Hi there newbie here, at first during wet and damp conditions, my fan belt would make a squeely squeeky noise and when after driving it would quieten down. It did it again the other day but after a while the sound changed and I can't seem to figure out where it is coming from. My timing belt was changed last year and I have covered around 6k miles since then. I usually get around 60 odd mpg but recently on a long journey, or even shorter ones it has dropped about 10 mpg. Also this noise appears while driving after certain revs. My friend reckons there is an air leak or something near the Turbo. I have no excessive smoke coming from the back, as I have read the horror stories and the Turbo is kicking in, plus it does not look that old, maybe it was replaced before I had the car. But my friend thinks it's loosing power or not reaching it's peak but it's hard to tell with the noise we can here while driving, I also need to change the front wheel bearings, by the way can I do this my self, im a novice who sometimes likes to have a go.

Anyway back to the noise, it is hard to describe sort of a vrrrrrrrrrrrrm and then fades at lower revs. I had the erg valve cleaned last year as my car lost power and spewed out black smoke. I have also changed the oil and filter my self a year ago after it was cleaned, I asked Renaultabout the recommended oil and they said any semi-sympathetic would do, I decided to go to GSF and get car lube as they said it was a goodoil. Followed by top ups with fully sympathetic, Renault actually told me I did not need it. Well anyway apart from replacing the fuel filter in which I intend to do, I have took note of the horror stories about turbos on the forums. Basically could it be the turbo on it's way out, is there anyway of telling. I do have oil around that area but I also over spilt oil while topping up. Could it be the ERG valve, the belt or something totally different? I have limited funds is it worth me buying a warranty in the hope of them fixing it. I can record the noise if need be. My friend who knows more about cars than me said it not the actual turbo but more like a leak.