Morning all, I wonder if anybody can shed some light on this. I've just replaced a leaking radiator on a 1997 BMW Z3 1.9 with a replacement bought off ebay. The new rad looks almost identical and fits the car perfectly. Only problem though is the cap off the original BMW rad wont fit the new replacement rad, the threads on the new rad bottle apear to be thicker but the overall diameter is the same. The cap will go on if I use excessive force but still does not seal properly (if you squeeze one of the hose's you can hear air hissing out of the cap).
Have the caps been redesigned on later rads? Or is it likely to need a new cap specific to that make of non genuinne rad?
Anybody else had this problem?
cheers
Russ.

Any I have encountered have a very robust looking thread, Rover 75/MG ZT uses the same fitting.
I have replaced two or three usually costs about a tenner from factors or off ebay,