue.
The valve stem seal class action asserts Mazda saves a lot of money by allegedly avoiding its warranty claims and by not recalling the vehicles.
According to the lawsuit, the Mazda valve stem seal should "prevent engine oil from contaminating the air/fuel mixture in the Class Vehicle’s engine’s combustion chamber and prevent intake and exhaust gases from contaminating the oil in the cylinder head and the rest of the engine."
The plaintiff also alleges the Mazda valve stem seals should last the life of a vehicle.
The Mazda valve stem seal problems allegedly create carbon deposits on the valves and piston crowns and contaminates the spark plugs which cause the cylinders to lose power. The lawsuit further claims the engine valves fail to seal and the engines run rough due to a lack of compression.
The plaintiff also alleges defective Mazda valve stem seals may cause excess exhaust gases in the crankcase which damages other systems.
Mazda Valve Stem Seal Bulletins
The class action lawsuit says that in November 2020, Mazda issued “M-Tip” bulletin MT-005/20 for 2021 CX-5, 2021 CX-9 and 2021 Mazda6 vehicles. According to the lawsuit, the bulletin said, “Some customers may complain about high engine oil consumption.”
Bulletin MT-005/20 told dealers to measure engine oil consumption after driving 1,200 miles and “[n]o repair is necessary” if a vehicle consumes less than one liter (1.06 quarts) of engine oil within 1,200 miles."
However, the lawsuit says Mazda’s owner’s manual and warranty state the recommended oil service is the earlier of 10,000 miles or one year.
"Thus, according to Mazda, a vehicle needs to consume more than eight quarts of engine oil in between recommended oil change intervals in order to necessitate a repair for excess oil consumption, and a vehicle that consumes, for instance, 7 quarts of engine oil in between oil changes is purportedly normal and within specifications." — Mazda class action lawsuit
In October 2021, Mazda issued technical service bulletin 01-012/21 for 2021 Mazda CX-30, CX-5, CX-9, Mazda3 and Mazda6 vehicles that were built before September 14, 2021.
“Some vehicles may have a ‘LOW ENGINE OIL LEVEL’ warning message and a CHECK ENGINE light illuminated in the instrument cluster, along with DTC P250F:00 stored in memory. . . . Upon inspecting the engine oil level, the level is found to be low and there doesn’t appear to be any trace of oil leakage in the engine compartment. This concern usually occurs when the mileage reaches approximately 3,100 – 4,700 miles (5,000 - 7,500km) and may also occur again after replacing or topping off the engine oil.” — TSB 01-012/21
The class action goes on to say the TSB told dealerships, “[t]he root cause of this concern has not been identified yet, therefore a repair procedure will be announced at a later date. Since this issue has been reported after a valve stem seal modification, it is very likely that valve stem seal damage is causing oil to leak into the combustion chamber.”
The Mazda TSB further says technicians should “verify that the oil level is low” and “verify that there is no oil leakage in the engine compartment. If no oil leakage is found, top off the engine oil to the FULL level as a temporary measure.”
Dealers are told to tell Mazda customers a small amount of engine oil may be leaking into the combustion chamber, but it won't cause any immediate engine damage and customers can continue driving the vehicles.
The bulletin says warning messages will disappear when engine oil is added to the vehicle.
According to the Mazda valve stem seal lawsuit, "Mazda does not claim that engine oil leaking into the combustion chamber will not cause long term engine damage, but only that it purportedly 'will not cause any immediate damage.'”
The Mazda class action lawsuit was filed by Washington plaintiff Gary Guthrie who purchased a new 2021 Mazda CX-30.
The Mazda valve stem seal class action lawsuit was filed in the U.S. District Court for the Central District of California, Southern Division: Gary Guthrie v. Mazda Motor of America, Inc.
The plaintiff is represented by Lemberg Law, LLC.