Holden Commodore Engine Problems

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.

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.

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.

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.

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.

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.

Turning it off and on again reboots the computer, so it could be a fault with the computer or one of the sensors feeding information to it. Have a mechanic check the system for faults.

If it just stops without any warning then I would think it's electrical and I would be checking the ECU and sensors that send it signals. Particularly check the crank angle sensor. If it were a fuel problem I would expect to get a warning, such as the engine going off song like it was starving for fuel before stopping.

Have an experienced engine mechanic listen to the engine on a cold start to determine where the noise is coming from. They should be able to tell if it is valve lifters, or perhaps piston slap, which is probably what it is.

It's odd that there's such a disparity between steady-state highway driving and round town use. If the performance has dropped off I would be checking things like the exhaust backpressure, which might show up a blocked or partially blocked catalytic converter; if the performance hasn't altered look at the oxygen sensors.