Toyota 1AR-FE

Toyota's 2.7-litre four — the largest member of the AR family — in the RAV4, Highlander, Sienna and Venza, and in the Tacoma and Hilux under the 2TR name it shares nothing with.

Its point is torque without a V6, and that is the whole reason it exists: it is a big-displacement four in vehicles that would otherwise need six cylinders, which makes it heavier on fuel than the 2.5 2AR beside it and considerably cheaper to keep than the 2GR V6 above it.

Its faults are the AR family's and are ordinary. The water pump weeps rather than fails outright, so a coolant smell with no puddle is worth tracing there first; ignition coils go one at a time and give a misfire under load; and at high mileage some engines use oil through the rings. An engine using oil is not necessarily worn out — the level matters more than the cause on a car of that age.

⚑ Do not carry the 2AZ reputation across to it. The 2AZ's oil consumption and stripped head-bolt threads are the first results any search for a Toyota four of this size returns, and neither is an AR pattern — the AR family was designed to end them. Confirm the code on the block before repeating that history to an owner.

The 2.5 2AR and the 2.0/2.5 5AR/6AR have their own pages here, and the extra letters are the only place the difference is written down.