Sorry to intercept this dipstick-tugging thread!
But having read what you said Teutonic_Tamer on one of my posts re; Quantum Synta III 5w30 not being 'as good' as the Castrol equivilent, I have actually ran out of the Synta III, and in case I need to top up between now and my next oil change, would I be right to assume I could use a Castrol Edge 5w30 oil to top up? Or is it not worth mixing it with the Quantum until I do a full oil change?
Basically, I can only get a 5L bottle of Quantum so if I have to go down that road I might as well buy 5L's worth of SLX and do another oil change...
Thanks mate,
Sean