Hello I am new here and is need of some serious help. I am mechanically inclined, but I am no master mechanic. I have a 2003 Honda Civic Hybrid with 132k miles. I started experiencing issues this winter with the heater blowing cold air then once in a while it would overheat. I would add fluids and it would seem to resolve the issue. As the weather warmed up, I had the chance to look at the car. I noticed that the coolant is always low in the radiator but once the car gets warm it pushes out antifreeze.
Whenever the car overheats it pushes fluids out of the reservoir tank and all over the car. This results in a low coolant level, so is that why it is overheating or is that a result of a head gasket ?
I changed the thermostat along with coolant flushes and heater core flush. The oil was recently changed and has no signs of antifreeze in it or vice versa. I also checked the spark plugs and other then some rust on a few of them they look ok. I enclosed photos of the spark plugs.
Since I took out the spark plugs and wiped them off and replaced them My car has been having issues. It refuses to start until I step on the gas pedal and then I got a p0301 code for a misfire but I also got a code for the other three cylinders could this be a result of me over-tightening or under-tightening the spark plugs?