Radiator issues

[webman12]

Hissings sounds coming from the radiator. Sometimes, steam and radiator fluid blasts out of the overfill hose (I think that's what it's called. its the hose coming from the radiator cap). Is this normal? What could be the cause? The theromstat has been replaced and the water pump was replaced about 18 months ago. Any thoughts on this?

 

[Old Dog]

Well for some reason you have more pressure in the rad than the cap can hold. Your rad cap could be bad, You could be overheating ( Iwould have thought you would have said so) and building up to much press. in the system, or you may have put to much fluid in the rad. when it was cold and now when it gets warm and expands it has to go somewhere so it goes out the overflow like it should.
Does it overflow the overflow bottle?
Is it overheating?

 

[hole]

Well for some reason you have more pressure in the rad than the cap can hold. Your rad cap could be bad, You could be overheating ( Iwould have thought you would have said so) and building up to much press. in the system, or you may have put to much fluid in the rad. when it was cold and now when it gets warm and expands it has to go somewhere so it goes out the overflow like it should.
Does it overflow the overflow bottle?
Is it overheating?

Ditto. Whats the condition of the radiator, when you look inside is there any build up ?