Whining noise from engine.

2005 Toyota Tacoma. 2.7 Liter
Have a whining noise coming from engine . I think it is an idler pulley. My question is, how do I test to see if or what pulley is bad. what is entailed to change an idler pulley. Would like to save a few bucks and do this myself if I can. Any help would be appreciated.

 

You can remove your serpentine belt and start the truck to confirm. Changing idlers is easy once the belt is off, but they're not cheap for what they are. I found that the belt is easier to remove from the bottom, just be sure to make yourself a belt routing diagram, it's kinda funky. Being a 2005, you may be 100k or so. If so, replace them all and put on a Goodyear Gatorback belt if you plan to keep it and run it long. Also make sure that you're not weaping any antifreeze from the water pump bleed hole. I would pull the belt and then spin and wiggle each idler to test. An automotive stethoscope is also helpful before you pull it apart. They're pretty cheap at the chain auto stores.

I replaced my belt and tensioner at 125,000 on my 2006, I never changed the idlers. I had 175,000 when I traded it in. Alternators can whine too.