2006 Dodge Durango whistling noise

14PROTOMAN

MEMBER
2006 DODGE DURANGO
5.7L
V8
AWD
AUTOMATIC
105,000 MILES

When my truck idles there is a whistling noise and as you accelerate the whistling kinda goes away and when you're driving down the road the battery light will come on but nothing dies out. Everything continues to run normal. If the alternator was bad I would no power at all and everything would die. Also you can hear it insode the vehicle as well. I think it might be a pully going bad. Anyone have ideas.

1 Reply

CARADIODOC

MECHANIC
33,916 POSTS

You're misinformed about losing electrical power. Everything on the vehicle is powered by the battery. The alternator keeps the battery charged, and when it fails, the battery will continue to run the electrical system for as much as an hour, depending on how many things you have turned on. With a charging system failure, you'll see the voltmeter on the dash drop from around 14 volts to around 12 volts, the head lights will dim, and the heater fan will slow down.

The most common cause of an intermittently-dead charging system is worn brushes inside the alternator. The assembly costs around $15.00, but most people just replace the entire alternator after diagnosis proves it's not working.

Given the low miles and the noise, check the idler pulleys for the serpentine belt first, and check if that belt is tight. A loose belt will allow the alternator pulley to slip and the alternator will stop charging. That will be worse if it's raining.