Driving home today in a blizzard (bonafide) and had something happen with the electrical on 06 expedition.

i had the blower fan on high, and the rear fan on medium, the headlights, foglights, flashers, and rear defrost on - just about the max load you can put on the vehicle.

everything was fine until i had to slow way down and the engine dropped down below 1000 rpm. if the engine dropped below that point, you could hear the blower fan slow down, and shortly thereafter the voltage gauge on the dash would start to drop as well.

that part isn't much out of the ordinary, but normally, the electrical would recover as the rpms increase just a bit. however, the voltage would not recover immediately as the rpms climbed.

at one point, the voltage had dropped after stopping to make a turn, and did not recover for a couple of minutes, and in that time the voltage gage was fluctuating on the low side of normal. then after a couple of minutes, the belt squealed, and the alternator came onboard, and the electrical recovered completely.

at the next turn, it would do the same thing. sometimes taking more than a minute for alternator to come back on board as the engine operated about 1500 rpm.

so i checked it out when i got home, and the alternator was covered in ice, and the entire engine compartment is covered in snow.

so my question is ... is the alternator failing? or is it just a case the worst case scenario that caused the alternator to not work right and the belt to slip at the same time?

it has never acted up before, but i've only had it a month or so.

the only other time ive ever had anything like this happen was busting through a snow drift in my explorer. that time the alternator quit working for a few minutes and came back onboard several minutes later down the road. so i know snow can do funny things.

any thoughts?

 

Sure, if the belt was slipping that's exactly what would happen. I would check the battery out too. An AC charge overnight wouldn't hurt anything.

 

thanks for helping!

forgot to state that the battery is brand new.

thinking more and more that it was just belt slip. a new belt is on my to do list, but was hoping to wait for warmer weather because it needs at least one new idler (can hear the bearings in the idler rattling).

i also noticed my hand was very black fom just touching the rib side of the belt.

our weather has just been crazy cold and snowy this year so i havent been able to work on it since i bought it.

do you think the ice in the outside of the alt. had anything to do with it? maybe drowning it out?

 

Prob had a LOT to do with a direct short!!!!

 

due to the ice?

very possible. not sure why it would be fine until the RPMs dropped to idle, though. then recover with a squeal after a minute or so. very bizarre.

it was fine today on the way to work and home.
i got a new belt for it, figured with 106k on the clock, it is probably due regardless.

worst case scenario, i suppose, is a new alternator is in order.

 

Belt slip seems likely . I would replace the belt and go from there .

 

I have the same thing happen sometimes when I plow snow on the state road. I normally don't, and am probably breaking some law, but there was a couple of times no one could get out, so I decided to make a couple of passes during a very bad snow storm. I normally don't plow very fast when doing my driveway and the parking lot I do, but plowing the road I got up to about 25-30mph, and after I went a little ways my belts started squealing also. I opened the hood and it was all icy and wet under the hood, plowing the snow stirred up a "snow storm" in front of the truck and it got all up in the engine.

I believe that's what happened to you, the belt got wet and icy and could not grip the alternator pulley.