Hi there welcome to just answer hope i can be of some assistance to your problem i just need a few more details regarding your fault.
The noise that you hear in the engine compartment when the engine is switched off how long does it last for?
Dose this noise sound a bit like a scraping noise?
When the engine revs on its own does it rev up to around 1000 - 1500 rpm for a few seconds when idling then comes back down?
Did the garage do anything to try and fix the fault or was the vehicle just put on a diagnostic machine to check for codes?
when your vehicle is idling does it run a little rough and feel like it misfires a bit?
Can i have your reg to check on the history and see what has been done on your vehicle?
Noise lasts for 1-2 minutes
A whining/whistling noise, no scraping
Just goes up slightly, not as much as 1000rpm, then back to idling within a few seconds.
Just for codes as far as I'm aware.
Yes, runs a bit rough, misfires and tends to 'surge'
Also - when cold in the morning, at 1500 revs it feels as though it wants 'to go' but doesn't!, it sort of 'dies', give it a bit more throttle then it picks up and goes.
Hope this helps. Thank you!
Thank you for your information your reg will not go in as it is a private plate could you possible get me the chassis number?
Ok then in regards XXXXX XXXXX noise that you are getting i can not realy help with that as it is difficult to say with out hearing the noise, these vehicles did have faults with EGRs failing causing noises but these would only last for around 1-3 seconds after the engine was switched off.
In regards XXXXX XXXXX other running issues the problem that you are getting is a common problem and there are two ways of fixing the fault, now one it to reprogramme the engine managment unit with a later level software version and this somteimes fixes the problem how ever i can see that this was done on the 7/12/2010 so i can only assume that this has not cured the problem and nothing was done on the 13/12/2010 jsut a check for codes.
Now what i normally do to fix these problems is to install a new inlet metering valve on the fuel pump as this is what controls fuel pressure hence why you get rough running and surging etc as the fueling is not been controled correctly also these do ware over time and i see that your vehicle has done just over 85000miles.
once this is done all the injectors pump learn and injector pilot learn need to be reset but alot of dealers do not bother to reset these as they can be difficult to do but it needs to be done to cure these problems.
Hope this helps you with your problem sorry i can not shed any light on your noise but these can be difficult without hearing.