There was a squeal from an engine belt in my Fiesta in every gear while accelerating.  When at speed or coasting it was gone, only when under load. 

I brought it to my Ford garage and they replaced an idler pulley after saying the belt was twisted.  But I have just driven the car for the first time since the work today and the squeal is still there !!!

it has to go back at the end of the month for a new starter motor but what could the squeal be ? Getting fed up with a branded garage not being able to identify and fix the problem.  
 

C

 

The usual thing to change first (unless there is clear evidence of a faulty part) would be the auxiliary drive belt, in the good old days refereed to as the 'fan belt'

 

They may well propose to change that next.  The sound is not as loud as last time but it’s there.  I’ll have to let them know at the end of the month.  More expense.  Thanks. 

A little talcum powder on the poly V side of the belt usually stops the squeal temporarily as a confirmation test.

i did have a belt installed out of line on the crank pulley by one V groove but this squeaked from start up.

Surely they fitted a new belt at the same time as the new idler?  It should be itemised on the receipt if it's a Ford dealership.

11 minutes ago, TomsFocus said:

Surely they fitted a new belt at the same time as the new idler?  It should be itemised on the receipt if it's a Ford dealership.

Don’t think so.  Just says ‘idle - pulley’ plus labour.  

2 minutes ago, Charlotte Darcy said:

Don’t think so.  Just says ‘idle - pulley’ plus labour.  

Very strange.  The belts generally cost less than £10 so not worth refitting an old one.

Which engine is it?

51 minutes ago, TomsFocus said:

Very strange.  The belts generally cost less than £10 so not worth refitting an old one.

Which engine is it?

1.25 petrol. 2010 car. 

Is it the belt slip? You can usually get fan belt squeal blipping the accelerator in neutral from start up due to alternator load etc. Talc on the belt would stop the squeal temporarily as a check.

Assuming you haven’t heard it with the bonnet open, ie only when moving, can you be sure it’s belt noise.

is there a possibility it could be clutch slip or engine rock causing something to rub?

just ‘brainstorming’

12 hours ago, Charlotte Darcy said:

1.25 petrol. 2010 car. 

Is it a non-air con model?  The only idler I can see for that engine is in place of the air con pump for the non-AC models.

This should be the genuine belt (£20) - Genuine Ford Fiesta Mk7 Mk8 1.2 1.4 1.6 16v Drive Belt V-Ribbed 1830909 | eBay

But you can buy good quality aftermarkets such as this one for £12 - Gates Alternator Fan Drive Belt For Ford Mazda 6PK1019SF | eBay

Without wishing to sound patronising, swapping the aux belt is a job that I believe you're more than capable of doing yourself.  Don't necessarily need to pay garage labour.  As above though, it's worth making sure it is the belt causing the noise.  You can even briefly run the engine without the aux belt fitted as a test.  If the noise is still there, you know it's not the belt or any of the pulleys.

This is the belt run for a non-AC 1.25 Mk7.  It's a stretch belt so doesn't have a tensioner fitted.

Crankshaft - Waterpump - Alternator - Idler Pulley

Hi.  Thanks for all the responses.  I opened the bonnet for a look and I can see a new pulley and what looks like a new belt.  See photos.  

Yes, that belt does look new.  

The water pump pulley looks very shiny so the belt could be slipping on that.  They start fully painted black but the paint does wear off over time.

Just had my car in the garage to get a new starter motor and I asked them to look at the squeal noise.  It’s there sometimes starting up when under load but seems to get less as the belt warms up if I drive on the motorway for example.  
 

Anyway they took it for a spin and double checked everything and can find nothing wrong, rather annoyingly.  I bet when I collect it the sound will be there.  Is this something unique to fiestas and just something I have to live with especially as nothing mechanical is wrong. 
 

I also asked them to have a Quick Look at the front suspension as it’s a bit rattley and soft but they say it’s ok too.  I was hoping there might be wear and tear to explain it but they say it’s ok.  However I do know I have to get it tracked/aligned so that might help but I do find the car seems to feel every bump so I had hoped the springs might have been in need of replacement.  Again is this a common fiesta thing ??? 

Just be aware that if you take it to one of those 'quick repair' outfits they're bound to find something that needs  changing!

1 hour ago, Charlotte Darcy said:

Is this something unique to fiestas and just something I have to live with

Neither is the answer 😀

It's not limited to just Fiesta's and it's not something you have to live with.

Just get a new auxiliary drive belt fitted and possibly the belt idler tensioner pulley (if fitted). A simple and easy repair that will not cost very much.

Hi.  They did that last time.  Something suggested here was that the water pump pulley, which is now shiny with age, might have been the issue but don’t think the garage were bothered or didn’t say it might be the issue.  
 

And yes, your right, if I bring it to a third party place they are bound to recommend everything gets changed, probably for no reason, hence I was sticking to the Ford garage.  Alas. 

in that case I would think you need a new water pump. On a 2010 vehicle they would normally have been changed as a matter of course at the same time the cambelt was changed when the car was 10 years old.

If the noise is worse in the winter mornings or after the car has not moved for a few days and started with all the high Electrical loads switched on then it could well be the Alternator Bearings.

If your Suspension Ball Joints and Rubber Bushes are ok and your car still has the original Shock Absorbers then changing these should solve  your rough Suspension problems. After about 5 or 6 years, changing them usually makes a car feel almost like it did when it was new. 

Ive had the same issue just recently. the noise drove me absolutely crazy , it was going in for a cambelt and water pump replacement at the garage and i asked them to put a new drive belt on with it as theyd have to take it off anyway and it was in poor condition , cracking and fraying at the side , i thought this would resolve the issue but it hasnt its less frequent now and a lot quieter than before which leads to me one of the pulleys may be slightly throwing the belt out of alignment due to a bad bearing every now and then , i just dont know which one to replace and i dont really want to throw anymore money at the car because its 16 year old and not worth a whole lot. anyone had this issue before and got it fixed?