Replace the radiator cap with the proper OEM cap. What engine seal are you talking about. If the car is overheating, severe engine damage can occur.
when your engine is hot it causes the water to boil and the water and the anti freeze will come out of the overflow pipe.
To the overflow tank and if the radiator has a cap,you will need to fill it with the engine cold.
In the overflow tank as well as the radiator. You should not do this while the engine is HOT!
With the hood open, on the passenger side there is the overflow container for the rad. The cap might be pressurized if the engine is hot. You add the antifreeze there.
Engine overheating will cause the anti-freeze to surge into the overflow tank. A blown head gasket will also cause the anti-freeze to surge into the overflow tank.
You really do not need to. Put the cap on and run the engine, the excess will flow into the overflow canister.
radiator cap might be leaking
A bubble sounds from the engine usually indicates that the engine is seriously overheating. It is best to turn off the engine and call a mechanic. Adding antifreeze may help, but it is likely leaking somewhere.
Heat from the engine causes liquid to expand. It used to overflow onto the ground if it caused enough pressure to open the radiator cap. The overflow tanks were installed to automatically catch and return the coolant to the cooling system.
could be a bad hose, bad radiator, bad gaskets, bad Head... find out if there is antifreeze leaking, and where from. if there isn't a visible leak, check your overflow for engine oil if the overflow is black, then it's a blown head gasket, and you;r out some bucks.
Remove the radiator cap when the engine is cool and add the coolant into the radiator or you can add to the coolant overflow bottle. DON'T remove the radiator cap when the engine is hot!!!
It should be ok as there is nothing too terrible in the coolant. Excess antifreeze will just overflow. Try and get some out. Antifreeze can cause paint issues if the concentration is high enough...RR