Hi If its a D5WZ it definately comes apart, small torx headed bolts to remove back cover. Never heard of them being sealed units. You may find this link usefull for parts http://myworld.ebay.co.uk/dieselheaters4u&...:MEFSX:SELLERID Hi, thanks for the reply, its def a d5w z according to the label on it so thats great, all ill have to do is get a plug and change it over ;) Thanks for the quick and informative reply :)