Alternator fizzling ... not dead yet.

[philip]

Hi Al. A few days was the first time I noticed the alternator charge light coming ON at night.

> idle rpm and headlamps OFF: Alternator is fairly bright but goes out by 2000 rpm

> idle rpm and headlamps ON: Alternator is a little less bright and goes out by 1200 rpm

> high idle about 1200 rpm after starting engine and after glow plugs out: Battery VOM reads 12.6v and over about 2 minutes reaches 14.0v .

This alternator is the original part but for the brushes I replaced a couple of years ago. Considering that ... I don't mind replacing the whole assembly for a ready-to-go.

[philip]

wrote:
What's happening is that one or more diodes are failed/failing. The output is less. The VR boosts field voltage to try to compensate (increase the rotating magnetic field). The charge light is wired between the field and the battery and lights when there is a difference. In this case, the field voltage goes higher than battery voltage, light lights.

But either way, yes, you need to replace the alternator.

I stayed with NAPA ... at a NAPA store nearby. I bought the Premium alternator ($197) which added state tax ($18.oo) and core ($40) was $255. I'll have it in hand by 3:00 pm today (Monday). I'm not waiting around for the idiot light to stay ON.



Next day ... I returned the "core". $43.xx .

[philip]

Ah ... but there's more. This should have been a simple little job but it got "interesting."

The drive belt was snug. But when I removed the top alternator ear bolt, the whole alternator dropped down. Why? BOTH lower ear bolts were GONE. How about that!? Isn't that just special!

I should mention what a PAIN it was to get the alternator out ... thanks to the A/C. I did some trauma-yoga on this job. And the HARDENED hose on the vacuum pump to the engine block was NOT coming off the pump without breaking it. So... I separated the vac pump from the alternator.









Note this rear alternator housing ear bolt (there are two) is now 17mm head. This and the other was missing. Replaced with new bolts are 10x1.25mm and this time, 45mm long with shoulder not threaded.



** An important note: When I went to reinstall the vacuum pump, it froze up the alternator. I recall someone else here had this too. Knowing this possible in advance, the trick is to keep spinning the alternator rotor WHILE you're cinching down the vacuum pump. This plate has a round ridge facing the vacuum pump rotor which must face accordingly.



NAPA warranty and test. So keep secure this blue card and RECEIPT.






Oh... in case you want to have the right sized o-ring in advance (which I did not) ...

[philip]

Take a look at that ORIGINAL oil return hose from the vacuum pump. I left it this way because it was SO HARD and already leaking. It started to crack so ... I left it be until finding a replacement.

Yes ... it leaked even more after installing the new alternator.

And yes, I have found the OEM hose from local Nissan dealership. $34 and should be here within 7 days.