Hi, My car is 2007 Focus 1.6TDCI. Recently, I am hearing a whining noise. It sounds to me like to could be coming from the alternator belt or a bearing. The belt itself seems fine though. I am also smelling a sort of burning smell from under the bonnet. It has also reduced massively in fuel economy, down to 30-35mpg from 45mpg.

I had heard it a bit last week and then it went away. I also made a oil change, using the proper grade of oil (Castro, full synthetic, low sap for diesels) during the weekend.

I started hearing it again yesterday morning. I went to the mechanic this evening and said he could hear the start of a bearing failing but it should not affect fuel economy that much.

I have a lot of driving (200miles+, around town mainly) to do next Sunday and was worried if it would be safe to use it...

Please help!
Thanks a lot, Mark

Hi Mark

Not sure what your mechanic advised but I wouldnt use the car anymore as if something is seizing it could cause a lot of damage.
Are you able to remove the alternator belt yourself if so take it off and make sure it out the way and start the engine for a short period and see if your noise goes away.If it does you know one of the pullies run by the belt is at fault.WITH THE ENGINE OFF see if you can turn them as fast as possible by hand and listen for grumbling and a roughness feel from the pulley.If it turns out not to be any of these items then it will inside the timing case which is even more reason to not drive anymore .See how it goes Paul

Hi, thanks for your reply. Mechanic said that it should not be anything serious. But can the sudden loss in fuel economy really be related to this or is it something else?

id say a burning smell poor economy and an engine whine was serious if its a belt rubbing it will melt and snap depending on which belt could cause damage to the engine or wiring or leave you stranded.
is the economy linked without proper diagnosis its anyones guess. if its a bearing which one timing belt tensioner alternator water pump try a different mechanic as thats a poor diagnosis and without knowing how can he determine if its serious.
last time a mechanic said that my mates dads transit went up in flames as he was driving. better safe than sorry mate

Slipping clutch? That might explain the plummeting fuel economy...

Hi Yes Clutch slip is a good shout are you able to determine the revs are higher than normal especially when loaded up a hill .Can you confirm the noise and burning smell is when you are driving or when stationary ?.If its when driving it could be brakes seizing and a wheel bearing !If the noise is when engine running before you drive anywhere then back to my earlier advice re a seizing pump,pulley,tensioner area

I've burnt out a couple of clutches in my time and they always seemed to smell of overcooked fish.

Hey guys, first of all, THANKS A LOT for the replies!! much appreciated!!

An update: Basically Saturday evening the noise went a way all of a sudden, apart from a very slight bearing whine which I can only hear sometimes and when Im looking for. On Sunday (yesterday) we spent the day going around in it, did around 160km with four people on board, mostly around town with the a/c on and a lot of vigorous acceleration and I managed to average 36mpg which I think is very good for the type of driving I was doing. This morning on my way work with some traffic but much calmer driving style I managed about 50mpg - so fuel economy is back as well!!

So, all of a sudden the problem seems to have gone away since there was also no burning smell at all. Called the mechanic today and he said that he wont be able to spot the problem since the noise is now gone. He said that probably there is a bearing which is starting to fail and maybe there was some dirt which was causing the noise/smell. I think this mechanic is quite ok and has a lot of experience on Peugeot/Citroen/Ford engines (he is always working on a Peugeot or a Mini One or a Ford when I go to see him). Finally he told me that best thing is that if the noise is back I take it immediately to him.

I had gone to another mechanic (I do not think hes as keen on these engine as the other - used to go to him when I had a Toyota) and told be that its probably the alternator needing a new bearing or a service so advised me to take it to an electrician.

By the way clutch feels fine. The noise I believe was coming from the engine since I can hear it even when stationary. It become louder when I rev the engine. Turning on or off the a/c does not make any difference.

So conclusion: should I wait for the noise to become more noticeable or should I seek a third mechanic?

ide wait since its gone you will find they will all say the same as the first mechanic there is an alternative that you had the bearing noise but the brakes were perhaps sticking slightly which will effect the fuel economy and create the smell now they have freed off all is fine or a build up of soot in the exhaust just leave it and take the first guys advice