Isuzu RZ4E-TC / RZ4F-TC

1.9 L · inline-4 · turbocharged · diesel · 2017–present

Also known as: rz4e, rz4e-tc, rz4f-tc, rz4f, isuzu 1.9 ddi

Isuzu's 1.9 diesel — in the current D-Max and MU-X.

It replaced a 2.5 with a smaller, lighter engine making similar output, which is the design and also the source of every argument about it: a 1.9 in a one-tonne pickup works harder than the 2.5 it replaced, and owners who tow notice.

Its faults are the modern-diesel set and the usage pattern decides them. The DPF on a vehicle used for short journeys is the commonest complaint, and Isuzu's regeneration is sensitive to being interrupted — an oil level rising on the dipstick is fuel dilution from cut-short regenerations, and it is the warning that matters most because diluted oil is what damages the bearings.

The EGR cooler and the intake carbon follow the same pattern and for the same reason.

The RZ4F-TC is the higher-output version in the later vehicles; mechanically the same engine, and the letter is the only place the difference is recorded.

Cars fitted with this engine

5 generations, across 2 makes. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.

Isuzu

Mazda

BT-50 TF 2020–present

Information, not instruction

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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

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