Very hot alternator
Thread Starter
6th Gear
Joined: Oct 2014
Posts: 6
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From: Nova Scotia
Very hot alternator
Question re alternator heating up. Just how hot does your alternator get? Mine gets so hot can't touch. Recently had an intermittent problem with gauges showing alternator wasn't charging however had it bench tested and ok. I realize bracket for alternator is attached to the block so must get some heat transfer. Does anyone with another C5 2000 want to start your car and check the heat? Thanks guys and gals.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You can check the charging voltage by measuring the battery terminal and measuring the BATT terminal on the back of the alternator to chassis ground.
You need to go to a shop to have the charge current tested . If the output is normal, I wouldn't much worry about it.
Can you use a inferred thermometer and get the exact temp?
Bill
You need to go to a shop to have the charge current tested . If the output is normal, I wouldn't much worry about it.
Can you use a inferred thermometer and get the exact temp?
Bill
Thread Starter
6th Gear
Joined: Oct 2014
Posts: 6
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From: Nova Scotia
Thank you all for your input. I have measured the voltage at the battery and it runs between 13.5 to 14.2 with car running which I understand is normal. I shall see if I can get the temp of the alternator housing.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
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From: Columbia SC
If you do decide you have an issue with alternator, DO NOT turn in your core until you have a good functioning replacement. The C5 ones are unique and have an interface with the PCM.
Many people have had replacement issues and ended up rebuilding their originals.
Many people have had replacement issues and ended up rebuilding their originals.
Thread Starter
6th Gear
Joined: Oct 2014
Posts: 6
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From: Nova Scotia
Again thanks for the input. A couple of questions.
1. Took the car into dealer. They did a charge system check. Told me the battery cracking power failed, 400 instead of 800. Sold me a new battery. It's still not right. I had changed the voltage regulator on the alternator but got low readings on gauge in car, 12.5 to 13.1. So we decided to put back the original voltage regulator.
2. I measure the voltage at the battery with car idling and it is 13.9v then I measure the large red wire at the alternator to ground and I get 15.01 v. Is that too high?
It seems the output from the alternator is at least 1 volt more than at the battery and yet they are directly connected thru the starter. Any comments are appreciated.
Richard
1. Took the car into dealer. They did a charge system check. Told me the battery cracking power failed, 400 instead of 800. Sold me a new battery. It's still not right. I had changed the voltage regulator on the alternator but got low readings on gauge in car, 12.5 to 13.1. So we decided to put back the original voltage regulator.
2. I measure the voltage at the battery with car idling and it is 13.9v then I measure the large red wire at the alternator to ground and I get 15.01 v. Is that too high?
It seems the output from the alternator is at least 1 volt more than at the battery and yet they are directly connected thru the starter. Any comments are appreciated.
Richard
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Thread Starter
6th Gear
Joined: Oct 2014
Posts: 6
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From: Nova Scotia
I did a voltage drop test between the alternator B+ and the + side of the battery. Voltage drop of 1.4 volts with heavy load, lights, radio, heat, and revs at 2000. I've read that should only be .2 or .3 at most. So the only connection between those 2 points is indeed the connection at the solenoid. I shall have the dealer put it up on a hoist and check it out.
R
R
Race Director
Joined: Apr 2007
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From: South Western Ontario
If you're paying to get it checked, also clean the connection on the back of the alternator and check fusible link on the end of the alternator wire at the solenoid and check the battery cable out too to ensure that the wires look OK.
My car started to show voltage drops like that and it was the solenoid connections. Now I have 14.2-14.3V at the battery all the time.
My car started to show voltage drops like that and it was the solenoid connections. Now I have 14.2-14.3V at the battery all the time.
Thread Starter
6th Gear
Joined: Oct 2014
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From: Nova Scotia
Had the car on the hoist at the dealer and the connection on the solenoid was indeed loose. Cleaned it and after tightening, all is well. 14.2 volts, voltage drop is now .3 volts. Hopefully that's a wrap.
One question however. Does the red wire from the alternator go to the solenoid and from there to the battery? That's what I understood however in the schematic there is a dotted line after the fusible link to the starter. Tech told me the wire from the alternator goes directly to the battery. Can't be so.
One question however. Does the red wire from the alternator go to the solenoid and from there to the battery? That's what I understood however in the schematic there is a dotted line after the fusible link to the starter. Tech told me the wire from the alternator goes directly to the battery. Can't be so.
Drifting
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From: cinnaminson n.j.
St. Jude Donor '14
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Had the car on the hoist at the dealer and the connection on the solenoid was indeed loose. Cleaned it and after tightening, all is well. 14.2 volts, voltage drop is now .3 volts. Hopefully that's a wrap.
One question however. Does the red wire from the alternator go to the solenoid and from there to the battery? That's what I understood however in the schematic there is a dotted line after the fusible link to the starter. Tech told me the wire from the alternator goes directly to the battery. Can't be so.
One question however. Does the red wire from the alternator go to the solenoid and from there to the battery? That's what I understood however in the schematic there is a dotted line after the fusible link to the starter. Tech told me the wire from the alternator goes directly to the battery. Can't be so.
You CAN run a wire directly fron the alternator to the battery but it needs to be fused and you would also need to run a feed back wire to the battery.