(1) The surface of the cylinder head and block is not even, which causes air leakage and water leakage and burns out;
(2) Cylinder head bolts, nuts tightening degree is not enough or uneven, resulting in uneven force and leakage, then damage;
(3) Ignition is not the right time and the use of fuel labels, causing deflagration and burned;
(4) Overload is too large, so that the engine load is too heavy to produce high temperature and burn out;
(5) Insufficient cooling water or oil, engine temperature is too high and burned.