With so many cars these days having ‘extended’ recommended service intervals, it can be easy to assume that a vehicle’s maintenance requirements can safely be ignored, yet expect it to still carry on functioning regardless…
Well this is not the case, as highlighted by a cautionary tale sent to me by diagnostic specialist Edward Haggar (and thanks Edward for bringing this to our readers’ attention).
The accompanying pictures were taken on a 2016 Vauxhall Adam 1.2. Unfortunately the car’s owner had allowed the car to run past Vauxhall’s recommended service interval, thereby invalidating the warranty.
The Vauxhall had only covered 18,000 miles from new, but occasionally the engine management system light would flash and the engine would misfire.
Edward carried out a diagnostic check (i.e. plugging in diagnostic equipment, which ‘interrogates’ the vehicle’s management system via the diagnostic socket), revealing that the fault code ‘P0304’ had been stored in the car’s Electronic Control Unit (ECU). This in turn indicated a misfire on cylinder No. 4.
So Edward’s first port of call in tracing the root cause of the trouble was to remove the ignition coil pack and to check the spark plugs. As indicated in the photographs, water ingress can clearly be seen in the vicinity of cylinder No. 4, affecting the coil pack and the spark plug (which sits within a deep well), causing a misfire.Although the car’s warranty had been invalidated, as mentioned, in this case its owner was fortunate that no serious damage had been done, and rectification costs were not too expensive. A set of new spark plugs, plus a clean-up of the coil pack and the application of protective rubber grease around the coil rubbers, sorted out the trouble.
However, modern cars in general are very intolerant of being operated past the scheduled service intervals, not least because these are set at very long intervals to start with.
Edward’s strong recommendation with all modern vehicles, is to err on the side of caution and to have it serviced at least twice as often as the service schedule indicates. In other words, if, say, the recommended service interval is every 15,000 miles or annually (whichever comes first), it is preferable to have this attention carried out every 7,500 miles or every six months.
It’s worth mentioning that this is especially important for engine oil and filter changes. Modern engines have close tolerances and are highly efficient, but in order to operate effectively and to provide reliable running for the long term, they rely on clean engine oil of precisely the correct viscosity rating and quality, as advised by the vehicle manufacturer. This applies to any power unit, but is especially true of any turbocharged engine (the oil has to lubricate the turbocharger bearings, often coping with rotational speeds of well over 100,000 rpm), and those with variable valve timing/control systems that rely on clean oil in order to function properly.
In the case of this Vauxhall Adam, if the car had been serviced at the manufacturer’s designated intervals, the ignition problem would have been picked up earlier, before it developed and the symptoms worsened.