Alternator Identification

[scottinaz]

Ok, since I bought my exploder, the charging voltage has been a bit lower than I would prefer, say around 13.5ish volts. Last night driving home, I was getting lower voltage, around 12.5 or lower when idling, but would come up when off idle and actually driving. Im thinking the alternator is packing it in (ill check the fuses tonight).

Main question is this. Rock Auto lists a 95 amp and a 130 amp alternator. What is the easy way to distinguish between the two, and hopefully, ARE THEY INTERCHANGEABLE?

Would prefer the larger of the two, as its a Bauer and has all the electrical doo-dads on it that suck amperage. The truck has an autozone alternator on it now, and it doesnt appear that old, but if the PO put the small capacity amp in it (cheaped out), that could be the cause of the whole low voltage thing.........

What say all Y'all

 

[BruceExploder]

Yes putting a 135 amp is fine

 

[donalds]

What engine do you have

 

[scottinaz]

What engine do you have

it has the 4.0 SOHC devil motor.

 

[donalds]

130 amp

 

[scottinaz]

Ok, given a choice, I WANT the 130 amp unit, but is there a way to identify what is currently installed? I show both as available to fit the motor. Given the history I have with the truck, the PO tended to cheap out on parts. (Brakes completely FUBAR when purchased, etc.....) I would hate to waste time chasing a gremlin only to find an underspec alternator was installed.

 

[scottinaz]

ok, just got done looking at the darn thing, and it appears to be a 130 amp unit on there. Downside though, its a Duralast DL3405-16-2, which appears to be the bottom of the barrel discontinued (read out of any kind of warranty) POS reman. Ill have to do a bit more digging on it, along with checking the usual suspect connectors, but Im thinking that its starting to pack it in. Bugger. damn things are expensive.......

 

[CDW6212R]

That Eddie Bauer model will need the bigger alternator, I thought 140 was the rating.

The 4.0 SOHC uses the same 4G unit as the 302 trucks, so either ask for one for a Limited, or hunt a used truck like them as they aren't cheap, new.

 

[J_C]

?? Unless it has a factory subwoofer, cranked up, a 95A alternator should be plenty to merely keep the voltage at 14.4V at idle, even with the headlights on. The other electrical upgrades on an EB, aren't drawing much current unless you're trying to operate every window motor with the fog lights and wipers all on simultaneously.

At the same time, that's more stress on it and I too would prefer the higher capacity alternator when the price difference isn't much, but the point is an inexpensive reman alternator may have a shorter lifespan than new OEM and the vehicle is now ~22 years old. How old is that alternator?

I did gamble myself and get a reman 130A at Advance Auto, but I had a $40 off coupon code (ordered online for store pickup to use the coupon code) and it has a lifetime warranty. It was $147 at the time and now $156, before the $40 off.

I faced a different situation than some, that even buying a new alternator it might have only had a two year warranty and I'm barely putting any miles on my '98 XLT, so in two years I would have barely gotten any use out of it, and where do I pay to ship the thing to for warranty replacement if bought online at Rock Auto? The lifetime warranty from an Advance Auto Parts store 2 miles up the road was the trade off I made, and I made sure to make a scan of the receipt since their purchase tracking system isn't as good as that at Autozone and some receipts tend to have ink that disappears over time. Some things I have bought with a lifetime warranty, changed to a shorter period (in their system too) so you need the receipt that states lifetime warranty... like my Autozone !@#$ hood struts that have failed at least 6 times (last about 2-3 years per pair), and their lifetime warranty on them bought new ended over a decade ago.

Anyway here's the 130A one at Advance Auto I bought a little under 4 years ago (wow time flies!), you could look around for any coupon codes floating around the internet.

Advance Auto Parts - Down for Maintenance

 

[scottinaz]

I honestly have no idea how old the reman is that is on there, the part number has been superceded at least 2x on the Autozone site, and it only had a 1yr warranty on it anyways. The truck is equipped with a subwoofer, but I dont blast it anyways. I just noticed that the needle on the voltage gauge was a bit lower than normal, and my bluetooth code reader confirmed the voltage at ~12.2 at idle, going up to 13.1 and rising as I drive. Tells me that the alt isnt keeping up with the load of the headlights/basic systems/stereo at idle. When I got it home, and turned off the lights, I got 12.8 or so at idle, and 13.5 or better when revved up to 1500-2000 rpm. Ever since I got the truck about a month ago, its been charging, but a bit lower in voltage than I would prefer (14.5 or so is my happy place), but I accepted that the regulator may just have a lower set point than another regulator (not a big deal, as long as it can be maintained). I was a bit concerned with possibly having a lower amp alternator, as that would be a simple gimme in that a lower than specified output would be taxed more than a higher rated one with the same accessories on, and therefore an easy target for replacement/upgrade. before condemning the alternator ill be checking all connections and the system grounds, as that can obviously affect the output voltage that the system sees as well as adding load to the alternator, prematurely killing the damn thing.

 

[J_C]

Cleaning the alternator cable at the alternator and the battery terminal connections is definitely something to look into (easy and free) but odds are the alternator is just dying.

Whether it was 95A or 130A, it worked up till now, right? You didn't install some new power hungry electrical equipment to put an extra load on it?

However an old battery that doesn't hold a charge well is also hard on an alternator, especially if the battery has a cell shorted out. I would put a charger on it for a while, disconnect charger and see if it's getting to near 12.6V instead of only 10.4V (a sign a cell is shorted).

A battery with one cell gone can kill an alternator so you want to make sure you're not putting a new alternator in with a bad battery.

 

[scottinaz]

battery is relatively new, and holds a charge good. No new accessories added since I got it.

 

[donalds]

How to: - 4g alternator rebuild with pictures

 

[CDW6212R]

How to: - 4g alternator rebuild with pictures

Super thread, that will help a bunch of people.

 

[reansor]

I'm not sure if you're running a lot of extra accessories, but the voltage you spec'd sounds like it's about right where it should be.

 

[J_C]

^ Stock voltage with the engine running and a reasonably charged battery should be closer to 14.4V.

 

[CDW6212R]

If the running voltage drops below about 13v, then the alternator is working very hard, or over taxed. Seeing close 14.5v means the battery still needs some charging, and as it nears being completely full, the voltage might end up nearer to 14.0 volts, such as on a long trip.

 

[dwitte]

Ok, since I bought my exploder, the charging voltage has been a bit lower than I would prefer, say around 13.5ish volts. Last night driving home, I was getting lower voltage, around 12.5 or lower when idling, but would come up when off idle and actually driving. Im thinking the alternator is packing it in (ill check the fuses tonight).

Main question is this. Rock Auto lists a 95 amp and a 130 amp alternator. What is the easy way to distinguish between the two, and hopefully, ARE THEY INTERCHANGEABLE?

Would prefer the larger of the two, as its a Bauer and has all the electrical doo-dads on it that suck amperage. The truck has an autozone alternator on it now, and it doesnt appear that old, but if the PO put the small capacity amp in it (cheaped out), that could be the cause of the whole low voltage thing.........

What say all Y'all

See the attached pictures. The 130 amp has TWO holes at the end of the red arrow. The 95A has FOUR holes.

 

[Mbrooks420]

The stock subwoofer will not draw any appreciable power. I think unless it was a very stripped out model it has the 130 amp alternator. All three of mine have had it.