
Cylinder head gaskets are replaced when coolant and oil leaks appear at the junction of the cylinder head with the cylinder block

If the valve does not fit tightly on the seat, then gaps are formed in some areas of the valve and seat.
In this case, gases under pressure and at high speed pass into the formed gaps, so in this place the chamfers are subject to severe corrosion and the valve fits worse on the seat.

Two compression rings and one oil scraper are installed on the piston.
Compression rings are designed to prevent gases from escaping into the crankcase when they are compressed and expanded