2005 Dodge Caravan, when starts up, weird noise from either the belt or the alternator? After a few minutes sounds normal. Does when idling when first started, and even a little while while driving. Can't take it in anywhere to get diagnosed as will stop that noise and sound normal after a few moments before I get to a garage. I already tried taking it there, and they told me I have to bring it back when it is actually doing it. Seems if I start the van once during the day, it won't do it again if I start it later that day. Will do it again the next day or maybe 2 days later. Used to do it when real cold in the winter, under 20 degrees, and then stopped when the weather started warming up. Just started again a week ago, even though it's been generally in the 80's. Link to Youtube video I made on it below, a few seconds before I got the hood open, and a few seconds after, and then the sound changed to the usual engine noise for my van. Any help appreciated for maybe what to tell the garage when I take it there. I know maybe just a loose tensioner or pulley, but then wouldn't it do it all the time? Also I have one of those gadgets that puts mp3's on your FM radio which plugs into the cig. lighter socket, and when it goes on, will give you the car's voltage, and always around 11.8 or so when first started, and up to 13 something after a minute. Is that normal starting voltage or have something to do with the noise problem? Could there be a bad fan? Again, once it kicks in to sounding normal, will stay normal for the day. Thanks!

https://www.youtube.com/watch?v=v7nh...ature=youtu.be

 

1) When the engine is cold enough for the noise to be present, Make sure the AC is OFF when you start the engine. If the noise is there, turn the AC on to see if it goes away. If it’s not there, turn the engine off and set the AC to on, then try starting it again. If the noise is there, turn the AC off. You’re testing whether or not the compressor clutch is slipping and what condition causes it.

2) Remove the belt and inspect it for cracks, worn grooves, and chunks that have been torn off. Replace if needed.

3) While the belt is off, spin each pulley by hand. Listen for noise, feel for roughness and rock each one back and forth to check for play in the bearings. All pulleys should spin freely and have no side to side or top to bottom play.

4) Start the engine with the belt off for a moment. If the noise is there without the belt, either the crank pulley is rubbing on something, it’s internal to the engine or it’s coming from the transmission.

 

The voltage sounds low. Then again, you're not using the actual volt meter. Get a digital volt/ohm meter. Set it to 20 volts and start the vehicle. It should jump to 13.5 volts or higher as soon as the engine is running. Between a sound that goes away when warm and low voltage, I'd say you have a bearing trying to pack it in on the alternator. Now, you CAN buy the bearings and put them in. It will cost almost as much as a rebuilt and you'll still have old brushes. Myself, I'd pull the alternator and have it bench tested.To track it down a bit more, especially if it's making the noise, get a wooden dowel rod about 2 feet long. Put your knuckle on the end and use that knuckle to press the flap of cartilage at your ear shut. Now put the other end on the alternator and you can hear any noise the bearings are making. Your knuckle amplifies the sound as well as keep the rod from ramming into your ear if you hit something moving.

 

Thanks GumbyRT. I always shut everything off when I shut off the van including the A/C, so when I start it, nothing was left on. I can't have the A/C ready to turn on when I start it, only the fan. The A/C buttons are off till I press them. Made no difference when I pressed them on last time I started the vehicle, with the noise, and I pressed the A/C buttons on, I think one is A/C and the other is recirc. All the rest, I'll have to visit a mechanic for, but I can print this out when I take it in, especially as it probably won't be making the noise once warmed and at the mechanic's, unless i leave it there overnight.

 

Thanks ol' grouch. I may have mis-guessed what the device I have said about voltage, it's not a voltmeter, but does jump to 13.5 or so within a couple of seconds, whether that noise is present or not. I would have to take it to a mechanic, maybe leave overnight, to see if it will make the noise for them, and print this out in case they need something to go on. But I'll try the dowel thing, thanks. Hope it works better than using a hose, which is tough.

 

Does the noise change at all when you turn the steering wheel? I've heard of worn power steering pump shaft seals allow air to pass into the suction side, cause cavitation/noise, but stop after the seal heats, expands. Just a guess...