I have a remanufactured motorcraft alternator in my 99 ford f150 v6. the alternator has only 20000 miles on it in 3 years. about 2 weeks ago it starting making what i can best describe as a whirling noise and it definitely sounds like its coming from the alternator and is a bearing going bad. noise gets louder with higher rpm's and is constant each and every time I drive the truck. i bought a reman carquest alternator and that seemed to only make it louder. i then bought a new carquest alternator which didn't fix the noise. (both from advanced auto). then i replaced the tensioner pulley assembly and then the lower idler pulley. neither fixed it. finally i bought a new duralast battery from autozone and that didnt work either. battery tested normal above 12 amps even though its 6 years old now. all other pulleys are quiet and have been replaced within the last few years. the belt is 2 years old and looks good. what is the problem? belt alignment? its seems fine. the truck has 120k
What makes this problem better or worse?
nothing
How long has your 1999 Ford F-150 had this problem?
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Hello, noises are hard to determine here in this forum, and it sounds like you've looked at multiple areas. Tensioner and idler pulleys can be at fault, but every other pulley can be as well, from power steering pump to air conditioning compressor. The components themselves may be a failure, not just the pulley. Hands on testing is needed. When you remove the belt and run the engine -- does the noise stop? If so, then you definitely have a concern with one or more pulley's or belt driven components.
