how do you tell if the head or the block is cracked.the thermostat stuck when i was on the freeway and i drove it for a little while when it was hot.but i cranked up the heater and it cooled down.i replaced the thermostat and just put in a new head gasket.adn it is still getting hot.i don't know what to do,should i replace the head or get a new engine.and how long does it take to replace the engine?

 

Check your engine for codes, see what it says.....