Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
A Gen 3 with 280k on the clock.
You could try the 2 litres of kerosene first, but Gen 3 onwards are prone to lifter roller wheel and cam lobe failure, broken valve springs etc.
After you drop the oil and filter, fill the new filter with new oil prior to fitment, gets oil pressure faster.
Please only ask once, otherwise you may pay two techs for the same answer.
I have past on your second request to customer service.
What oil is in the engine now, and how long since last oil change?
I have seen oil pump issues on LS engines, not often but does happen.
Sounds like for high kms now, you should think about adding a product called "lifter free" or Nulon E10 or E20 when you change it now.
It does sound like a TECH 2 data display will show what oil pressure the engine has, both at hot idle, and at 2000 rpm.
This might show the pressure to be low in both cases.
At 280000km, I would think it is due for an engine rebuild if it hasn't been apart before.
You could be suffering from poor drain back to the sump when you get up it, or the oil is getting a little thin for the slightly larger clearances it has.
You could try a slightly thicker oil, say 10w50.
If you do go for a rebuild, I would go for aftermarket tiebar lifters and chuck the factory plastic lifter guides in the bin.
A package from Comp Cams, camshaft, lifters, rockers, springs etc REALLY wakes them up, as well as a MAFLESS tune.
I've driven a few with 400rwkw aspirated, absolute weapons.
I don't think you want to go that far, just showing what their potential is.
You might even find that adding a litre of thicker oil now, if it is low, might help for now.
Do you need any further help?
I hope my advice has been of assistance to you.