Citroen C4 Aircross Fuel Pumps

The two types are far apart. An in-tank electric pump for a petrol C3 or Xsara is R2,500 to R5,500, with R1,200-R2,100 to fit it — usually through an access hatch under the rear seat, occasionally by dropping the tank. A high-pressure pump for an HDi diesel is R7,600 to R17,300 before fitting. Given that gap, it is worth being certain which pump has actually failed before ordering, and a fuel pressure test rather than a guess is what settles it.

Running the tank low is the habit that does the most damage to in-tank pumps, because the fuel is what keeps them cool. After that: a clogged filter making the pump work against restriction, contaminated or watered fuel from an unreliable forecourt, and corroded wiring or relay contacts that starve the pump of voltage. On the diesels, water in the fuel is the specific killer of the high-pressure pump. Changing the fuel filter every 40,000-60,000 km, and draining the water trap on a diesel when the light asks, is cheap insurance against a very expensive part.

It is a bad gamble. A pump that is intermittent today fails completely without notice, and it tends to do it under load — which means a lane on the N1 rather than a driveway. There is a mechanical argument too: low fuel pressure leans the mixture out, and a lean-running engine puts heat into the pistons and the catalytic converter. On a THP or HDi that turns a fuel pump bill into an engine bill. Get it tested rather than nursed.

In-tank electric pumps commonly reach 150,000-250,000 km and quite often go the life of the car. High-pressure diesel pumps work far harder mechanically and are more sensitive to what passes through them, so their life is decided by filtration and fuel quality rather than by mileage. The pattern we see is that pumps in cars with a documented filter history last; pumps in cars where the filter has been skipped fail early, and usually take an injector or two with them.

Always. A blocked filter is frequently what killed the old pump, so leaving it in place puts the new one under the same load from day one. Do the strainer sock on the in-tank assembly at the same time — it is a small part, it comes with most pump kits, and replacing it means the sediment already in the tank does not go straight through your new pump. Together the filter and strainer add R250-R850 depending on the model, which is trivial next to what you have just spent.