Autoelectro debunks winter misconceptions about starter motor and alternators
After serving the automotive aftermarket for nearly 40 years and supporting it through many tough winters, Autoelectro has nearly heard and seen it all when it comes to starter motors and alternators. Here, Harnek Bhogal dispels winter-related myths that are a timely boost ahead of the winter season.
Myth: The cold weather causes the failure of an alternator and need for it to be replaced
Truth: It’s a ‘chicken and egg’ situation; the cold weather is not the direct cause for the premature failure of an alternator, but, rather, it is the increased electrical load that often leads to premature failure.
As temperatures drop, motorists switch on their headlights more frequently, wiper blades work harder, windscreens and seats are heated – all of these increase the load on the alternator. A weak or substandard alternator is unlikely to cope with this demand and will fail.
As the alternator increases its workload – overworking itself – it may become extremely hot, which can put strain on the internal components.
Myth: Cold starting or slow ‘turning over’ is down to the starter motor
Truth: The reality is that this could be because of a number factors – but, most likely, it is the state of the battery. An inadequate battery condition is unlikely to deliver enough current to the starter to start the engine. This can often be incorrectly diagnosed as a faulty starter motor.
If a replacement starter motor is installed, fitted next to the inefficient battery, the same issue will arise: not enough current being delivered to the starter motor. It will be forced to work harder than it should to ‘turn the engine over’, which can cause the starter motor to burn out. This is when the internal components of the starter – brush holder, armature etc – all overheat and fail. Once a starter motor is burnt out, not only will it not work, but it is vital that the root cause of the problem is diagnosed.
If the battery was changed in the first instance, the vehicle may not have even needed a new starter motor – creating unnecessary cost, labour, frustration and repair.
For technicians, they should recongise that a starter motor does not generate any power on its own – so wouldn’t burn itself out. Distinct symptoms, like distinct burning or a blue colour on the pinion shaft, indicate that something on the vehicle has caused the premature failure of the starter motor, and failure to rectify this fault will likely lead to it happening again.
Myth: Anyone can use a jump starter!
Truth: Simply, the incorrect use of a jump starter can cause significant damage to a vehicle’s electrics and charging systems.
Jump starting a vehicle can trigger a sudden voltage surge that has the potential to cause serious electrical faults and, even, damage the alternator. Putting excessive pressure on the regulator – the component inside the alternator that is responsible for keeping the voltage stable – the ECU and other sensors/modules can cause disaster.
At Autoelectro, we were told that a Lamborghini had been jump started incorrectly, killing all the electrics on the vehicle, leading to a bill in the tens of thousands of pounds from the main dealer to repair it.
Best practice and preventative care crucial
By dispelling these myths, Autoelectro hopes that motor factors and technicians alike can apply best practice and preventative care before winter takes hold – to ensure parts and electrics come through the cold period unscathed.
Best practice involves checking the belt for cracks, breaks or damage, and checking that the tensioner is in good order too. A damaged or broken belt is prone to slipping on the pulley, reducing the level of friction and leading to intermittent charging issues.
This also includes making sure electrical connections, most often B+ terminals, are kept clean and corrosion free. If there is moisture or condensation within the engine, this can drip onto the terminals and can arc/spark when the terminal is live and energised, leaving the potential for heat damage to the terminal.