high pitch noise/whistle sound coming from i30

[handz1000]

are these huge issues with i30s i have been on the scout to buy a 2nd gen 96-99 i30 about 3 of them i have looked at have had this whistling noise/high pitched sound coming from them..some go away ,and some just start as soon as you turn the car on ..i was told it could be a vacum pump or some timing/belt issues..or even pully bearings

i still can not decipher the issuse as i am no mechanic.

is this something that would be huge to fix or is it a known problem ?

[loystock]

Most likely from Idler Pulley. You can verify using a Mechanic's Stethoscope ($6 from Harbor Freight) and poke it on NON-MOVING component of the pulleyy. The part is not expensive and is not difficult to replace. Check the AC compressor (clutch)if it is engaging normally when AC is ON. Make sure the CEL is working (must be ON with Ignition ON and goes OFF once car has been started.