[Scotty_B]

First, here's a link to a thread that helps describe my problem: Alternator Positive Lead Melting

I'm updating this with new pics, and I hope some of y'all can help me out with getting me back on the road. Please forgive me if I don't know the name of all the parts. Maybe some of you can help me with that, too.

I've got one of those OBDII dongles that interfaces with software on my cell phone, and it sometimes registers less than 12 volts coming into the dongle when the engine is off but the key is in the "on" position. And it registers about 13 volts when I am driving, according to the live data, which seems a little low to me. But when I measured the voltage from the battery with a multimeter at idle, it registers over 14 volts. All a little strange, to me.

When I examined the wiring, I noticed the red rubber boot over the alternator positive lead connection was hard, cracked and deteriorated, so I ordered a new one.

When I went to remove the old boot, the post broke off when I tried to loosen the 12mm nut that fastens the wire to the post. It snapped right off without a whole lot of force. Also, the two stranded wires that were crimped onto the connector are in bad shape. Black and burned. In fact, they broke free from the connector fairly easily.

The entire housing that bolts into the alternator looked pretty melted, too. I wanted to see if I could remove that housing, but I can't find a socket that fits it. It doesn't seem to be a hex bolt. It seems to be a round bolt with two flat sides, and there is little access to get something on it to loosen it.

I don't think the alternator is bad, but I can't find anyone who sells just that little housing around the post connection.

ALSO, when I removed the wiring harness from the alternator, I noticed that there were only two wires going into a 3-wire harness. Is there something wrong, here, too?

So my questions are:

Is there anyway to replace only the housing around the positive post on the alternator? I can't find a salvage yard within 20-30 miles that even has a Subaru.

If I need to replace the alternator, am I better off getting OEM used or a remanufactured or aftermarket one? However, even if I need to replace the entire alternator, my biggest concern is how to rewire the alternator, given the deterioration of the existing wire.

Can I remove some of the insulation to the point where the wire looks okay and splice something onto it so I can make a new, clean connection?

If I can do that, what would be the best way to make the splice and replace the insulation?

At 220K miles, I'd rather do the work myself instead of taking it somewhere and having a dealer or a service shop replace the entire wiring harness at major expense.

Can I do this, or am I SOL?

 

[2.5x_sleeper]

I'm going to say you'd be better off getting a replacement alternator. Consider it a good opportunity to upgrade to an 110A XT alternator, vs. the 90A alternator your '03 came with! :biggrin:

The plug is correct, your alternator is a 2 wire. I believe the earlier generation had 3 wire alternators.

As to the cables. Those are parallel cables going to the same place, so you can cut it back to where you can make a splice. I believe the factory used 2 small cables for flexibility? You can use one cable or 2 as the factory did, I'm good either way, as long as the single cable is equal to the 2 single cables. :wink:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]

 

[Scotty_B]

Thanks for the super fast reply! If you had to do that repair, what kind of replacement wire would you look for? Maybe something for battery cables you could find at an auto parts chain? Would that work? And how would you go about making that splice? I've got a little home electrical repair experience. So I have some understanding about making good connections.

And how would you insulate the wiring? I actually have several grades of electoral tape, including some self-fusing silicone tape that's supposed to be waterproof and good up to 500 degrees. Would that work? Or would some kind of sleeve work better?

 

[Scotty_B]

Bobby,

When I do searches for 110 amp alternator searches for a 2003 Subaru Forester (on eBay and Amazon), they all come up as incompatible. Is that because OEM spec is for 90 amps?

How do I make sure an alternator is compatible with my vehicle?

 

[2.5x_sleeper]

The '03 only came with a 90A alternator. the '03-'08 non-turbo came with the same 90A alternator, whereas the '04-'08 XT... turbo engine came with the higher output 110A alternator.

The fitment is the same, but if you search for '03 alternator, the XT... '04-'08 will show incompatible, as that's not what your '03 came with. :wink:

► Disclaimer - always verify any information you read on the internet, especially if you're going to spend money on parts! :icon_eek:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]

 

[2.5x_sleeper]

Thanks for the super fast reply! If you had to do that repair, what kind of replacement wire would you look for? Maybe something for battery cables you could find at an auto parts chain? Would that work? And how would you go about making that splice? I've got a little home electrical repair experience. So I have some understanding about making good connections.

And how would you insulate the wiring? I actually have several grades of electoral tape, including some self-fusing silicone tape that's supposed to be waterproof and good up to 500 degrees. Would that work? Or would some kind of sleeve work better?

The wire you use needs to be equal to what you replace. For use in the engine, it need to be fuel & oil resistant. Of course you want stranded wire with lots of strands, as you want flexibility.

As to the splice.
I would crimp & solder. Once crimped, soldered or both, to protect the splice, I'd coat the splice with dielectric grease, then slide shrink tubing over the splice. When the shrink tubing is heated, it will shrink & excess dielectric grease will be expelled. That assures no water can wick under the shrink insulation.

I'm not a fan of electrical tape, unless it's for temporary use. I prefer heat shrink tubing. For critical applications, I'll use 2 layers. :wink:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]

 

[Scotty_B]

Bobby,

This doesn't list the amps, but it's lists as an XT for the right years. Is this what you're talking about?

https://www.ebay.com/itm/2003-05-Subaru-Forester-XT-2-5L-Alternator-PN-23700AA370/173541124660?hash=item2867db6a34:g:hSYAAOSwQh1boCLP:rk:3f:0

Or anything that's listed for an '04-'08 XT?

Also, thanks for the advice about the wires. I measured each strand with a caliper, so I can use any single strand that's equal to the two added together, if that's what I can find?

Again, I really appreciate the fast responses.

 

[Scotty_B]

P.S.

I really don't mind doing the maintenance on this older Forester, but sometimes I feel like the little boy holding back the leaks in a ****!

 

[Kevin]

While you're at it I would add extra earth cables from the body to the engine - I have two 4 gauge (I think) with one attached to the top of each strut tower.

 

[2.5x_sleeper]

Bobby,

This doesn't list the amps, but it's lists as an XT for the right years. Is this what you're talking about?

https://www.ebay.com/itm/2003-05-Subaru-Forester-XT-2-5L-Alternator-PN-23700AA370/173541124660?hash=item2867db6a34:g:hSYAAOSwQh1boCLP:rk:3f:0

Or anything that's listed for an '04-'08 XT?

Also, thanks for the advice about the wires. I measured each strand with a caliper, so I can use any single strand that's equal to the two added together, if that's what I can find?

Again, I really appreciate the fast responses.

No need to be that precise on the wire gauge, just get the same or larger.

That eBay alternator looks like it's off an '04-'05 XT & should fit. It has some aluminum oxidation, which is normal.

P.S.

I really don't mind doing the maintenance on this older Forester, but sometimes I feel like the little boy holding back the leaks in a ****!

Older vehicles will require maintenance. If well maintained, they can last a long time... or until you get tired of it. :wink:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]