Holden Astra Engine Problems

Going back to first principles, anywhere that a power wire that should be insulated is allowed to touch an earthed part of the car is a potential source of a short circuit. As such, there are about a million places where a wire or cable carrying 12 volts from the battery could be shorting out by touching an earthed part of the car.

Typical sites of a short-circuit include anywhere where a wire runs through a metal bulkhead (say, from the car’s interior to its engine bay) anywhere a wire is continually flexing (the wiring inside a door jamb where it passes through the body) a switch of any sort or anywhere else where friction could have worn away the wire’s insulation. Sometimes the insulation just gets old and falls off the wire (Mercedes-Benz cars from the mid-90s were notorious for this).

The clue will be in what components have suddenly stopped working. Checking the fuse box to see what fuses have blown in response to the short circuit is also a good indicator or where to start looking. If you suspect the short-circuit is at the battery itself, there will be no need for forensic investigation; a short at the battery will produce a violent spark and lots of smoke. Unless, of course, the car is fitted with a great safety feature called a circuit breaker on or near the positive battery terminal. If you’ve suddenly lost all power to the car, that’s where to start looking.

Finally, don’t assume that a loss of power to the car or some of its components is due to a short circuit. Sometimes a fuse can simply fail for no good reason and call a halt to play. If you’re unsure, an auto electrician can work miracles that the rest of us cannot generally fully comprehend.

You could have a fault with the car’s wiring. The starter-motor takes its power from the fat, red and black leads that attach to the battery, but it also needs a low-voltage signal from the ignition key that tells it to do its thing. If there’s any sort of loose or missing wire, you might not be making the necessary electrical connections. You could also find that there’s an on-board security system that is blocking the starter-motor from turning. You could even find that the ignition key has a flat battery and is not unlocking the car’s on-board computer.

You say that the battery has voltage, but I wonder how you checked this. You can often put a multimeter across the battery terminals and see 12 volts, but this can be what’s called a surface charge that’s strong enough to light up the dashboard, but then disappears when you put the battery under load (by trying to start the car). Attach the multimeter and check the voltage while actually trying to start the engine. You may find you have a dead battery after all.

Having a bolt snap off while you’re undoing it is a royal pain and can bring take the car off the road if it’s a critical fastener. You’re probably best off visiting a mechanical engineering shop (or good workshop) who will have the tools necessary to remove the broken chunk of bolt still lodged in the car.

Techniques vary according to how much bolt is still showing, access to it and even what it’s made from. In some cases, the engineer will use what’s called a bolt-extractor kit which screws into the broken bolt and extracts it without damaging the existing threads. If you’re lucky there will still be enough of the broken bolt exposed to allow the use of vice-grips to remove it. Sometimes a small section of new metal can be welded to the broken stud or bolt to give purchase and in extreme cases there’s even a process called spark eroding which is more expensive but can really save the day. The last resort is usually drilling the broken bolt out as this can destroy the threads in the part, requiring even more work to ultimately replace the fastener. In each case, penetrating fluid and/or the application of heat will be the first step to try to free or loosen the broken fastener before trying to extract it.

This shouldn't be too difficult, as the 2003 Astra was only available with a petrol engine. If your car was a diesel-powered car (available in the next generation of Astra) the situation could be much more complicated. As it is, however, you should really only need to add fresh fuel to the tank, switch on the ignition for a few seconds to allow the fuel pump to prime the engine and then hit the starter. Don't crank the engine for long periods if it's a bit slow to start a this will drain the battery and potentially overheat the starter motor. Instead, try starting the engine in bursts of a few seconds at a time with a little time between to let things cool down.

Sometimes, however, the fuel pump won't appreciate being allowed to run dry and this can cause internal damage to the pump sufficient for it to need replacement. Generally, though, if you can hear the pump buzzing with the ignition on, the pump is working. In some extreme cases, the pump may not be able to prime the engine and the solution then is to spray a little starter fluid down the intake system to start the engine and hopefully allow the pump to catch up. But be warned, this is a dangerous process and should only be tried by somebody who knows what they're doing. It also involves undoing some of the trunking or piping to gain access to the engine's intake.

The other potential hazard with running a car dry of fuel is that you'll drag all the silt, rust and dirt that once sat harmlessly in the bottom of the tank through the engine and into the fuel system. So you would be well advised to change the fuel filters and check that no rubbish has entered the system.

You’d expect any noise from under a car’s bonnet to be caused by the engine, but if this noise occurs before you’ve started the engine, you’re on to a real mystery. Perhaps the noise can be heard as you crank the engine but before it actually fires? If that’s the case, the clunk or knock could be coming from the starter motor. Or perhaps the action of the starter motor is causing the engine to rock back and forth on worn engine mounts and allowing the engine to hit on the cross-member or some other component under the bonnet. Perhaps it’s a loose exhaust system that’s banging on something as you crank the engine. Once the engine fires and is running, the frequency of its vibrations changes and the clunk goes away.

But I’m afraid that without more information, this one remains a mystery to us.

The first response of most mechanics on this would be that you have a head gasket leak in the engine. Coolant in the oil and/or oil in the coolant are classic symptoms of this. It happens because the faulty head gasket allows the two fluids to mix but, depending on exactly where the gasket fails, you don’t necessary get both symptoms. A workshop can pressure test the engine’s cooling system and perform what’s called a TK test to show up any contaminants in the coolant that have found their way there via a blown head gasket.

But before you go tearing into the engine, check the service records to find out how old the coolant is. Coolant will discolour over time and kilometres and what you’re seeing as a `milky colour’ might simply be old coolant that has gone cloudy and needs changing.

These cars used a fairly simply check-valve on the fuel pump to prevent fuel draining back into the tank when the car was parked. As the car ages, this valve wears to the point where it won’t maintain fuel in the lines going to the engine. If that happens, it will take some time and cranking to get fuel from the tank to the engine. This is the delay you’re experiencing.

The worn valve is only allowing a small amount of fuel to drain back which is why you need to wait six hours or so for the problem to show up. A new fuel pump will fix it.

It’s common practice to replace the water pump at the same time the timing belt is changed because they usually need it. It doesn’t appear to be overheating, i.e. the gauge is not going off the scale, so I would just keep an eye on it and if it does show signs of overheating get it checked out.

You probably could, but before you commit I would line them up to make sure the 2006 alternator would fit the later model. If they do, and I expect they will, you should be okay.

A ticking noise is often a sign of a problem with the starter solenoid. If it were the neutral start/safety switch, you wouldn't hear anything because there would no power getting to the starter.