Never saw an alternator do this before.
10-11-2016, 12:11 AM
#1
Never saw an alternator do this before.
Sunday night I decided to go for a spin to see if the headlights seemed like they were aimed correctly, prior to this only one worked at a time. So maybe having both work was extra strain on an old alt, but I took off, the belt squealed a little which it always does when not fully warmed up (I know I need to fix that!) but this time the squeal was accompanied by the alt warning light, which then stayed on.
I pulled over and checked the belt which was fine and still on, restarted the car and light went off and the car was charging. Ideas? I've had alts die on me before, but never had one exhibit this exact behavior. I already sourced a replacement, I just want to learn what is going on here.
I pulled over and checked the belt which was fine and still on, restarted the car and light went off and the car was charging. Ideas? I've had alts die on me before, but never had one exhibit this exact behavior. I already sourced a replacement, I just want to learn what is going on here.
10-11-2016, 08:56 AM
#2
Melting Slicks
when alternator voltage drops below battery voltage the light will come on. its possible the alternator pulley is worn and the belt is not engaging it enough and slipping all the time or at higher rpms or the belt is worn. time for a new ones.
Last edited by speedreed8; 10-11-2016 at 08:58 AM.
10-11-2016, 12:21 PM
#4
Race Director
extra load caused the belt to slip, or a dirty belt. A slipping belt can "polish " the pulley + glaze the belt causing more slip. Sand paper the pulley and put on a new belt.
10-11-2016, 12:26 PM
#5
Melting Slicks
10-11-2016, 12:56 PM
#6
Team Owner
Some time ago the V belts became made to a METRIC base, the pitch of the V changed, from the old cars we knew....the V is more wide and so the metric belts ride on the top of the V and cause the back side to ride lo in the pullys the backside get worn on the edges, and get a U shape to it eventually.....
I have to specifically ask/demand an old AMERICAN style belt...
that was one reason I switched over to a serp drive on my '72 vette....
I have to specifically ask/demand an old AMERICAN style belt...
that was one reason I switched over to a serp drive on my '72 vette....
10-11-2016, 01:24 PM
#7
Melting Slicks
Is your belt configuration correct? I had belt squeal on starting when I first got the vette, I tried a new belt and that helped a little but eventually I learned that the belt routing was incorrect. The alternator was being driven directly from the water pump meaning the the crank pulley to water pump belt was taking the full load of the water pump, alternator and power steering pump, once I changed it to the correct routing shown in the AIM no more squealing.
10-11-2016, 02:42 PM
#8
Thanks for the replies, I will double check the routing. All the belts are new, the alt belt broke on me the day I bought the car and left me stranded 2/3s of the way home :P I am not sure if it is metric or not, switching to a serpentine setup at some point is on the radar, just need to learn some specifics for the swap.
The pulleys do all show the signs of just sitting unused with surface rust and I haven't driven the car enough yet to see if the new belts will polish some of that off.
What I was trying to get at was the cause of the intermittent light. Is it the slip causes low voltage>light comes on>slip stops but car must be shut down for warning light to reset?
In the past when I started it cold but did not pump the gas so it BARELY started and idled super low and the alt light came on, I blipped the gas and the light went off, so that leads me to think it does not need to be shut down and restarted to reset the light.
The replacement is cheap and its an easy swap so I will probably do that and keep the original as a spare either way.
The pulleys do all show the signs of just sitting unused with surface rust and I haven't driven the car enough yet to see if the new belts will polish some of that off.
What I was trying to get at was the cause of the intermittent light. Is it the slip causes low voltage>light comes on>slip stops but car must be shut down for warning light to reset?
In the past when I started it cold but did not pump the gas so it BARELY started and idled super low and the alt light came on, I blipped the gas and the light went off, so that leads me to think it does not need to be shut down and restarted to reset the light.
The replacement is cheap and its an easy swap so I will probably do that and keep the original as a spare either way.
10-11-2016, 03:48 PM
#9
Burning Brakes
belts are still made in SAE spec. Gates Super HC, Hi Power II, Tri-Power V, and others are inch. Metric power or other series are in MM, you just need to buy the correct belt, not some off the shelf universal belt that is the same length.
