Ford Fiesta - Rattling from engine

[JayLaw]

Hello, 

I'm driving a 2013 MK7 Ford Fiesta. I've not had any issues with it until yesterday. I've driven it right down to the last drop of fuel, filled up with E10 petrol for the first time, driven a few miles and the check engine light has come on. 

I've checked under the bonnet with the engine running and there seems be a loud rattling sound coming from the fan belt / alternator. Never had an issue before. Is it just a coincidence it happened after an E10 fill up? Is my car knackered? 

[Theshed]

Highly unlikely to be a result of the e10. Possibly picked up some debris from tank if you have let it run really low.

I would start by turning engine off and feel around fan belt area. Try and wiggle the belt and listen/ feel for anything loose, like a bearing in alternator.