2004 GMC Sierra 1500 Q&A

2004 GMC Sierra 1500 Question: engine makes squeaking nosie under the hood. its a 4.3 ltr

have replace the following parts already, serp-belt, belt tensioner assy, idler pully, and alternator and it still makes alot of squeaking noise when on higher rpm, more so when the AC is on. what could be a possible problem? -
Answer 1
Take the belt back off and see if the noise is still there when start the engine. I found a pesky water pump front bearing noise when I did this on a vehicle. You can turn the individual components by hand and see what you feel or hear. -