Can hear the water boiling, then leaking under the left head light. Took it to the mechanics a few weeks ago and he replaced a gasket or something (Not very knowledgeable with cars) and it still leaks. New radiator cap is a good idea?
That will be coming from the overflow hose in the reserve tank (the bottle thing with a yellow cap). A new radiator cap should should fix it. But you should first make sure that the system has been bled so there is no air in there.
lol im definitely not an expert but if i were you i would check the whole engine bay for leaks. check all the hoses and seals and make sure you have enough coolant. open the radiator cap (when engine is cold) and add some pre mixed coolant or de-mineralised water until it is full. I would change the radiator cap also as if it is faulty it will make the overflow tank leak. If you are still having problems take it down to another mechanic, better to pay someone than risk damaging your engine or other components.
Get the engine up to operating temperature, then slightly undo the bleeding screw on top of the thermostat housing and air should escape. Keep opening and closing the screw until there is a steady steam of coolant with no air. Be careful not to scald yourself. If you don't know where the thermostat housing is, follow the top radiator hose to where it attaches to the engine and that is it.
Try bleeding it first, you might not need a new cap. After bleeding check the coolant level in the radiator when the engine has cooled down and top up if necessary.
