2004 Ford Focus SE 2.3L 241K miles started hearing a whining noise and burning plastic smell around the area behind the coolant tank. Only things in that area are the alternator, accessory idler pulley, and the belt tensioner all of them seem to be turning and the belt seems fine and undamaged. While idling the battery icon briefly lit up and the car stalled shortly after. I was sure it was the alternator but when I hooked up at multimeter on the battery it showed it was still charging the battery at 13.6v. Suggestions welcome.
whining noise ... battery icon briefly lit up and the car stalled shortly after.
If the battery warning came up, then voltage dropped low. So try to recreate those conditions and measure again. Get an electrical test done like Scotty says (its free at the parts store). It could also be a failed battery, which is why you always test them together.
As for the whine, remove your accessory belt and turn the alt pulley by hand to see how it feels. But it might have just been straining to charge the battery.
Go over all your electrical connections too. Battery terminals, alt connections, grounds, etc. Make sure they're clean an tight. Check the fusible link (easiest way is probably to measure resistance across the alt positive cable)
seem to be turning and the belt seems fine
A worn belt is hard to see with the naked eye. The grooves need a minimum depth or it starts slipping. There are checker tools for this, but if it hasn't been changed in a while then just do it. They're not expensive.
smoke ... burning plastic smell
Make sure you don't have a oil (from a valve cover, main seal, etc.) seeping down onto hot exhaust.
Alternators need more than just voltage check to see if they're working correctly. You have to check the diodes you have to check the amperage and of course if the bearings are starting to go out it'll whine and smoke cuz it's dragging too much. I would take the belt off and try to turn things and if you find turning the alternator is really hard then that's it for sure
A bad or weak battery can create seemingly inexplicable symptoms. Checking the condition of your battery and alternator are typical first steps when troubleshooting anything electrical on a car. Thank you for the update.That doesn't really explain any of it as far as I'm concerned but he's the expert and it's been running fine for the past few days
The belt was changed a couple of years ago as was the valve cover gasket. Basically, after attempting to get to the alternator and not even being able to find the belt removal tool, I decided the job was beyond my shade tree experience and since it was cold I just didn't want to bother. I threw in the towel and took it to my local mechanic he tested the charging system and said it was fine. The problem was the battery had a bad cell seems odd since that battery wasn't that old. As for the burning smell he said probably just some oil got on it. That doesn't really explain any of it as far as I'm concerned but he's the expert and it's been running fine for the past few days. Thanks for the help.