I've got an issue that started a few days after I got my truck home. First time it acted up was when I had the socket for a fender light out while running to the Ford dealer. Figured it was from having it out. Went out shortly after I put it back in (When I turned onto the road). Figured that was the cause of the battery light. It wasn't. Came on a few days later right after I told my Dad I HAD a problem but it didn't seem like anything. Started the truck, light came on. Hit the skinny pedal (1,400 RPM at most, motor was warm) light flicked and went off. Truck sat 5 days at ~40*. Today go out started right up, no battery light. Drive ~10 miles. Turned off, run in a store maybe 5 minutes. Start it, battery light comes on. Again, rev to 1,200 (again, warm), light flickers twice, goes off. Go to parts store, maybe 10 mins. (regretting not just getting the repair book they had) Start truck, battery light comes on. Won't go off this time. Pull out on a little side street, little aggressive (2k shift) let off, light flickers but stays on. I think the light went off as I pulled onto the street. Drive a few mins. Go into Wegmans for a sub. Come out, start it, light is on again (no surprise at this point) Take the long way back to the house ~3 miles. Running @40-45 with 3 red lights, OD off @2200 RPM. (Been thinking it's the alternator at this point, seeing if the higher RPM helps) Get home light still on. Turn it off, eat. 30 mins later I leave for work, which is ~2 miles away. Light still on. Getting a little worried about it. Look down sitting at the light to turn into the parking lot at work, light is off. Come out 4 hours later ~40* out, starts up, no battery light.
Truck has ~97k on what I assume to be the original alternator. Batteries look new (750 CCA Motorcraft). The battery connections are tight, but a little corroded, but I can see metal all around. No engine light. No difference in starting. Haven't had the battery light come on with the motor cold yet, only warm. Belt has some play in it, I can push it in maybe 1/4-3/8" or so, with 1 finger. (truck OFF) I had my Mom run to the parts store (Pep Boys) and wanted her to just get me one, but they said there was a 90% chance it was the belt tensioner. (For the record a new "Ford" alt is $200, rebuilt is $169 from them) They said to watch the belt with the truck running and see if it has any "flop" to check if the belt is tight enough. Didn't end up getting one...
Tomorrow I have to drive ~100 miles. I have roadside assistance, but really hoping I don't have to use it. Is there any warning sign before it uses the rest of the battery power? (Volt gauge on the dash?)
Any ideas of what it could be? In the Morning I will try to clean the battery posts. Any special way to pull the cables off? (never done it with 2 batteries, I assume pull both negative wires first?) I may tighten the belt too, depending on if I think it's loose. Is it possible to test the alternator without taking it off and going to the parts store? (No volt meter
Parts stores are closed tomorrow, I work Friday and Saturday. Friday if we still have one where I work I'm buying a volt meter)
On a side note, I'm pretty sure they overfilled the oil.
Not by much. Getting oil this week, and it's already made almost 700 miles as it.