这个车是不是 Engine坏了? 引擎压力测试只有 65 psi,不能启动引擎，事先没有任何征兆

儿子是新手，刚刚买了一部二手车给他开，结果今天说

The car started sputtering on the freeway, accelerating abnormally, check engine light came on。
The acceleration would not go full speed and flip back and forth。

The engine can't get started. No cranking noise when trying to start the engine.

拉去修车店，修车店说：
Engine is no good， it overheated， Blown head gaskets。 one of the  heater hoses burst out.
The engine won't crank over .

他又做了压力测试，结果显示只有65 PSI.

3 个 check engine light codes:

P1217 engine temperature overheat

P0725: Engine speed signal circuit

P1815: Manual mode swicth circuit No Up/Down signal

儿子说事先没有任何征兆，感觉是突然发生的。引擎怎么会突然死掉？地上也没有coolant.