2005 Civic Alternator problem (low voltage when loaded)

[thekaranimal]

Hey All,

I'm in the process of purchasing a 2005 Civic SI-G, and while the car in general is great, there have been some issues. The biggest has been a faulty alternator. I took the car to a Honda dealer for a comprehensive car inspection and they told me that the alternator had to be replaced as:
Alternator output @ no load = 14.37V (good)
Alternator output @ load (lights, AC, defroster on) = 12.54V (bad)

I took the car back to the used car dealer to get the alternator replaced, and they claimed to had replaced it. I then took it back to the same Honda dealer to get re-inspected, and they reported:
Alternator output @ no load = 14.34V (good)
Alternator output @ load (lights, AC, defroster on) = 12.50V (bad)

Just to be on the safe side, I took it also to a Honda performance shop, and they confirmed the low output... they mentioned that the alternator should produce an output of 13.0-13.2V, when under load. As a side note, all other electrical checks (battery, crank test, diode ripple) were normal.

What should the alternator voltage output be with and without load? Is this alternator bad? Should I hold off on the purchase until an alternator that produces an output of >13.2V be put in, or is that unrealistic?

Thanks!

 

[RonJ]

I think the alternator is bad and should not drop very much below 14V even under high load. Does the dash charge/battery light remain on while driving with the lights on?

 

[thekaranimal]

The battery light on the dash doesnt come on, and the car starts fine, but I found out from Honda that at the battery light will start to flicker at a voltage output of < 12.4V.

I also dug around and found a 7th gen Honda civic service manual, which contained an alternator test. The simple test procedure explains that the output of the alternator should be 13.9V and 15.1V when under load (radiator fan on, headlights with high beams on). Further, the alternator needs to produce an output of at least 60A @ 13.5V when under load (rad fan on, headlights with high beams on, blower motor, rear window defogger, brake lights, etc.).

The original and replacement alternator were both bad parts.. I hope the guy finally realizes and puts in a good part.. and I can finally get my Civic!!

Thanks