Thermostat probably needs replacing They can stick not allowing enough water to flow around the engine block If the engine overheats it can warp the head or blow the head gasket
Over heating can blow a head gasket
The most common cause is an engine that overheated.
blow back or blow-by is pressure that builds up inside the engine causing oil to be blown out of vent,oil stick,oil filler cap, or into air breather.. Causes of blow-by ---- Bad PVC valve (Positive Crankcase Ventilation ) Worse case is worn piston rings or cylinder walls - engine needs to be rebuilt. http://en.wikipedia.org/wiki/PCV_valve
Plugged PCV valve or hose
If it is coming out around the top of the stick, you have either a plugged pcv valve/crankcase orifice tube or excessive engine blow by. Blow by is the normal leakage past the piston rings. Excessive blow by will require a new/rebuilt engine.
Blow by is caused when combustion gases get past the piston into the crank case. The cause will be piston, rings, or cylinder wall.
Blow by or blow past is leakage of combustion gas between ring and liner surface. It may happe due to wear of liner surface. Causes for it: lubrication fail, suffing, older engine etc.
It's called "blow-by", a condition caused by combustion gasses leaking past the piston rings. It's an indication that the engine has not been adequately maintained. That means that you are in need of a new set of piston rings.
Could be low coolant, stuck thermostat, bad heater control head (if climate control)
Anything that causes the engine to run hot, like a faulty thermostat, can cause the head gasket to blow. also say a coolant hose ruptures, all the coolant is then drained from the radiator and the engine is then essentially running with no way to cool down, gasket blows. there are many ways for the engine to run hot, but it is the main reason a head gasket would blow out.
How do you blow a engine turbo.