Citroen C4 Cactus Alternator

The unit itself runs R2,400-R6,550 for the common models — C3, C5 Aircross, Xsara — with fitting of R800-R1,600 depending on how accessible it is. Quality aftermarket units from the established manufacturers are good value and widely stocked here. Reconditioned units are also a legitimate route on an older car, provided the rebuilder warranties the work. Higher-output alternators, which the diesels tend to carry, sit at the top of the range.

Roughly 100,000-150,000 km, or five to seven years, in easy use. Short trips shorten that because the alternator spends its whole life recharging and never gets to coast. So does sustained heat — Limpopo and Mpumalanga summers are hard on the rectifier and the regulator — and so does dust, which kills bearings. Keeping the auxiliary belt correctly tensioned is the one piece of maintenance that genuinely extends alternator life, because a slipping belt makes the unit work harder for less output.

Only as far as the nearest workshop, and only if it has partly failed rather than stopped. Once the alternator is not charging, you are running on stored battery capacity, and that gives you perhaps 30-60 minutes before the engine cuts. If you have to move the car, switch off the aircon, the radio and anything else you can live without, and go straight there. Running the battery flat repeatedly also damages the battery, so the cheap decision quickly stops being cheap.

Bearings wearing out with age is the most common, followed by the voltage regulator, which is the electronic part and dislikes both heat and voltage spikes. Then there are the avoidable causes: a slipping or perished belt, water thrown up through deep standing water and dust drawn into the housing. Local conditions push the last two harder than most markets. On the turbocharged THP and the HDi diesels there is more electrical load overall, which gives an ageing alternator less margin before it starts causing symptoms elsewhere.

A multimeter across the battery terminals answers it in a minute. Engine off, expect around 12.6 volts. Engine running, you should see 13.8-14.4 volts. Now switch on the headlights, the blower and the aircon — the reading should hold above 13.5 volts. If it sags toward battery voltage under load, the alternator is not keeping up. Any competent independent workshop, or the AA at the roadside, can do this test, and it is worth doing before anyone quotes you for a new battery.