1985 Holden Drover Pricing and Specs

There are literally hundreds of things that can cause a check-engine light in a modern, computer-controlled car. A problem with the ignition, fuel system, emissions-control system, air-intake, lubrication, cooling and much, much more can cause this light to illuminate.

The best way to proceed is to have the vehicle electronically scanned. That way, the computer can tell the mechanic where the problem is and, hopefully, precisely what’s causing the check-engine light to flicker on.

For the record, however, a common fault with the V6 engine in this series of Commodores is a stretched timing chain that the computer interprets as incorrect valve timing (which it is). Plenty of owners of this model have discovered this as the cause of their check-engine light.

The first conclusion many mechanics will arrive at is that the engine’s head gasket has blown, allowing the oil and coolant to mix. Have a look at the dipstick. If the engine oil is milky, then this is a very real possibility. Perhaps when the cylinder head was replaced, the gasket has not sealed properly.

But if the oil cooler was replaced because it was leaking into the radiator (which is pretty common) then you might find that the oil you’re still seeing is just residual oil from the previous failure, and not a problem at all. Even so, it would be wise to replace the coolant and flush the system to try to eradicate all traces of the old oil.

A workshop can perform a chemical-based test to see if the head gasket is leaking. It’s worth the relatively small cost to rule this out and begin to look elsewhere.

The most problematic of the Cruze transmissions were the six-speed automatic fitted to Cruzes built between 2011 and 2013. Holden actually instituted a special repair program for owners of these cars and extended the warranty period on those that had been repaired under the terms of that program.

The 2015 car you’re looking at should not have these problems, but the Cruze itself was plague by a long list of other faults including oil and coolant leaks, overheating, cracked cylinder heads and more. To be fair, the later the build date, the less likely the problems were to occur, but any Cruze needs a careful, independent inspection before money changes hands.