Recently spent $575.00 to have the alternator replaced on my 06 F-150 5.4 with 167,000 miles as it was whining. New alterntor was installed at my local garage, Truck was fine for about 2 weeks and now the loud whining noise is back. Anyone else had this problem. I'm thinking it might be the belt or a pully besring.

 

remove belt, start engine. If whine gone, then you know it is due to belt or an accessory. Turn off engine. Spin items by hand nd see if you hear or feel culprit. If not, put belt back on, strt engine, and try to locate by sound. Use stethoscope or similar device.

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Before I bought a stethoscope I used a metal rod. Just put one end in ear and other touching near each belt driven unit. But be VERY careful doing this.

 

How do you keep the metal rod in your ear ? lol

 

Brad nails.

 

Wow, that price seems exorbitant. I bought an alternator from big box store AZ, costs several hundred dollars and it whistled and took it back. I ended up buying alternator on eBay, new, for like $60 on closeout and you can buy same alternator for about $100 now. I actually bought another one as a back up that I keep on shelf in garage since I have more than one truck that uses that same alternator, saves time and money, not at the mercy of local parts stores and their high prices.
Takes about 15-20 minutes to swap from start to finish. Alternator runs great, no issues.

With that mileage, not a bad idea to change out pulleys, RockAuto has them for cheap, I paid $18.52 for two idler pulleys delivered SKPSK89006Smooth; local parts store wants $27.00-$34.00 a piece. Parts were exact match, same size, dimensions and good to go. I added a few drops of lube on bearings on new ones, don't know if it helps but it made me feel better!

 

LOL