Fiat MultiJet (badge, not an engine)

MultiJet is a badge, not an engine. Fiat applies it to any of its common-rail diesels, and this catalogue's rows show it spanning 1.3 to 3.0 litres across Fiat, Jeep, Lancia, Opel, Suzuki and Tata.

The 1.3 is the one most people mean, and it is a genuinely notable engine: the Small Diesel Engine, built in enormous numbers and licensed to Suzuki, Opel and Tata — which is why a Suzuki Swift and a Vauxhall Corsa can have a Fiat engine and neither car says so.

But a 3.0 MultiJet in a Ducato shares nothing with it, and the badge does not distinguish them. Establish the displacement first.

Two faults recur on the small MultiJets and are worth knowing:

• The swirl-flap actuator and the inlet manifold, where carbon build-up jams the flaps and the motor strips itself. The symptom is a limp mode and a fault code naming the manifold, and it is a manifold job rather than an engine one.
• The injectors, which are Bosch or Denso depending on the year, and whose failure gives a knock at idle, hard starting, and a fuel-return imbalance measurable without removing anything. A leaking injector seal also lets combustion gases into the head recess and welds the injector in place — which turns a cheap job into a very expensive one, and is the argument for acting early.

Its EGR and DPF behaviour is the ordinary small-diesel story, and short journeys are what ruin both.