Last week, Ford Motor Company of Southern Africa announced that it would finally implement a two-stage recall of certain Ford Kuga models due to a fire risk, with some 4 556 examples of the 1,6-litre model affected.

But many South Africans have asked whether the 1,5-litre engine (which replaced the 1,6-litre locally) is susceptible to the same issue. Indeed, it's a question that has been trending on social media so we thought it best to investigate the key differences between the two engines. We have laid out these differences in the table below.

Component

1,6-litre EcoBoost engine

1,5-litre EcoBoost engine

Exhaust manifold

External bolt-on

Integrated into head

Water pump

Fixed ratio belt-driven

ECU-controlled clutch on belt drive

Intercooler

Air-to-air

Water-to-air

Discussion

The difference in the head design between the 1,6-litre and the 1,5-litre (integrated exhaust manifold) may be the latter's saving grace in the Kuga fire saga. According to Ford SA, the failure mechanism of the 1,6-litre engine is a cracked cylinder head, resulting in oil reaching the hot exhaust manifold. Hypothetically speaking, even if the 1,5-litre engine's head were to crack, the failure should be different to the 1,6-litre engine – hopefully the oil would not leak out onto the exhaust manifold with this design.

The water pump change is interesting as Ford SA mentioned a lack of coolant flow rate as a contributor to the cylinder head cracking failure mechanism. The 1,5-litre engine can vary the coolant flow rate thanks to a clutch connected to the belt drive and controlled by the engine control unit (ECU). This is actually to reduce warm-up time by disconnecting the water pump for a short period after start-up. It may just offer a higher cooling flow rate when engaged.

The water-to-air intercooler (cooling the intake air) was introduced to up the efficiency of the engine and should not have an impact on the fire safety discussion.

Background

The 1,6-litre, four-cylinder EcoBoost engine was launched in 2010 as part of the first-generation EcoBoost turbopetrol range. The inline four-cylinder (I4) design is applied to the 2,0-litre Ecoboost as well. The all-aluminium-alloy block and cylinder head engine was Ford's first stab at the downsized petrol engine.

The award-winning 1,0-litre, three-cylinder EcoBoost engine was launched in 2012 and featured many additional technologies, such as the integrated exhaust manifold in the cylinder head. This is important because this technology was transferred to the 1,5-litre EcoBoost engine when it was launched in 2014 to replace the 1,6-litre EcoBoost.

The main reason for the replacement was reportedly the tax break offered by certain markets (chiefly China) for vehicles fitted with engines smaller than 1,5 litres.

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