High mileage, worn out piston rings, pcv system not functioning properly,
The most common cause is an engine that overheated.
Over heating can blow a head gasket
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.
put on a new PCV valve.
There are several possibilities, but most common is that pressurized exhaust gas is vented into the coolant chamber around the engine. That causes the engine coolant to blow out through the vent and the engine will continuously overheat. Other possibilities are: coolant can blow into the crankcase, pressurized exhaust gas can blow between two adjacent cylinders, significantly reducing power and economy. Head gasket failure is almost always caused by engine overheating.
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.
The pressure of the sun causes the wind to blow.
Lack of or improper maintenance.
bad rings or really bad valve seals.
If it blows when trying to crank the engine, the starter is probably the failure.