Toyota AD (1AD / 2AD)
inline-4 · turbocharged · diesel · 2005–present
Also known as: 1ad-ftv, 2ad-ftv, 2ad-fhv, 1ad, 2ad, 2.2 d-4d, 2.0 d-4d ad
Toyota's 2.0 and 2.2 common-rail diesel — the 1AD and 2AD — in the Avensis, Auris, RAV4 and Corolla Verso.
⚑ This family has the worst reputation of any modern Toyota engine, and saying so is more useful than a generic fault list. Cylinder head cracking and head gasket failure are a documented pattern on the 2AD-FHV in particular — Toyota extended warranties over it — and the symptom is coolant loss with no external leak, later pressure in the header tank.
The injectors are the second known item and their failure is cylinder-specific and code-setting. Injector seals leak combustion gases up around the injector body, which carbons the seat and makes removal a job in itself.
The particulate filter is where most running complaints originate, and the duty cycle that breaks it is short urban journeys: the filter never reaches temperature, and a rising oil level on the dipstick is fuel dilution rather than a servicing error.
The later 1WW, 2WW and 1GD engines replaced it and share almost nothing with it, which is worth establishing before applying anything written about a Toyota diesel.
Cars fitted with this engine
4 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.
Lexus
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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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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