Holden Commodore Problems

It does seem excessive, but first you should actually measure the fuel consumption so you really know what it is doing. Going by the gauge is no real indication of the consumption. If it is using half a tank for 100 km, then have it checked out; it could be a faulty oxygen sensor.

Intermittent problems are always difficult to find if they don't occur when the mechanic is there to witness it, but I would be looking at an engine sensor, crank angle or O2, as the most likely cause.

The 7-seater can be done, but the ability to fold away the rear seat is lost. The other problem is where to locate the spare wheel, as the LPG tank is located in the spare wheel well. It’s possible you could use a space-saver spare, or a can of foam for emergencies. The best thing to do is to consult an LPG installer and get their advice.

We asked our contacts at Impco, the company that developed the system for Holden, and they are at a loss to explain what might be the cause of your problem. Generally the system is very reliable, which leads them to think it's an intermittent problem, something like an electrical connection.

You're certainly doing enough kilometres to justify switching to LPG, but you need to establish the health of your engine before committing. It has already done over 200,000 km, and while the 3.8-  litre V6 is a pretty tough old nail you have to think its best is behind it. At the rate you travel it will have done more than 350,000 km within the next two years, and that's a lot. I would be reluctant to convert it because of is age and kays done, but if the engine is in good shape it could be worthwhile.

I wouldn't rush into doing anything, there doesn't appear to be much, if anything wrong with your car. It's not using oil or overheating, so leave it alone until there is a clearer sign that something is wrong. If you are concerned have another mechanic, one that you trust to tell you the truth, check it, as your current mechanic would seem to be trying to get you to spend money you might not need to spend.

Yes, there's no problem in converting the VYII V6 to LPG. Use a quality injection system and you shouldn't have any trouble.

It's odd that these problems should start after you had the new radiator fitted. I would suspect that whoever did the work did it poorly. Take it to an air-conditioning specialist.

It could be the diff itself or the diff mounts. Check the mounts first, if they check out ok, consult a diff specialist.

The engine is overheating, that's the gauge is telling you. You need to have a mechanic check it; any number of things could be causing it, from a blocked radiator to a blown head gasket. It's nothing to do with the grille.