Engine oil - oops!!

I think that Jackaroos need the thinner oil because oil is used to open the injectors.

If the oil is too thick the injectors can't open and the engine will not start.

Nev,
You need to shop around if usuing castrol sport edge 5-30 because the privce varies greatly . Recently Supercheap had it on special at 29.95 per 5 litres whereas others are selling it for up to $65. Check the K Mart price and whereas usually oil is not included in "sale"discount stuff, sometimes they will give 20% off.
It is not available in 20l drums in retail shops and you are better off pricewise with 5litre containers.
Suppose you realise it's a full synthetic.

it also takes 3 changes to get rid of the wrong oil, as its a shared system with the injector oil circuit which doesn't drain at change time.

castrol edge is only an MC synthetic not a true synthetic, thats why you can pick it up cheap, oh and even at its normal price its not expensive. Top quality full synthetics are fairly exxy, its not an old XF falcon you are putting oil in !!

Lots of the guys in tassie are running the mobil delvac from memory, buying it from the distributors by the 20lt drum. Check out australia4wd site - jackaroo section for further details. They even have a dedicated section for your engine because it is fairly unique.

I run full synthetic fluids in my jack, the g/box & diff oils are over $20 a litre. But she runs like a dream.

i hope you have better luck with your new mechanic
cheers