How do I identify what alternator I have in a '04 Yukon Denali

[NELLY1947]

I have a 2004 Yukon Denali 6.0 and it has an Delphi alternator I believe stock OEM and I can't tell if it's 105 or 135 amp alternator.

How do I identify what size I have so I can get the right alternator I ordered a 105 amp alternator from Amazon it's the AC Delco Gold but I'm not sure if it's going to fit. The alternator is having bearing noises but it works so I was going to replace it because of all the noise the bearing makes.

I want to make sure it fits the the belt size that's already in there cuz the belt is still good

Call a dealer with you S/N it was on the build sheet.

 

[Fless]

Some RPO codes:

K68 = 105a generator (alternator)
KG3 = 145a "
KG8 = 130a "

 

[Doubeleive]

No, none of that. You're just guessing. That would require the tiniest battery and undersized alternator with additional loads that are too much for the stock electrical.
Electrical/THE LOADS, are a pull (what they need, not a push from the battery).


OP
The factory cable from alt to batt + is a fusible link. It is sized for the factory size alternator. If it has too much amperage/resistance then it is designed so that it will burn and break inside the casing, but the case/sheathing will stay intact, in order to prevent a bare wire from connecting off the amp to metal, arcing, and burning your pickup to the ground.
If you're going to upgrade your alt to something larger, you would need to upgrade the charging cable to get the benefit. You would then fuse that cable, and you would want a protected fuse holder.


The cable can be as large as you want. The fuse on the cable, needs to be less than the cable's capability. The point of the fuse is to intentionally create a weak point, that can be controlled, and easily fixed.


I'm mostly pickups, but there are two sizes of alternators, 105 and 130. 105 is a small case, and 130 is the large case. The 130 large case is also, 145, 160, 180, and just about everything else aftermarket. The shape of the two alts are different, and the pulley is in a different spot. The large case uses a serpentine belt that is 3/4" longer than the 105 amp small case. The smaller belt will physically install, on the larger case alt, but will cause more pressure on the alternator, and leads to: hard starting, whining at higher rpm, belt slipping at higher rpm, and poor charging issues. THIS is really why you need to know which alt you have. Personally, you should take the time to find the part number on the belt, and if you wanted, you could always see how to test the output on the alt if you didn't buy it, or own the vehicle since new.
105 came on 99-04, and then in 05 they went from clutch fan to electric fans, and needed a larger 130 amp alt, (might be a little higher on SUVs, the 3 digit K code in the glove box should be your alt size). If you are having bearing noises from the alt, someone may have previously upgraded the alt and not the belt. Replacing the belt to the correct size might solve your problem and be cheaper.

Unless you have aftermarket amps for subs, or have larger draw items in your vehicle like a fridge, or a pump, there's almost no other reason to need a larger alt than factory. If you're not getting voltage drops, then you have all you need.

well I am speaking in regards to a system being under a load, my 2012 came stock with a 160a alternator, I have upgraded it to a 250a and loaded the system to a confirmed 240amp load with a dc clamp meter, so under that load with a 160a alternator I would have experienced system degradation, such as electrical spikes, light dimming, etc.
so while my statement is "speculation" it is based on reality, it may not be something you could see with your eyes but would show on a scope/meter, no "guessing" involved.
it's all based on the load on the alternator

 

[justirv]

No, none of that. You're just guessing. That would require the tiniest battery and undersized alternator with additional loads that are too much for the stock electrical.
Electrical/THE LOADS, are a pull (what they need, not a push from the battery).


OP
The factory cable from alt to batt + is a fusible link. It is sized for the factory size alternator. If it has too much amperage/resistance then it is designed so that it will burn and break inside the casing, but the case/sheathing will stay intact, in order to prevent a bare wire from connecting off the amp to metal, arcing, and burning your pickup to the ground.
If you're going to upgrade your alt to something larger, you would need to upgrade the charging cable to get the benefit. You would then fuse that cable, and you would want a protected fuse holder.


The cable can be as large as you want. The fuse on the cable, needs to be less than the cable's capability. The point of the fuse is to intentionally create a weak point, that can be controlled, and easily fixed.


I'm mostly pickups, but there are two sizes of alternators, 105 and 130. 105 is a small case, and 130 is the large case. The 130 large case is also, 145, 160, 180, and just about everything else aftermarket. The shape of the two alts are different, and the pulley is in a different spot. The large case uses a serpentine belt that is 3/4" longer than the 105 amp small case. The smaller belt will physically install, on the larger case alt, but will cause more pressure on the alternator, and leads to: hard starting, whining at higher rpm, belt slipping at higher rpm, and poor charging issues. THIS is really why you need to know which alt you have. Personally, you should take the time to find the part number on the belt, and if you wanted, you could always see how to test the output on the alt if you didn't buy it, or own the vehicle since new.
105 came on 99-04, and then in 05 they went from clutch fan to electric fans, and needed a larger 130 amp alt, (might be a little higher on SUVs, the 3 digit K code in the glove box should be your alt size). If you are having bearing noises from the alt, someone may have previously upgraded the alt and not the belt. Replacing the belt to the correct size might solve your problem and be cheaper.

Unless you have aftermarket amps for subs, or have larger draw items in your vehicle like a fridge, or a pump, there's almost no other reason to need a larger alt than factory. If you're not getting voltage drops, then you have all you need.

Thanks Adriver, great, detailed, explanation.