What are the symptoms of a slightly blown head gasket?

[BraydenLee]

The symptoms of a slightly blown head gasket are: decreased power, weak vehicle performance, abnormally high engine temperature, poor operation, low coolant level, oil in the coolant, and water in the engine oil. Additionally, after a cold start, open the radiator cap and observe if the coolant is calm. If there is noticeable coolant spilling or spraying out from the radiator filler neck, this indicates a blown head gasket. If the starting system, fuel supply system, and ignition system are all functioning normally but the engine cannot be restarted after being shut down for a long time, the head gasket may be damaged. You can also start the engine and check if water or steam sprays out from the spark plug holes to confirm whether the head gasket is burnt. The head gasket is installed between the cylinder head and the engine block, secured by cylinder head bolts to ensure cylinder sealing and prevent leakage of combustion gases, coolant, and lubricating oil. A blown head gasket can be simply understood as an impact-related failure between the piston and the cylinder liner or the gasket itself.