No, he doesn't want to put any castrol oil in there, its the work of satan, and will do more harm from good, especially if its already nackered - its renowned for clogging up engines and adding loads of excess gunk in there, its a pile of crap really, why people still use it is beyond me. best bet is some Millers oil (i use the XSS stuff, 10w40 in everything) or some Valvoline durablend, although the normal petrol engine oils from Millers is fine, they know their stuff.