Any time a vehicle with the DOHC Holden V6 is mentioned as having a starting problem or check-engine light illuminated, mechanics will often go straight to the engine’s timing chain to check its wear. That’s because this engine is notorious for such antics and, when they occur, it can often mean poor starting and the dreaded check-engine light.

However, in this case, the engine in question was an Isuzu-designed unit that doesn’t seem to have the same rash of timing chain problems. Which means you need to go back to basics and have the vehicle scanned to see if the onboard computer has logged the root cause of any problems.

The fact that the check engine light is flickering and the starting problem is an intermittent one could mean anything, but a good place to start checking would be the various earthing points around the vehicle. Bad earths are a common cause for this sort of problem.

The condition of the car’s battery is also a smart place to begin investigations. A lack of power in the battery is enough to make a lot of electronically fuel-injected vehicles throw in the towel on a random basis.

When an engine (petrol or diesel) inhales water through its air-intake system, it's never usually a good outcome. Because water is – as is any liquid – non-compressible, the engine's pistons will try to achieve that but, in the process, the engine will lock up and all sorts of internal carnage can ensue.

If you're lucky, the damage will be fixable but can still involve bent con-rods, broken pistons and bent valves. If the lock up was more severe, there's a chance that the engine block could be cracked or a con-rod has broken and punched a hole through the crankcase. Sometimes the force of the lock up is sufficient to smash the main bearing caps and throw the crankshaft out of place. In any of those latter cases, the whole engine would be considered a total loss.

But even if you've gotten away with a bent con-rod or two, you'd still need to rebuild the entire engine and, in the context of a 2004 Rodeo ute, you might find you're spending more money than the vehicle is actually worth.

A potentially better idea would be to find a good, tested second-hand engine from a wrecking yard or any other sort of damaged Rodeo and do a relatively simple heart transplant.

It's odd that Holden's diagnostic equipment failed to find the problem oxygen sensors. In any case it is good to get an outcome, and it's something any other owner with a fuel consumption problem should think about checking.