how would i no if my 5.0 needs a new alternator.. my friend and i have been working on my car for 10 hours straight.. changing parts and what not.. and it has a new battery in it.. but the battery isnt charging up or sumthin.. does that mean my alternator is shot.. sum1 please help!!!!

 

Advance Auto & AutoZone both test charging systems for free, just drive your car up there. Alternatively you could check your battery voltage with the car running... should be around 14 - 14.5 volts.

 

my battery is new.. i no that for a fact... the problem is.. it stays at around 8 volts or lower when the car is idle.. i dont think the alternator is working b/c it doesnt charge up the battery very good.. but im positive the battery is new

 

could also be a bad ground, could be bad connections on the battery, could be a fraided wire or the alt

 

well i just bought a new alternator... my friend and i tested the battery by putting jumper cables on 2 cars including the mustang.. and we established that the battery isnt the problem.. which is when we came up that the alternator was the problem... does that make sense?

 

It sounds like the voltage regulator or alternator. The voltage reg is mounted on the back of the alternator and it costs about $50. A rebuilt alternator will come with new regulator as well.

 

well im installing the new alternator today.. after it gets installed.. what should be different?? if the alternator was the problem.. does that mean my battery will charge and have more power?

 

You guessed it. It should run at about 14.5 volts all the time. The battery will only take a charge if the running voltage is higher than the battery voltage rating.

 

its at 12 voltz all the time.. i think thats normal too?