Holden Astra Engine Problems

Based on your mechanic's diagnosis it would seem that the oxygen (02) sensor is probably faulty and needs replacing. There is no connection with the car's heater. If there is a problem with the heater it's different one.

It's suffering from fuel surge, and I would be looking into the fuel tank, to the anti-surge fuel pot.

It sounds as though there could be a problem with the belt, perhaps it hasn't been installed correctly, and the timing is now out. The best course would be to take it to a Holden dealer and get them to sort it out.

You don't normally see a water pump leak until you remove the timing belt cover, which is normally done when changing the camshaft timing belt. You don't say what work the dealer was carrying out, but perhaps the leak was discovered in the course of that work. That it was changed in 2009, almost four years ago, has no bearing on the issue, it may well be leaking again.

It would be wise to change the belt given that it’s five years since it was last changed. The consequences of it breaking are too dire to risk. Should it break it is most likely to result in extensive and expensive internal damage to the engine.

There should be no difference in the fuel if you sampled it at the fuel rail or the tank. The fuel at the rail is the fuel that is being delivered to the engine, and that's what matters most. You would appear to have a gripe with the dealer, and that appears to be what the Holden people are telling you, and should discuss your concerns with the dealer staff.

I doubt very much that it is the head gasket; I reckon you would have seen the engine temperature rise if it was a leaking head gasket. You won't know until you actually pull it apart and check it, but I would suspect it's the water pump that's leaking.

It's always hard when you know there's a problem, but it's never present when there's a mechanic with you. It's hard to diagnose when you can't hear it for yourself, so keep notes on when it occurs and anything you observe that might give the mechanic a clue. Things like, does it do it on cold starts, under acceleration, slowing down, at idle. Even better, record it on your smart phone so you replay it for the mechanic the next time you take it in.

I can understand your frustration, but it's a fact of life that cars do break down, and once the warranty has expired it costs money to fix them. It sounds like you have an extended warranty, so that should cover you for the cost of repairs. If you want to persist in chasing Holden you might be able to get part payment for the cost of repairs as a goodwill gesture.

This is a difficult one; there is no right or wrong answer. The car is four years old, and things do go wrong, even on cars that have only done a few kilometres. I can sympathise with you and generally I believe that components like the heater motor in your case should last longer than they sometimes do, but cars are machines and they don't always go smoothly. I would recommend that you contact Holden's Customer Assistance Service and lodge a claim for compensation. In the normal course of events I would expect them to offer you, at best, part compensation.