My 1.4mpi has resently developed a rattle from the engine bay, and I have isolated it to the oil filler cap. the rattle is only audible for five minutes after first startup with a cold engine. The cap seems to rotat freely and isnt attached in any way. Does anyone know how the closingmechanism is constucted? The plastic cover on top of my engine is long gone, and the spare cap i understand would be located underneath it is gone withe it

The cap closes on the cover, the spare cap is a different design and is there to be used when running the engine without the cover. You can either get an engine cover and use the existing cap or get a cap and seal of the same design as the spare cap, this is identical to the Felicia/Favorit 1.3 item and should cost less than £5.