Alternator Problem?

Last weekend my engine started to whine loudly. Noticed today that it was a bit slow to start, and after a bit of checking the truck seems to be running about 9.8v instead of the normal 13.4v. Doing some research, seems be various possibilities for the whine including alternator. Should I just have the alternator replaced or is there anything else I should consider?

TIA,
Richard

 

If it’s the alternator that is making the noise, replace it.
If it is not the alternator making the noise, I’d get it checked (auto parts stores can typically do this)
If you do replace the alternator, I would avoid anything other than an OEM or Quality OEM Reman.
Stay far away from the “parts store” alternators. If you absolutely have to go aftermarket, NAPA is the best place. But try to go OEM.

 

What do you mean "the truck seems to be running at 9.8 volts"? How/where are you measuring that?

Agree that the alternator is a likely culprit. Get a piece of hose long enough so that you can put one end on the alternator and the other to your ear. Start the truck and use the hose like a stethoscope (assuming you don't have a mechanic's stethoscope). If the bearings are going, it will be VERY apparent, and then yes, replace or rebuild your alternator.

 

I have a ham radio wired to the battery that does a voltage check when I power it up. That normally reads 13+v, was reading 9.8 today. Also, when starting it up today it felt like the battery was weak. Battery is one year old.

 

You are in an area big enough there should be some good electrical shops around. Find one and let them test the system and repair as needed.

I don't know if your CB is measuring start voltage or run voltage. It's not impossible for a new-ish battery to fail, but they are more apt to just do nothing. So the alternator output definately needs checking.

 

If your battery is currently at 9.8 volt, I wouldn’t drive it any more. You likely won’t make it far.
You’re on borrowed time the way it sits. Charge the battery and have it tested.
I betting it’s the alternator, but you need to have the battery charged and checked any how.

 

I assume you are saying your alternator is putting out 9.8V. If your battery was measuring 9.8V it’s basically dead and wouldn’t start your car. Measure your battery voltage with the engine off. You should get 12.42 or higher (12.42 is about 80% charged)To measure alternator V, with your car running measure voltage across your battery again. You should get about 13.8 or a little higher. If the battery is low and alternator output is low you probably need a new alternator.

 

Check your battery connections, cable condition(no corrosion), and alternator connection. Remove serpentine belt and check alternator for smooth rotation, if notchy or sloppy, replace(draw a diagram before removing). Check the operation of other pulleys while you're in there. A bad idler(or other accessory) can cause the serpentine belt to slip and not spin the alternator.

Don't continue to drive it. If you're alternator isn't working you'll be running solely on the battery, or a poorly charging battery. You'll be deeply discharging your battery, which will kill it too.

 

Gen 2 the Dealer does not sell new OEM alternators only Denso rebuilt as OEM (notice the part # has a rebuilt code vs new code).
Dealer says they replace all components at about $400 but the Denso rebuilts you get from Rockauto or Carid at about $125 do all the bearings and other components that don't test out. Believe what you may. Many posts on alternators.