Alternator help
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Tuned
Joined: Jun 2008
Posts: 266
Likes: 7
Alternator help
Been driving all week long, watched my operating voltage drop until it hung out below 12 volts and the battery light was on. Was in a remote area and finally came to a napa, where I got a rebuilt alternator. Was fine for several hundred miles yesterday, then it too started acting different. All day today it would vary between around 12.2v with the battery light on and about 13.6v. It stays on one of those two for like 5-10 minutes at a time then switches.
Where do I go from here? I don't see anything wrong with wiring, and turning stuff on or off doesn't seem to make much difference at all.
I'm staying in a town with several parts stores tonight, but heading out remote area tomorrow, do I need to grab a different alternator before I leave?
Where do I go from here? I don't see anything wrong with wiring, and turning stuff on or off doesn't seem to make much difference at all.
I'm staying in a town with several parts stores tonight, but heading out remote area tomorrow, do I need to grab a different alternator before I leave?
Senior User
Joined: Nov 2015
Posts: 300
Likes: 6
From: Tampa
I read too many of these threads when mine was going bad so I went with the 185 from Ficm repair. It amazed me with the number of members on here that switched out there alternators 2,3, or 4 times after getting bad ones from Napa, oreillys, etc. Good luck with the fix.
Lead Driver
Joined: Apr 2016
Posts: 7,170
Likes: 1,331
From: Bahstun
12.2 is a bit low.
Turn on ignition for one minute to let GPs drain batteries a lil and turn off.
pull ground one battery and measure Volts on both batteries, if one is lower then they are fighting and causing alt to over work.
Turn on ignition for one minute to let GPs drain batteries a lil and turn off.
pull ground one battery and measure Volts on both batteries, if one is lower then they are fighting and causing alt to over work.
Former Vendor
Joined: Mar 2016
Posts: 125
Likes: 0
I have personally seen many people buy (and then warranty many times) aftermarket alternators on these trucks. I do not know what it is but the aftermarket alternators do not work as well on these trucks. I would suggest getting a Ford/Motorcraft alternator for your truck. As long as you have the single alternator set up you probably need Ford part number F81Z10V346EBRM (Motorcraft number GLV8666RM).
Post Fiend
Joined: Mar 2007
Posts: 26,966
Likes: 50
From: Texas
Check your wiring and grounds to make sure that's not the source of the electrical issues. I've had a "lifetime" alternator from Autozoo stop working properly before I could get out of my driveway. Ended up killing the batteries.
I got tired of the game about 4 years ago and did this. https://www.ford-trucks.com/forums/1...lternator.html
Still running that same alternator today. Currently have over 550k on the motor so it's not like it doesn't get it's exercise.
I got tired of the game about 4 years ago and did this. https://www.ford-trucks.com/forums/1...lternator.html
Still running that same alternator today. Currently have over 550k on the motor so it's not like it doesn't get it's exercise.
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Tuned
Joined: Jun 2008
Posts: 266
Likes: 7
I took the truck down to napa where they tested it both in and out of the truck and it failed both times. I paid an extra $30 to get a brand new alternator while I was there, he even tested it for me and it passed, and has worked properly all day long!
I have not turned in the original oem for the $90 core charge yet in case I decide to have it rebuilt. I've got an extra alternator back home from a v10 so I'll probably just turn that one in.
Thanks for the help!
I have not turned in the original oem for the $90 core charge yet in case I decide to have it rebuilt. I've got an extra alternator back home from a v10 so I'll probably just turn that one in.
Thanks for the help!
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Elder User
Joined: Sep 2011
Posts: 979
Likes: 4
From: Vancouver
we are seeing the result of commonly used parts for rebuilding and building new alternators being sourced from a certain Asian country where price instead of quality is important. The bearings and electronic components of the alternator are what usually fail. The auto manufacturers are more diligent about writing contracts for new parts and confirming that they meet oem specs. The manufacturers that are selling to the replacement market and the repair market are cutting expenses to meet those price points.
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