2002 Mazda Premacy Pricing and Specs

It all depends of what sort of a leak we’re talking about here. If the tank is constantly leaking after it’s been filled up, there’s clearly some sort of hole somewhere in the tank or its plumbing from the filler neck to the tank proper. You could surmise that the level of fuel in the tank at which the leak stops, is also the level of the hole or crack. As the fuel drains further (as you drive the car) the fuel level is below that of the leak-point and the leak stops. Either way, this is a dangerous situation as even if there’s no liquid fuel leaking, there’s almost certainly fuel vapour escaping (which is more flammable than petrol itself).

While it’s rare for a tank to fail, much more common is having the plumbing which takes the fuel from the filler neck to the tank cause a leak. But if the leak stops soon after you’ve filled up, it could simply be that a small amount of fuel has sloshed out of the filler neck and into the car’s body near the neck, where it can drain away, thanks to gravity, towards the bottom of the car where you’re seeing it. Next time you fill up, be sure not to overfill the tank and remember to use the watering can on hand to slosh away any spilled or excess fuel.

In the old days, this would (probably) have been a simple matter of a faulty wiper switch. But on modern cars, functions like the wipers are controlled by a computer called the body-control module. If this starts to fail it can send odd signals to the various things it controls (wipers, lights, central locking, climate-control, entertainment systems and many more).

An automotive electrician might be able to pin-point the problem, and that’s a good place to start. But before you do that, try this: Disconnect the car’s battery and leave it overnight. When you reconnect the battery, you might just find the computer has reset itself and things return to normal. It can sometimes be just a temporary fix, but it’s definitely worth a try. And it’s free.

There’s a very simple check you can do to see whether the battery or the charging system (alternator, regulator and wiring) is at fault here. With the engine running, place the probes of a multi-meter (switched to measure voltage) on the relevant battery terminals. If you see a figure of anywhere between 13.2 and 14.7 volts, the charging system is doing its job. You might need to rev the engine slightly off idle to see these numbers, but the voltage going into the battery should be in that range.

At this point, the battery becomes the main suspect, and a worn out battery will often neither hold a charge nor accept one.