The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

**jocko** · 11-05-2017, 10:19 PM

Ok gents - revised my original post after I found out some additional info about my truck.

My truck came with a 105 amp alternator (RPO K68).
I recently installed a new alternator at about 250k mi.
It was dang near impossible to install the belt, thought maybe my tensioner had bit the dust, just couldn't seem to stretch that belt on (and I know I shouldn't have to, have replaced the belt many times in 250k mi). But, I got it on.

Since then, the alternator works fine, BUT:
- noisier than usual
- HOT to the touch for hours after shutdown
- faint smell, even 3-4 months after install, "kinda" electrical, or "kinda" belt slipping rubber smell, "kinda" oil smell. Weird... And my wife can't smell it at all.

My working theory, in hindsight, is that perhaps the counter dude gave me a 130 amp alternator, which requires a slightly longer belt - that would explain my difficulty getting the correct belt for a 105 amp alternator on there (I mean I almost gave up, assumed SOMEthing was wrong, but then finally got it on, and it worked, so I left it). And the added pressure on the bearing is making the alternator "that" hot, and causing the increased noise.

While I have the paperwork that showed me the RPO for the original 105 amp alternator, unfortunately I don't have the paperwork from the alternator I bought a few months ago... idiot..

Anyway (here it is finally, my question) -

Is there any way to tell visually tell whether an alternator is a 105 or 130 amp alternator? Anyone have both belt pulley measurements handy? (or even just one, if you happen to know which alternator rating you have - or just the measurement, even if you don't know its rating - with two different measurements from folks, can deduce the smaller is the 105 amp) That's the only thing I could think of to confirm. Any other ideas greatly appreciated - including thoughts on the overall weird situation. I'm hesitant to rip it apart since everything is working fine. But I also feel like I'm kind of just biding my time until the new alternator fails at the most inopportune time - due to excessive bearing load, or perhaps I'll smoke my smallest gage alternator wire because it's transporting 130 amps now. I don't know.
Thanks for the help.

11-05-2017, 10:19 PM	#1
jocko Senior Member Join Date: Oct 2009 Location: Godley, TX Posts: 17,934	2001 Z71/5.3 Alternator question Ok gents - revised my original post after I found out some additional info about my truck. My truck came with a 105 amp alternator (RPO K68). I recently installed a new alternator at about 250k mi. It was dang near impossible to install the belt, thought maybe my tensioner had bit the dust, just couldn't seem to stretch that belt on (and I know I shouldn't have to, have replaced the belt many times in 250k mi). But, I got it on. Since then, the alternator works fine, BUT: - noisier than usual - HOT to the touch for hours after shutdown - faint smell, even 3-4 months after install, "kinda" electrical, or "kinda" belt slipping rubber smell, "kinda" oil smell. Weird... And my wife can't smell it at all. My working theory, in hindsight, is that perhaps the counter dude gave me a 130 amp alternator, which requires a slightly longer belt - that would explain my difficulty getting the correct belt for a 105 amp alternator on there (I mean I almost gave up, assumed SOMEthing was wrong, but then finally got it on, and it worked, so I left it). And the added pressure on the bearing is making the alternator "that" hot, and causing the increased noise. While I have the paperwork that showed me the RPO for the original 105 amp alternator, unfortunately I don't have the paperwork from the alternator I bought a few months ago... idiot.. Anyway (here it is finally, my question) - Is there any way to tell visually tell whether an alternator is a 105 or 130 amp alternator? Anyone have both belt pulley measurements handy? (or even just one, if you happen to know which alternator rating you have - or just the measurement, even if you don't know its rating - with two different measurements from folks, can deduce the smaller is the 105 amp) That's the only thing I could think of to confirm. Any other ideas greatly appreciated - including thoughts on the overall weird situation. I'm hesitant to rip it apart since everything is working fine. But I also feel like I'm kind of just biding my time until the new alternator fails at the most inopportune time - due to excessive bearing load, or perhaps I'll smoke my smallest gage alternator wire because it's transporting 130 amps now. I don't know. Thanks for the help. Last edited by jocko; 11-05-2017 at 10:27 PM.