Squeal/Sqeak/belt slipping sound

[jakex181]

Ive noticed when accelerating ill get a strange sound much like a belt slipping for a second at around 2k revs, i originally thought it was the belt slipping but today i planted my foot in 6th gear and the sound was still made even with the engine not revving lots which leads me to believe its not the belt slipping? am i right in thinking this? Does anyone know what it could be?

[PhilNUK]

Could it be the alternator pulley? I had a sound like that on my mk4.. The pulley eventually snapped completely and the whole car shut down. I might be wrong! I don't remember it being specific to the revs. Was more a constant squeal noise

[doylebros]

As above says - this is worth a read:-

http://www.mk5golfgti.co.uk/forum/index.php/topic,73597.0.html

[jakex181]

Its not constant, it only happens if i when i accelerate at full throttle, even in a high gear if i push the accelarator to the floor it will still make the noise

[jakex181]

Not a very good video and hard to hear but i think it sounds similar to this and happens aswell when i accelerate.

Underneath the guy says it was a leak in the EVAP system, is this something i can check?

[jakex181]

Any one have any ideas, still doing it :/

[Scottymon]

Have you checked your alternator pulley bud?  It will make a noise under different loads.

Disconnect the battery, remove the engine cover, move the charcoal canister to one side, grab an open ended spanner and pull the tensioner towards the front of the car and place an Allen key through the hole to lock it out. 

Remove the belt and check for wear.  Place a long thin screwdriver into the alternator to stop the blades turning and turn the pulley backwards and forwards, it should lock on way and freewheel the other, if it locks both ways or free wheels both ways then you'll need to replace it, they are about thirty quid and the belt a tenner.

Also, a good idea to spin the idler wheel on the tensioner to see if that is squeaking too, should be silent.

If not those it could be the K03 chirping, some do some dont, most audible when a CAI is fitted.