Land Rover Td5

Land Rover's 2.5 five-cylinder diesel — the Td5 — in the Defender and Discovery 2.

It is an electronic unit-injector engine, which is the distinction that decides its diagnosis: each injector contains its own pump, driven off a camshaft lobe and fired electrically. There is no injection pump and no rail pressure to read.

⚑ Its defining fault is the injector wiring harness. The loom runs under the rocker cover through an oil-tight connector, and oil wicks up the wires into the ECU. The symptoms are erratic — misfires, poor starting, injector codes that move between cylinders — and the repair is a harness and connector rather than injectors, which is what people replace first.

The oil pump drive is the other known item, and its failure is total: the pump is driven by a chain from the crankshaft, and a worn drive gear loses oil pressure without warning. On a high-mileage Td5 it is a standard inspection, not an exotic one.

There is no particulate filter and no EGR cooler to speak of, so the modern diesel fault list barely applies — which is a large part of why these are still working.