zanussi oven

Hi, I tried changing the fan oven element but that has not fixed the problem, any advice on further action? Some other posts I’ve seen suggest it could be the fan motor itself that’s causing it to trip.

We have a zanussi double oven ZOD 350X and the main fan oven is not reaching/holding the correct temperature. I've changed the element and also the thermostat but it's still the same. I'm not 100% sure that the fan is working properly but didn't think that would stop the oven reaching...