Radiator cap removal

[eenemini]

I've a slow leak of coolant. The repair shop suggested changing the radiator cap, so I bought a new one. The old cap will turn counter clockwise (but only with the help of a very large plumbers vise grip) and loosen, but will not come off. Is there a special tool for removing the cap? Should I tighten it back and pay a professional to do the cap replacement? Thanks if someone will help me with this. 2005 R50, not S model. I read the post by dakini below "need help disecting coolant problem" and it was very helpfull, but I still need to replace the radiator cap with the new one.

[minicoopers53]

Hi there

You need to turn it anti clockwise whilst pushing it down it will turn so far then feel like its stuck, push down on it and turn it again another 1/4 turn and you should then be able to remove it.