AJD-V6 3.0 D

Warning light, limp mode, oil level rising above the maximum mark from fuel dilution. The filter needs sustained hot running to regenerate. A car used for short urban trips never completes a regeneration cycle.

Check: Read the DPF soot load and the distance since the last regeneration on a scan tool, and check the engine oil level and smell it for diesel. Ask what the car was used for. A short-trip city diesel is the wrong car regardless of mileage.

A knock or rumble from the front of the engine, a wobbling pulley, and belt squeal or a lost belt once it separates. The pulley is a bonded damper and its rubber layer degrades, letting the outer ring move on the hub. If it comes apart it takes the belt and can damage the front of the engine.

Check: With the engine running, look at the crankshaft pulley for any wobble in the outer ring. It's a five-minute check and it's the one Jaguar-specific item on this engine.

Coolant loss with no visible external leak, white smoke, sweet smell. The EGR cooler cracks internally and leaks coolant into the intake. BMW recalled affected diesels over a fire risk from glycol deposits igniting.

Check: Check coolant level and look for unexplained top-ups in the service history. Verify the recall was carried out. It's free and searchable by VIN.

Often none until it happens. Rough running, then in the worst case an engine destroyed by an ingested flap. The intake manifold's swirl flaps run on spindles that wear. A detached flap can be drawn into a cylinder.

Check: Not visible without removing the manifold. Ask whether the flaps have been removed or the manifold replaced. Many well-kept examples have had this done preventively, and that's a selling point.