Think my alternator finally took a s***

[jiggletits]

273k miles on the original alternator. Battery is from 2019 and hasn't had any issues prior to last week.

I left town over the holidays, did not start the GX for maybe two weeks? It was a little cold while I was away. On return, the truck would not start. I put it on an 8 amp smart charger for about 24 hours and it did not hold voltage. 10V before and after. Next step; I jumped it off my Tundra and it was fine for a couple days.

One cold morning while driving it the battery light came on so I drove straight home and parked it. That was the first time I ever saw the battery light on. I also noticed the stereo all of a sudden sounded like s***, like it wasn't getting power.

The truck would not start again today, so I jump-started it to troubleshoot and it was getting 9.8 volts at idle. The battery light was not on. It still only ever came on once and it did not stay on.

What seems odd is that the battery light did not come on sooner, and I guess that is my only reason for this post. Is that normal? Does voltage really need to drop that low before the light comes on? I have an OEM alternator on order and am hoping I can still use this battery after recharging it.

 

[HomersCanyonero]

A while back I inquired about how alternators fail. You have the symptoms that people described. You can get electrical gremlins when the alternator is failing and also won't charge your battery. I replaced my alternator as a preventive maintenance because I didn't want what you describe to happen to me when I'm off grid.

In terms of when the lights get triggered due to low battery, I don't know about that. I just hope your battery has a 36-month free replacement warranty. Most batteries seem to have that at least when I buy at Costco or AAA. That would be a good use of the warranty rather than trying to revive the one you have.

 

[jiggletits]

Thanks, yeah I am certain it's a bad alternator. Just surprised the light isn't on. That's a dead giveaway on every other vehicle.

 

[sshevela]

Check the voltage at the battery when its running.

If it isnt sitting over 12v and holding, bad alternator.

 

[Tanaman]

My alternator did almost the same thing. It randomly decided to die one day with only a very short notice by the battery light. Sadly I had just done the TB/WP and such only weeks before so I had to go back in and do it. Word to the wise, if you’re doing your TB/WP check that alternator so you don’t have to do it twice like me

 

[markthegrea]

I just replaced my alternator ($500 with labor).

I have a USB bluetooth dongle that shows the voltage at startup (usually around 14volts). The other day, and only when at idle, it would start blinking and show 10.1, 9.8, 9.2 etc. When I reved the engine it went back to normal. During normal driving, it was normal. I took it to the mechanic who tested it before replacing it and got a call: "Hey, it looks ok". I told him my experience and, yep, after it warmed up he reproduced the problem.

So, buy a cheap bluetooth dongle and test your electrical system!

 

[HomersCanyonero]

I just replaced my alternator ($500 with labor).

I have a USB bluetooth dongle that shows the voltage at startup (usually around 14volts). The other day, and only when at idle, it would start blinking and show 10.1, 9.8, 9.2 etc. When I reved the engine it went back to normal. During normal driving, it was normal. I took it to the mechanic who tested it before replacing it and got a call: "Hey, it looks ok". I told him my experience and, yep, after it warmed up he reproduced the problem.

So, buy a cheap bluetooth dongle and test your electrical system!

That’s good to know. I have the Bluetooth odb2 adapter and the CarScanner paid app. I’ll check the voltage at idle

 

[McDuff123]

273k miles on the original alternator. Battery is from 2019 and hasn't had any issues prior to last week.

I left town over the holidays, did not start the GX for maybe two weeks? It was a little cold while I was away. On return, the truck would not start. I put it on an 8 amp smart charger for about 24 hours and it did not hold voltage. 10V before and after. Next step; I jumped it off my Tundra and it was fine for a couple days.

Strange that the battery didn’t hold a charge after a long session with the smart charger…a failing alternator shouldn’t affect that, should it?
You sure it’s not the battery?

 

[jiggletits]

Fellas thanks for the replies, but all I am wondering why the battery light was not on with 9.8 volts at the battery and the vehicle running.

 

[jiggletits]

Well the alternator is a rather foul whore to get off with my large arms and hands. Had to remove the fan/shroud/radiator hoses to get the power steering pulley off, wouldn't budge especially with 1" of clearance. Bad design accessing the alternator. This turned into a weekend project and I have half the parts removed already for access to the timing belt... might as well do that too.

I think the battery turned out to be okay after a few days on the charger, so saved some dough there.

 

[Tanaman]

You must be rather large because I’m not a small person by any means and I had no issue getting the alternator out and back in without pulling anything else. I guess it’s a good excuse to do the TB/WP though if you’re almost due for it.

 

[jiggletits]

You must be rather large because I’m not a small person by any means and I had no issue getting the alternator out and back in without pulling anything else. I guess it’s a good excuse to do the TB/WP though if you’re almost due for it.

I'm 5'-11" 195 lbs but with ape arms.

Were you able to get it out without removing the power steering pump or pulley? The PS pulley on mine is 100% blocking the alternator from sliding off the mounting studs. Alternator was completely disconnected and loose but I could not get that pulley off by hand.

Honestly though I gave it about 10 minutes effort then said f it, the timing belt is due. 273k miles and it'll be the 3rd timing belt. Water pump doesn't spin too great either so I'm glad I got in there.

 

[Tanaman]

Ape arms are good in many cases but not when it comes to wedging your self into tights spaces in a vehicle haha I’m 6’1” 240 so I definitely understand

Sounds like it’s best to just dig a little deeper and get all that work done anyways. I was able to loosen the power steering and get it out of the way so the alternator could just slide out. But I also did mine weeks after doing a timing belt service so i did the least I had to in order to get it replaced because I definitely didn’t want to do it all again.