1993 Legacy Charging System / Alternator

[union76]

Can anyone recommend a place where I can buy a reman'd Subaru alternator? Autozone quotes $120, but I've heard unreliable stories...

 

Cold voltage across battery: 12.8v DC (battery is only a few weeks old)

Initial idle voltage across battery: 14.1 v DC

Loaded voltage across battery @ 1800RPMs, running fan and lights: 13.6 v DC

Drain test: 4.5 amps. Does this mean bad alternator for sure? Or could it be connections/wires?

 

Although the voltage starts out at 14.1v, the voltage becomes irregular even after taking off the load, bouncing +/- 0.1 around 13.5v.

 

I have started hearing a slight whining sound at idle, which I recall was associated with the demise of the previous failed alternator (an alternator shop diagnosed it as a bad voltage regulator). The current alternator has been in service for two years (20k miles), after I pulled from a wrecked 1992 legacy.

 

Thanks.

[john in KY]

If you are sure the whine is from the alternator, then it is on the way out. Another "test" is to feel the alternator after the engine has been running for a few minutes. Too hot to touch means it is dying also. Those voltage amounts don't sound all that bad to me. You can use a much newer Subaru alternator if you want. Only difference will be the alternator plug. Lot easier to find a 95 and newer alternator than that old one. Just take the plug.

[porcupine73]

Make sure you check the Subaru dealer sites such as subarupartsforyou. Sometimes the genuine Subaru reman'd is less than the parts store junk alts.

 

Those voltages you listed sound just fine to me. I woudn't say it moving +/- .1V is unstable at all. It might just be your meter doing that.

 

What do you mean the drain test was 4.5A? (Can you say how you measured that).

 

Let's see looking at it, if it's just the plug that's different, using the '95-99 Legacy alt might be a way to go, those look to be about $125 for genuine Subaru reman'd. The 94 and earlier are twice that much.

Edited July 30, 2010 by porcupine73

[Fairtax4me]

Whining at idle could be any bearing on the engine. Take the belts off and spin all of the pulleys by hand and listen/feel for roughness. You can even start the engine without the accessory belts on to help determine if the noise is coming from one of the accessories or from elsewhere (such as a timing belt idler).

 

 

What do you mean the drain test was 4.5A? (Can you say how you measured that).

Yes, a more detailed explanation would help.

If you determine that it is in fact the alternator (which I don't see any other reason for thinking that besides something is "whining")

1stsubaruparts.com has the 95-99 alternator PN 23700AA34ARA listed for $67. Might be worth a swap at that price?

OR, you can try to find a rebuilder in your area.

[porcupine73]

Ah yes $67, I was trying to think of the place that had it at that price. I think that particular one is less expensive because there was a recall on those alts around '96, something about the brushes and losing power. So Subaru probably needed a boat load of those alts for that campaign.

[union76]

Thanks for the advice.

 

I found a local alternator rebuilder. It will be about $80 to rebuild my old alternator (new voltage regulator and diodes).

Out of curiosity, if I get a reman'd 1995-1999 Legacy alternator from 1stsubaruparts, how difficult is it to splice on a new 2-plug (vs the old 3-plug)?

 

I am almost certain the alternator is going bad.

- The initial idle voltage is 14.1VDC across battery, but it starts to drop without adding any additional load to about 13.2, and fluctuates. The amps also drain, perhaps from a faulty diode in alternator. The battery is only barely charging.

- Alternator gets very hot to touch.

- Occasionally, I hear a click sounding from the dash, presumably a fuse. (same sound as CEL light coming, or engaging the defrost or cruise control). But there are no CEL codes stored in memory. ECU must not like low voltage.

 

For future reference,

the part number for 1990-1994 Legacy NA is 23700AA090 (3 plug). Subaru reman'd units are going for $210+. Diagrams and specs are available in section 6 of the FSM (http://www.main.experiencetherave.com/subaru_manual_scans/1992_FSM_Eng_and_Elect/).

 

the part number for 1995-1999 Legacy NA is 23700AA34ARA (2 plug). Reman'd unts are going for $67.

[union76]

With some kind and knowledgeable help from the boards, replaced the 1993 alternator with a reman'd standard 3-prong 70 amp unit for $80.

 

Voltage across battery at start: 14.2 VDC

Voltage with lights and fans on: 13.8 VDC

The high-pitched whine has gone away. The power windows operate noticeable faster.

 

I suspect the voltage regulator was going bad on the old unit.

 

A new OEM 3-prong unit for the 1990-1994 Legacy is around $300. The 2-prong 1995-1999 units are $125 (you'd need to splice the plug).

If you can find a reliable alternator shop that you trust, use them, or as other people have suggested, http://www.maniacelectricmotors.com/13275.html has reman'd units for $79 with prepaid return of the core.

[Manarius]

Hmmph, now only if SVX replacement alternators were only $67 ($197 + shipping from 1st Subaru Parts )

[union76]

Have you tried

http://www.maniacelectricmotors.com/39allal13.html

for your SVX?

[Olnick]

how difficult is it to splice on a new 2-plug (vs the old 3-plug)?

 

So how do you splice it? Is there a how-to-do-it writeup or schematics or pix anywhere?

[union76]

There is a (brief) discussion on one of the other boards, describing how each lead functions:

 

http://bbs.legacycentral.org/viewtopic.php?f=19&t=40943