Nissan TD27 / QD32 / ZD30

Nissan's commercial diesels — the TD27, QD32 and ZD30 — in the Navara, Terrano, Patrol and Urvan.

The TD and QD are indirect-injection with mechanical pumps and have the durability that implies: slow, unstressed, and repairable far from a dealer. The ZD30 is direct-injection and is a different engine to diagnose despite sitting in the same vehicles.

⚑ The ZD30's reputation is the thing to know. In its earlier electronically-controlled form it has a well-documented pattern of melted or holed pistons, and the accepted causes are boost and fuelling drifting out of specification — a sticking variable-geometry turbocharger, a blocked intercooler, or an EGR left to carbon up. On a Patrol or Navara with one, boost and exhaust temperature are not routine checks.

On the TD and QD the recurring items are old-diesel wear: glow plugs, injection pump timing that drifts with the belt, and injector nozzles that carbon up and knock at idle.

The YD25 that succeeded them is common-rail and has its own page here.