Fiat has to stop making Punto and Idea models for four days because of a supply glitch at the plant building its top-selling Multijet diesel engine.

“The supplier of an important component for the Multijet provided a faulty lot so we have had to suspend production (of the engine),” a Fiat spokesman told Reuters, adding: “We have made up for the lack of diesel motors by finishing orders for cars with petrol engines but it’s impossible to do that any more because there’s such demand for diesel.”

The report said the Multijet engine – made in Poland with industrial partner General Motors – is key to Fiat carving out a space in the increasingly popular diesel market which now accounts for about 55% of Italian car sales.

Reuters said the stoppage will hit 3,500 workers at Fiat’s Mirafiori plant in Turin between April 13 and 16, effectively extending the Easter break by a week.