A series are 1/2", 5v is 5/8", SPA or XPA are 13mm, which is not a proper substitute as Mr vette eluded to.
you can spec out the proper belt and order from a true belt supplier rather than the local parts junk store...and a hardware store furnace belt is not the same thing, nor is a mower belt--I've seen people use those many times with little success...
A series are 1/2", 5v is 5/8", SPA or XPA are 13mm, which is not a proper substitute as Mr vette eluded to.
you can spec out the proper belt and order from a true belt supplier rather than the local parts junk store...and a hardware store furnace belt is not the same thing, nor is a mower belt--I've seen people use those many times with little success...
10-11-2016, 03:57 PM
#10
Team Owner
You can get the correct belts from a vendor on the Corvette Forum, or you can order over the internet from RockAuto.com.
Use 100 grit wet/dry sandpaper to clean off/scuff-up the groove faces of the pulleys on your car. Then install the correct belts and you should be good to go. Your problem was almost assuredly the alt belt slipping due to added alternator load after start-up. If you still have problem after 'dressing' pulley grooves and installing proper belts (which I doubt will be the case), let us know and we will re-think the issue.
Use 100 grit wet/dry sandpaper to clean off/scuff-up the groove faces of the pulleys on your car. Then install the correct belts and you should be good to go. Your problem was almost assuredly the alt belt slipping due to added alternator load after start-up. If you still have problem after 'dressing' pulley grooves and installing proper belts (which I doubt will be the case), let us know and we will re-think the issue.
Last edited by 7T1vette; 10-11-2016 at 04:01 PM.
10-11-2016, 04:04 PM
#11
I just went with a FLAPS belt and trusted in their computer system. I know I know, it usually works out alright, and in this case may still be fine, could just be a lack of tension.
I think I have all of the packaging from the new belts as I reused them to store the old belts for an emergency roadside fix so I can check exactly what I have. The inside of the car looks like a hoarder lives there with all the extra this and that floating around
I think I have all of the packaging from the new belts as I reused them to store the old belts for an emergency roadside fix so I can check exactly what I have. The inside of the car looks like a hoarder lives there with all the extra this and that floating around
10-11-2016, 11:31 PM
#12
Team Owner
Just inspect the sides of the belt in question. If it is contacting only a portion of the face, then the "V" angle on the belt is wrong for your pulleys. Added tension won't help, if it has the wrong style belt on it.
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shok (10-12-2016)
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shok (10-12-2016)
10-12-2016, 02:24 AM
#14
I had a belt squeal right after I fired up my newly rebuilt 454. It was the alt. itself. I removed the wire from it and it quit.
I even changed the belt as I was attempting to diagnose this.
Just another situation to consider, if not now, for the future
I even changed the belt as I was attempting to diagnose this.
Just another situation to consider, if not now, for the future
10-12-2016, 06:23 AM
#15
Melting Slicks
Check the alternator too for bad bearings. It should spin freely and smoothly
10-13-2016, 01:29 PM
#17
Burning Brakes
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I had that happen once. Alt seemed to work only at low RPMs and red light at higher RPMs. I would back off and the alt would work again. I tightened the belt and traveled on. The alt stalled because the belt was slipping. Did it at higher RPMs because of the demand.
Lots of good advice, especially removing the glaze on the pulley.
All worked well after that for years so I guess I was lucky the alt was not bad.
Dom
Lots of good advice, especially removing the glaze on the pulley.
All worked well after that for years so I guess I was lucky the alt was not bad.
Dom
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shok (10-13-2016)
10-13-2016, 05:10 PM
#19
Melting Slicks
I agree with jb78L-82, bad bearings, will lock up in time. cheap and easy to rebuild alternator with all new brushes, bearings etc.
Last edited by lvmyvt76; 10-13-2016 at 05:10 PM.
10-13-2016, 07:38 PM
#20
Well I have a rebuilt one sitting in a box now waiting to go on, family emergency will prevent me from installing it this weekend but maybe the following.
With its freshly painted pulley it should be easy to see the wear pattern to get an idea of the belt is correct.
With its freshly painted pulley it should be easy to see the wear pattern to get an idea of the belt is correct.
