I'm going to replace the alternator in my van. It appears to be the original, and according do the RPO code, it's 105 amp. RA has a 145 amp for a similar price. Any downsides/modifications or can I just swap it out?

 

the engine should be able to handle it just fine. Make sure the alternator cables and fusible link are rated for the higher current.
Try to stick to OEM brand alternators.

 

Rather than cross-post/double up: here is my post on similar topic:
https://chevroletforum.com/forum/exp...rnator-104725/

Definitely upgrade the "Big Three" wires too.

Cheers - Jim

 

Found this on RA:

https://www.rockauto.com/en/moreinfo...t=2500&jsn=779

Appears to be the same for both alternators. I'm wondering if they made only 1 cable for both alternators - the GM Parts site lists only this same part number for my vin:

https://www.gmpartsdirect.com/oem-pa...cable-84090494

I have no problem upgrading the cables if necessary, just don't want to buy them if I don't have to.

 

https://www.bluesea.com/resources/1437

 

That's a handy chart, thanks for the link.

I just looked at the cable on my van. It appears to be the factory cable and has a factory collar on it that says "22777071 GM Part Number". When I look this up, it brings me to the link I posted previously:

https://www.gmpartsdirect.com/oem-pa...cable-84090494

In this description, it says that it replaces the part number I have. So either the cable I have is for both 105 & 145 amp alternator options, or the new part number is a larger cable that covers up to 145 amp. Perhaps there were 2 different cables in 2013 and now they only offer the larger one?

I have zero hesitation replacing the cable if I need to, I just don't want to replace the cable if it's already the right one.

 

I couldn't tell ya. Like I said, just make sure it's sized for the current. Is the wire gauge stamped on the jacket?

 

Update:

I completed the alternator upgrade from the stock 105 amp(K68) to the larger 145 amp(KG3). I ordered everything from Rockauto. I had to replace the serpentine belt, alternator, and positive battery cable. I used all GM OEM parts as I have never found it worth the hassle or unreliable quality of cheap parts. This appears the be the stock alternator at 200k miles. I've been noticing some charging irregularities and just decided to change it instead of waiting until it dies and having to choose between spending twice the price at the dealership or buying foreign junk at the parts store. Overall the project took me about 3 hours (with distractions) but was very simple and straight forward. Also took the opportunity to take apart the MAF and clean it. This is not a remotely difficult or complicated job. The entire time I've had this van (40k miles/3 years) the alternator gauge on the dash has always sat right at 15 volts. It's now sitting right at the charging voltage shown on my multimeter at the battery terminals. My digital USB charging port also displays the same voltage as my multimeter, instead of sitting at it's standard 14.7 volts. Not sure if this is even relevant, just an observation.

These are not referral links, just links to the parts on RockAuto:

Alternator

GM OEM 22781131 145amp alternator (KG3) - $192.79

The stock 105 amp alternator (K68) is $180.89, about $12 cheaper than the upgrade. The RockAuto description for the 145amp alternator says "Use W/ 98057284 PULLEY FOR BELT LINE-UP". I looked up this number and it took me to a smaller idler pulley which I also ordered. However, when I installed it, it does not sit flush against the engine. It has a raised lip that is thicker than the stock pulley. This also keeps the bolt from going very far into the mounting bracket. When I installed the belt with the smaller pulley, the belt laid very close (1/8") to the alternator bolt. I was not comfortable with any of this so I put the stock size back on and it works just fine. There is still enough play in the tensioner to get the belt on/off. The stock pulley also brings the belt about 3/8" away from the alternator bolt and everything lines up perfectly. This alternator part number is the only one that says to use the smaller idler pulley. Even the ACDelco 145amp alternator does not require this smaller idler pulley. I'm not sure if this is a mistake on RockAuto's end or if there is indeed some engine variant that requires the smaller pulley.

Belt

Gates K060930HD FleetRunner Heavy Duty - $34.99

The belt for the stock 105amp (KG3) alternator is 92.34" long and the belt for the 145amp (K68) alternator is 93.02" long, a difference of a little shy of 3/4". The price difference is $0.20.
These FleetRunner belts are badass, very high quality. Not much of a price difference but a much better and more reliable belt. Belts are another item I do not pinch pennies on - the savings is never worth it when it lets you down.

Battery Cable

GM OEM 84090494 Positive Battery Cable/Harness for 145 amp (KG3) option - $86.89

This cable is definitely a larger gauge than the stock cable. GM only lists this cable for all models now, it appears they have discontinued the smaller version that came on the van from the factory. I may have been able to have cables made slightly cheaper locally but for me the likely small price difference wasn't worth the time/hassle of finding a local place and sourcing the proper fusible links. This one is a direct, easy replacement.

Total cost was $314.67 (+about $24 for shipping) for the upgrade.

Replacing with the 105amp stock alternator would have cost $180.89 (+about $12 shipping)

For about $135 I now have the 145amp alternator, proper wiring, and new serpentine belt.

 

nice work.
what kind of irregularities?

 

I made this thread a while back. In short, the entire time I've had the van it's stayed consistently at 14.5-14.7 volts on my digital gauge. It started fluctuating a while ago and has been inconsistent since. Plus the windows are slow and the headlights dim whenever I use them. It has a new battery and all connections are clean and good. Making a long trip this weekend, didn't want any problems. Plus I'm planning on adding an electric hoist/lift in the future, hence the upgrade.