Holden Jackeroo 3.0 TD

This is a new one... I have a 2002 T/D Jackeroo... I hope I dont have this to look forward to. This hose sounds like the air hose from the intercooler to the Throttle body...The black stuff can only be engine oil or you've had a meltdown and the hose is falling apart... As to your fuel usage I cant offer aconclusive explanation... I now use shell ULSD and I get an improvement of around 10% over the Woolies fuel I was using so Fuel quality could be a factor here if you filled up at your destination.

I've had my model (same as yours) from new - 82 on the clock now.
No evidence of the two issues you mention (yet). I do most of the straight forward servicing on mine (technical issues are done by a good small business).
Because that weeping hose has turbo pressure while the engine is running suggests that there is oil in there looking for a way out....what travels through must be getting burnt. Needing to be frank, I would not go to a dealer.....all trust here has been completely removed to the core......get a qualified completely "independent" evaluation. Does not sound to me like a hose issue.
No comment re the stains.
Re economy...... if your van catches a lot of air (or is heavy) that economy might well be ok.
I get 12.7L/100km towing a HD offroad soft top camper trailer on the blacktop - around 95k/hr average. Worst is about 16L/100km in dune and rough type country (trailer still on). Let us know how you go.

Sounds like a loose intercooler charge air hose, as you remove the intercooler to service these rigs. is fairly normal for the jacks and rodeos to have a bit of oil ' sludge' inside the hosing from service overfill or filling too fast etc.. Probably just needs a new clamp.

If you have just brought this rig make sure they have filled it with the best quality oil you can afford in a 5w30 5w50 etc. and changed both oil filters. The oil is critical to the operation of the injector system in these vehicles , and it takes 3 or more oil changes to fully flush any 'bad' oil from the dual oil systems.

Good oil makes for easy starts and better running.

Thanks for the praise, not an expert just silly enough to work for holden for a fair while......

Can double ease your mind. Mine has the oil in the hose too.
Apparently is normal, but not to be leaking out. My clamp is in v.g. condition, but I can see with a bit of use it may deteriorate and need replacing. Get a good one and the problem should be solved.

P.S. I too have a 1999 3.0 T/D Jack Manual. You are getting better economy than me. Mine Gets about 12.0 L/100km at best, travelling 80 km/h. Have got roof racks on though, shouldn't make that much difference though

D-Jack