Dead alternator?
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Fleet Mechanic
Joined: Aug 2000
Posts: 1,504
Likes: 1
From: Texas
Dead alternator?
Last night on my way home I lost overdrive on my truck (05 F250 5.4). Shut the truck off thinking it was a momentary glitch (have had a couple of those in the last three years) and when I hit the key to start it back up, I got nothing. Coasted it to a stop, and let it sit for 5-7 minutes, tried again and it have me the battery click of death. Waited a few more minutes and it finally started up, drive it two blocks to the house and let it sit.
Here's what I've got, optima yellow top (3-4 years old) truck has the original alternator.
I'm not used to having everything be electronic in my truck since I just bought this one 3 years ago after having my 92 for so long. Anybody have any ideas?
Here's what I've got, optima yellow top (3-4 years old) truck has the original alternator.
I'm not used to having everything be electronic in my truck since I just bought this one 3 years ago after having my 92 for so long. Anybody have any ideas?
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,678
From: Stephensville WI
It could be the battery or it could be the alternator, or it could be that dreaded "something else". Do not replace any parts without first getting them tested. Replacing good parts is a great way to waste money.
First, charge the battery.
Now, get a volt meter. Take a reading from the battery. Now start the truck. Take a reading while the engine is running.
Does the voltage go up when the engine is running?
YES: you probably need a new battery. Get it tested.
NO: You probably need a new alternator. Get it tested.
First, charge the battery.
Now, get a volt meter. Take a reading from the battery. Now start the truck. Take a reading while the engine is running.
Does the voltage go up when the engine is running?
YES: you probably need a new battery. Get it tested.
NO: You probably need a new alternator. Get it tested.
Thread Starter
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Fleet Mechanic
Joined: Aug 2000
Posts: 1,504
Likes: 1
From: Texas
Ok, checked the battery before starting and after.
Before 9.5 volts
After 12.5 and never went any higher
Now after starting the truck I heard what sounds like bearing noise coming from the alternator. I just changed the belt a few months back so that's definitely not it.
Already have a line on a new 130 amp alternator, and the battery is on the charger as we speak.
Before 9.5 volts
After 12.5 and never went any higher
Now after starting the truck I heard what sounds like bearing noise coming from the alternator. I just changed the belt a few months back so that's definitely not it.
Already have a line on a new 130 amp alternator, and the battery is on the charger as we speak.
Thread Starter
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Fleet Mechanic
Joined: Aug 2000
Posts: 1,504
Likes: 1
From: Texas
My brother in law and I have had nothing but good luck out of Optima's. He was running a massive system off of two yellow tops and getting some really heavy results!
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,678
From: Stephensville WI
Ok, checked the battery before starting and after.
Before 9.5 volts
After 12.5 and never went any higher
Now after starting the truck I heard what sounds like bearing noise coming from the alternator. I just changed the belt a few months back so that's definitely not it.
Already have a line on a new 130 amp alternator, and the battery is on the charger as we speak.
Before 9.5 volts
After 12.5 and never went any higher
Now after starting the truck I heard what sounds like bearing noise coming from the alternator. I just changed the belt a few months back so that's definitely not it.
Already have a line on a new 130 amp alternator, and the battery is on the charger as we speak.
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Senior User
Joined: May 2012
Posts: 192
Likes: 0
From: Derby, ks
Spray some wd40 on the idler pulley, tensioner pulley, and alternator pulley.. Do one at a time and see when the squeak goes away.. Then you know what's mashing that .. More that you have checked the battery and alt with a volt meter doesn't always mean it's still good.. It can have a dead cell and give the appearance it's good.. Once it's fully charged..take it to your local auto parts store and have then do a load test on it.. Then you will know if it is truly good oror not..
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FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,678
From: Stephensville WI
Basically, the rise in voltage means the alternator is putting out something. The battery doesn't seem to be retaining it. 9.5V with ignition off tells me you probably have at least one dead cell in the battery.
Elder User
Joined: Jun 2013
Posts: 712
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From: Booneville, Missouri
Electrical Problem
Ok, checked the battery before starting and after.
Before 9.5 volts
After 12.5 and never went any higher
Now after starting the truck I heard what sounds like bearing noise coming from the alternator. I just changed the belt a few months back so that's definitely not it.
Already have a line on a new 130 amp alternator, and the battery is on the charger as we speak.
Before 9.5 volts
After 12.5 and never went any higher
Now after starting the truck I heard what sounds like bearing noise coming from the alternator. I just changed the belt a few months back so that's definitely not it.
Already have a line on a new 130 amp alternator, and the battery is on the charger as we speak.
A good battery should read 12 Volts with the engine OFF.
It should also read at least 14.1 when running.
I have an Interstate battery with 850 Cold Cranking Amps and have not had any problems.
Take care
Boon
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Fleet Mechanic
Joined: Aug 2000
Posts: 1,504
Likes: 1
From: Texas
Took the battery off charge last night and had a 12.95 volt reading with 1.5 amps left on the charger after charging for 6 hours.
Will get it tested but with the truck running off of battery only it would have drawn the battery down that far from almost an hour trip home.
Will get it tested but with the truck running off of battery only it would have drawn the battery down that far from almost an hour trip home.
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,678
From: Stephensville WI
OK, this is why in my instructions said to charge the battery first.
Was the 9.5 volts before or after the battery was charged? It makes a huge difference in troubleshooting your issue.
Was the 9.5 volts before or after the battery was charged? It makes a huge difference in troubleshooting your issue.