Dead At 30K Miles!? Mazda Skyactiv-G 2.5 CX30 Core / Blown Engine Teardown

Summary

In this video, the host performs a teardown of a rare Mazda Skyactiv engine, a 2.5-liter from a 2021 Mazda CX-30 with only 30,000 miles. Despite its low mileage, the engine suffered a premature failure. The teardown reveals unusual piston designs for high compression, signs of internal damage including rust and coolant seepage, and no obvious mechanical faults. The host speculates an overheating event as the cause, leaving viewers with an appreciation for Skyactiv's design and the mystery behind this engine's failure.

Takeaways

• 🔍 The video features a teardown of a Mazda Skyactiv engine, which is known for its rarity and durability.
• 🚗 The specific engine is a 2.5-liter Skyactiv G from a 2021 Mazda CX-30 with only 30,000 miles, indicating premature failure.
• 👨‍🔧 The host has a personal connection to Mazda, having owned and fixed many Mazda vehicles due to family ties with a retired Mazda Master Tech.
• 🔑 The Skyactiv engine design focuses on complete combustion, with unique piston shapes and exhaust manifolds to maximize efficiency.
• 🔄 The teardown process reveals no major external damage, but there are signs of internal rust and moisture, suggesting an overheating issue.
• 💧 The engine shows signs of coolant contamination in the oil, evidenced by a milky residue in the oil pan and on pistons.
• 👀 Upon closer inspection, one head bolt is found to be significantly looser than the others, which could indicate a loss of tension due to overheating.
• 🛠️ The teardown reveals that the engine's internals, such as the crankshaft and rod bearings, are in surprisingly good condition despite the presence of coolant and oil mixture.
• 🔍 The pistons from cylinders three and four are heavily gummed up, with the rings stuck in the ring land, suggesting severe carbon buildup and coolant contamination.
• 🤔 The cause of the engine failure remains unclear, but it is hypothesized to be an overheating situation that led to coolant consumption.
• 📦 The video concludes with an offer to sell parts from the teardown and other engines, directing interested viewers to contact the host for inquiries.

Q & A

What type of engine is being discussed in the script?

The script discusses a Mazda Skyactiv engine, specifically a 2.5-liter Skyactiv-G from a 2021 Mazda CX-30.

Why is the Mazda Skyactiv engine considered special?

The Mazda Skyactiv engine is special because it is centered around complete combustion with unique piston design, exhaust manifold, and overall focus on maximum combustion efficiency.

What issue is the engine in the script facing?

The engine in the script is facing a catastrophic failure despite having only 30,000 miles, which is considered premature for such an issue.

What is the narrator's relationship with Mazda vehicles?

The narrator has a strong connection with Mazda vehicles, having owned and fixed many Mazdas due to his father being a retired Mazda Master Tech.

What does the narrator find when inspecting the spark plugs of the engine?

The narrator finds that the original spark plugs do not show significant damage, with one being slightly wet but nothing bent or smashed.

What does the narrator observe about the engine's oil?

The narrator observes that the engine's oil does not have the correct consistency, appearing milky and mixed with water, indicating a possible issue with the engine.

What is the condition of the cylinder head and pistons after the engine teardown?

The cylinder head shows signs of coolant escape and rust around the valves, while the pistons, particularly in cylinders three and four, show significant wear and are stuck due to a mixture of coolant and carbon.

What does the narrator suspect caused the engine failure?

The narrator suspects an overheating situation that led to the consumption of coolant and damage to the pistons and cylinders.

What part of the engine teardown was particularly concerning to the narrator?

The narrator was particularly concerned when the pistons from cylinders three and four fell out easily, indicating severe damage and ring sticking due to a coolant and carbon mixture.

What is the narrator's final assessment of the Skyactiv engine after the teardown?

The narrator concludes that while the teardown revealed significant issues, the Skyactiv engine is generally a good engine, as evidenced by its unique design features and the lack of widespread reported problems.