I got a new cap from DMGRS a few months ago and almost immediately it started leaking from the overflow and there was steam coming out, i advised DMGRS of this and they sent me out another replacement cap.
I ran with the old cap on until the new replacement cap came and there was no more steam or coolant escaping so looks like there may be a small quantity of faulty caps.
I had only decided to change the cap as preventative maintenance type thing and DMGRS were very quick at sorting me out
