Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.

New Posts Contact us

Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

Alternator smoking...

EYY

Well-Known Member
Joined
Mar 6, 2011
Messages
5,416
Reaction score
1,466
Points
113
Location
Vic
Members Ride
VS Statesman
Last night I was driving home and the battery light came on. Kept driving until there was somewhere to pull over and I then opened the bonnet to find smoke pouring out of the alternator! I disconnected the regulator and the main power wire and was able to make it the rest of the way home.

I went and bought another second hand alternator today and fitted it, and also put a new wire in that goes from the alternator to the battery. After running for only a couple of minutes, the new alternator gets too hot to touch.

Is this normal? How hot do they usually get?
Granted, it will be under a little load recharging the battery since I drove home with the lights running off the battery for 15km last night.

Thanks
 

deserthead

Well-Known Member
Joined
Oct 20, 2004
Messages
1,076
Reaction score
71
Points
48
Location
Cairns QLD
Members Ride
VS III l67 Column Shift Ute
What voltage you got across the battery when running?

That will give you an indication of whether it ok or not.

Could be working a little harder to recharge the battery, but mine runs hot too from heat soak from the engine.
 

junglecook

New Member
Joined
Sep 29, 2014
Messages
30
Reaction score
0
Points
0
Location
nsw
Members Ride
vs 5L
I may be wrong but I think the alternator would not carry any extra load due to a low battery because it would make no difference to the speed in which the belt is going, also the battery couldn't have been to low if it started the car.
 

EYY

Well-Known Member
Joined
Mar 6, 2011
Messages
5,416
Reaction score
1,466
Points
113
Location
Vic
Members Ride
VS Statesman
It has 13.9 volts across the battery and 14.0 at the alternator itself.

If anyone with a vs-vy could see how long it takes for the alternator to get too hot to touch, that would be great!

I'm worried that something isn't right. It takes about 2 minutes of it running to get really hot, after that I can't touch it at all. I'm supposed to be going on a bit of a trip for a few weeks beginning next week. Should cover about 6,000km all up so I don't want it catching fire or something :s
 

junglecook

New Member
Joined
Sep 29, 2014
Messages
30
Reaction score
0
Points
0
Location
nsw
Members Ride
vs 5L
I recently had a regulator on its way out on my vs 5.0 and did a lot of dicking around with it at running temperature and it was never crazy hot. Did you change the voltage regulator with the new alternator? Doing error check with a paperclip is always a good thing to do when stumped.
 

EYY

Well-Known Member
Joined
Mar 6, 2011
Messages
5,416
Reaction score
1,466
Points
113
Location
Vic
Members Ride
VS Statesman
Yeah did both of those things. I have another alternator that I'll put on tomorrow and see if it's any better. Fingers crossed!

Edit: just to update-changed alternators again and it fixed it!
 
Last edited:

Wozza

Well-Known Member
Joined
Dec 13, 2011
Messages
1,891
Reaction score
293
Points
83
Location
Adelaide
Members Ride
VR_GS commodore
Hi
Alternators get hot when your pulling big amps...a stock car will prob pull about 50 amps with everything on max maybe a little more...if you have a big sound system or a high resistance somewhere you might be pulling more than the alt can handle....leads can brake down internally causing high resistance or bad earths ect....if you have a lot of accessories Id suggest going up to 120 amp alt plus/or do the big 3 upgrade
 
Top