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Overheating Alternator

 
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EB XR8
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PostPosted: Wed Dec 01, 2004 10:46 am    Post subject: Overheating Alternator Reply with quote

f**k Electrical things!! I recently bought a brand new alternator as my old one s**t itself. The other day when i was driving i ntoiced the volts weren't as high as they usually are (it was displaying abour 12-13 volts). The charge light on the dash did NOT come on. When i pulled over to check it out the alternator was so hot i couldn't touch it for more than a millisecond (estimation). I am absolutely bamboozled. How can an alternator (especially one that is brand new) overheat?? I also think i could here a humming noise that sounded like a hydraulic pump that was low on oil. I checked the power steering and it was good. I am scared to drive now as i dont want to damage it.
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Disco Frank
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PostPosted: Wed Dec 01, 2004 10:54 am    Post subject: Reply with quote

mm that humming noise you speak of is when the alt is under load ie charging!
you hear it when u jump start your car and it has to charge a flat battery.
as for it gettign hot well it should get hot as the exhaust would radiate heat.
as for it not chargign on the dash get a multi meter out and put it on the batt terminals and look that way should be above 14volts the gauge in car could bea bit diccky
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EB XR8
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PostPosted: Wed Dec 01, 2004 10:59 am    Post subject: Reply with quote

Disco Frank wrote:
mm that humming noise you speak of is when the alt is under load ie charging!
you hear it when u jump start your car and it has to charge a flat battery.
as for it gettign hot well it should get hot as the exhaust would radiate heat.
as for it not chargign on the dash get a multi meter out and put it on the batt terminals and look that way should be above 14volts the gauge in car could bea bit diccky


I'll get a multimeter and try it out as my gauge could be d**k. As for the heat, i mean it was hotter than usual. My engine wasn't any hotter than normal so it shouldn't have heated up the alternator any more than normal. Is there any oil or something inside the alternator to help keep it cool?
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4.9 EF Futura
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PostPosted: Wed Dec 01, 2004 11:11 am    Post subject: Reply with quote

EB XR8 wrote:
Disco Frank wrote:
mm that humming noise you speak of is when the alt is under load ie charging!
you hear it when u jump start your car and it has to charge a flat battery.
as for it gettign hot well it should get hot as the exhaust would radiate heat.
as for it not chargign on the dash get a multi meter out and put it on the batt terminals and look that way should be above 14volts the gauge in car could bea bit diccky


I'll get a multimeter and try it out as my gauge could be d**k. As for the heat, i mean it was hotter than usual. My engine wasn't any hotter than normal so it shouldn't have heated up the alternator any more than normal. Is there any oil or something inside the alternator to help keep it cool?


Think they're just sealed bearings in there mate.
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Timboxrute
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PostPosted: Wed Dec 01, 2004 11:38 am    Post subject: Reply with quote

only has sealed bearing on one side other side is usually a slip ring design but under load they do get f**k hot check the belt tension as well asit could too tights and putting to much stain on that front bearing
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joolz
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PostPosted: Wed Dec 01, 2004 6:22 pm    Post subject: Reply with quote

it may not be the alternator, as you said the old one shat its self. the new one may do the same if you have a fault in the car somewhere, for it to get hot there could be a great load across it like a faulty battery, stuck starter soleniod. would test volts across battery when running after a short time then disconnect neg of battery and test again and also see if it still gets hot. could be a simple shorted plate in the battery.
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EBXR8380
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PostPosted: Thu Dec 02, 2004 12:29 am    Post subject: Reply with quote

Yep sounds like you have a massive short there some where??? Can you get your hands on a tong ampmeter to measure load on active battery cable??? Check cable to starter motor?? Is the wire from alternator getting hot ??? As above tension ???? Dry bearing ???
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EB XR8
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PostPosted: Mon Dec 06, 2004 5:27 pm    Post subject: Reply with quote

EBXR8380 wrote:
Yep sounds like you have a massive short there some where??? Can you get your hands on a tong ampmeter to measure load on active battery cable??? Check cable to starter motor?? Is the wire from alternator getting hot ??? As above tension ???? Dry bearing ???


I can buy a multimeter that should cover ammeter / voltmeter and whatever else they do. As for belt tension, i thought the serpentine belts on the E series V8's were self adjusting. (isn't that why they have the 3/8" part to put a ratchet in there to remove tension when replacing belts) Am I wrong??? It does sound like a dry bearing but as people said before, they are a sealed bearing and being a brand new alternator, shouldn't happen.
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joolz
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PostPosted: Tue Dec 07, 2004 6:43 pm    Post subject: Reply with quote

Multi meters only handle up to 10amps unless you go to an auto elec.
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Disco Frank
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PostPosted: Tue Dec 07, 2004 11:46 pm    Post subject: Reply with quote

nar u can buy these funky ones with inductive clamp that can do more!
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EBXR8380
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PostPosted: Wed Dec 08, 2004 7:25 am    Post subject: Reply with quote

Disco Frank wrote:
nar u can buy these funky ones with inductive clamp that can do more!

Yep or tong style where they open like a clamp...seperate from m/m...
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EB XR8
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PostPosted: Thu Dec 16, 2004 10:31 am    Post subject: Reply with quote

[quote="EB XR8"]
EBXR8380 wrote:
Yep sounds like you have a massive short there some where??? Can you get your hands on a tong ampmeter to measure load on active battery cable??? Check cable to starter motor?? Is the wire from alternator getting hot ??? As above tension ???? Dry bearing ???



I have since got the alternator replaced (under warranty) but i do think that there must be a short somewhere in my car. I have also replaced the battery. My question is, shouldn't there be a fuse or something that will cut out if there is a short???? My Voltage gauge jumps around a lot and the volts drop when the car is idling. However, the charge light does NOT come on and i know the bulb works for it too. Would it be dangerous (in terms of damage to the new alternator) if i drove it to an auto-electrician?? I notice you wrote check cable to starter motor. Could this be shorting against the body or engine???
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smoke_
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PostPosted: Fri Dec 17, 2004 10:00 pm    Post subject: Reply with quote

sounds like you have a bad earth, if your gauges are fluctuating or not reading right, check earths, check for damage to battery cables.
the battery symbol (charging lamp) should come on when you switch the key to ignition.
it then should go out when you fire the car over.

check for voltage drops between alternator and battery.
the way to do this is get one end of your multimeter and connect it to pos on alternator, and get the other end and connect it to battery positive.
if you have a reading of more than 0.2v, i'd think you would want to replace the alternator-to-battery cable.

Do this test also from the body of the alternator to the negative terminal.
once again, if you have anything over 0.2v, start to look further.

Also, if you want to get a total voltage drop, measure battery voltage, and then measure alternator voltage, and subtract.
you will then have total voltage drop.

hope this helps you solve the problem.
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joolz
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PostPosted: Sun Dec 19, 2004 11:45 pm    Post subject: Reply with quote

it may not be a dead short but maybe a component such as a diode gone to a parcial short, it could be drawing up to 20 amps without blowing a fuse. best thing to do is put ur amp meter on the pos battery cable and disconnect things such as alternator, radio, cig lighter and so on just to narrow it down, a simple way is to take out fuses as they tell you what they power and just remember to keep an eye on the amp guage before and after each fuse or part.
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