Alternator getting hot fast 01 c5
Thread Starter
Pro
Joined: Oct 2006
Posts: 585
Likes: 57
From: Toronto
Alternator getting hot fast 01 c5
My alternator stared to get hot really fast (within 60 seconds) then start to make a whine noise.
I had it checked by a shop he says its ok. I am using a deep cycle battery short term as my original is being used elsewhere.
The battery checks ok at home with tester but the shop wants me to do a load test on it he thinks this is why my alt is getting hot. I checked all the connections (good) even at the start solenoid (new within a month) the alt puts out 20 amps at idle when it is doing this.
I checked the power on the 3 wire connector at the alternator too. 9.7 volts on one red and 12 on the other.My deep cycle battery is a bit weak/old but it seems fine can a not 100% battery cause this? when i start the car the dic shows 11 volts in the battery then when i start the car it charges to 13.5 or so then goes to 12.3 12.5 within 60 seconds or less then the whine and hot alt starts up.
I had it checked by a shop he says its ok. I am using a deep cycle battery short term as my original is being used elsewhere.
The battery checks ok at home with tester but the shop wants me to do a load test on it he thinks this is why my alt is getting hot. I checked all the connections (good) even at the start solenoid (new within a month) the alt puts out 20 amps at idle when it is doing this.
I checked the power on the 3 wire connector at the alternator too. 9.7 volts on one red and 12 on the other.My deep cycle battery is a bit weak/old but it seems fine can a not 100% battery cause this? when i start the car the dic shows 11 volts in the battery then when i start the car it charges to 13.5 or so then goes to 12.3 12.5 within 60 seconds or less then the whine and hot alt starts up.
Racer
Joined: Apr 2006
Posts: 435
Likes: 0
Shoot it with a thermo gun.For whatever reason GM alternators can heat up really fast (over 300 degrees) when they start to fail.The odd thing is that it's not from the bearings seizing,more like the regulation system is zonked.
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Thread Starter
Pro
Joined: Oct 2006
Posts: 585
Likes: 57
From: Toronto
with koeo the bat guage shoes 11 volts when the engine running it goes 13.5 then down as it heats up i shot the alternator with my thermal image gun and it showed over 150 degrees and 197 on the centre portion and inside the fins on the case i also just spun it up with my drill on a vice and it didnt even get warm by one degree
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
with koeo the bat guage shoes 11 volts when the engine running it goes 13.5 then down as it heats up i shot the alternator with my thermal image gun and it showed over 150 degrees and 197 on the centre portion and inside the fins on the case i also just spun it up with my drill on a vice and it didnt even get warm by one degree
Have you thoroughly checked the other end of that B+ cable on the alternator? It runs directly to the starter solenoid, and MUST be securely fastened.
Cruising
Joined: Sep 2021
Posts: 12
Likes: 2
Same issues
with koeo the bat guage shoes 11 volts when the engine running it goes 13.5 then down as it heats up i shot the alternator with my thermal image gun and it showed over 150 degrees and 197 on the centre portion and inside the fins on the case i also just spun it up with my drill on a vice and it didnt even get warm by one degree
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
