Ford Nano (2.7/3.0 EcoBoost V6)

Ford's compact twin-turbocharged V6, built in 2.7 and 3.0 litre forms — so the displacement is a property of the variant rather than of the family, and the 2.7 of an F-150 and the 3.0 of an Aviator are the same engine at two sizes.

It is unusual enough mechanically to be worth knowing before diagnosing one: the block is a compacted graphite iron core with an aluminium ladder frame bolted around it, which is why an engine of this output is physically small enough to sit where a four-cylinder would. It matters at the bench rather than at the roadside, but it changes what a rebuild costs.

The valve alloy is the fault that defines this family and it is not a wear item. Pre-2021 engines were built with intake valves whose alloy could crack and break up, and a broken valve destroys the cylinder it is in. It presents as a sudden misfire with no gentle build-up — so on an affected-era engine, a single-cylinder misfire deserves a compression or borescope check before anything is thrown at the coil and plug. Ford's own remedy was a redesign, not a service procedure.

The rest is the modern direct-injection list, and it reads the same way on every engine in this catalogue that carries it:

• Intake-valve carbon, because port fuel never washes the back of the valve. Later engines add port injection alongside direct and largely stop accumulating it.
• Ignition parts as a consumable at shorter intervals than the schedule suggests — boost pressure is hard on plug gaps, and a tired coil on a twin-turbo six shows up as a stumble under load long before it does at idle.
• Plastic oil-pan sealing on early production, which weeps rather than fails.