That actually varies from motor to motor. But commonly they will run safely till about 320 degrees, then it starts getting really tempremental. You take the chance of warping a cylinder wall or seizing a piston to the side wall.
Yes it sure can.
Your head gasket could be on the way out if there is oil in the coolant or it is consuming coolant. Replace the thermostat before you start suspecting the head gasket.
When the temp rises and falls , it is almost always a head gasket.
blocked colant passage gasket on wrong bad temp sen
It sounds like a blown head gasket to me. Take it to someone that has a exhaust gas measuring tool and they can tell you for sure if it is the head gasket.
Could be head gasket leaking
Because the temp gauge is not giving you the temperature of the water/steam in the radiator. You may have a bad head gasket or a cracked head causing the coolant to have that boiling effect.
It seals the exhaust manifold to the cylinder head so it doesn't leak and is made of a high temp material.
Blown intake manifold gasket or blown head gasket, figure on $600 to $650 to get intake gasket fixed and if a head gasket your looking at least $1,000.
blowed head gasket or cracked head
Temp sensor not working, cooling fan not working, blown head gasket.
You are OVERHEATING. You most likely have an intake or Head gasket problem.