cooling fan issue. Question.
Thread Starter
Race Director
Joined: Oct 2004
Posts: 13,587
Likes: 1,352
From: Home of the VOLS ! Knoxville, TN. Tennessee
St. Jude Donor '11-'12-'13, '15, '16-'17-'18-'19
cooling fan issue. Question.
2010 Base stock.
Verified that my cooling fan is overdrawing my voltage then shutting off.
Replacement units aren't that expensive, but the module is. Would you replace both?
Not sure what's causing the overdraw, but the OEM module is like $300. My guess is the bearings in the fan, but I don't want to do the R&R twice.
I don't want to replace it if I don't need it.
Thoughts?
Verified that my cooling fan is overdrawing my voltage then shutting off.
Replacement units aren't that expensive, but the module is. Would you replace both?
Not sure what's causing the overdraw, but the OEM module is like $300. My guess is the bearings in the fan, but I don't want to do the R&R twice.
I don't want to replace it if I don't need it.
Thoughts?
Drifting
Joined: Apr 2020
Posts: 1,754
Likes: 660
2010 Base stock.
Verified that my cooling fan is overdrawing my voltage then shutting off.
Replacement units aren't that expensive, but the module is. Would you replace both?
Not sure what's causing the overdraw, but the OEM module is like $300. My guess is the bearings in the fan, but I don't want to do the R&R twice.
I don't want to replace it if I don't need it.
Thoughts?
Verified that my cooling fan is overdrawing my voltage then shutting off.
Replacement units aren't that expensive, but the module is. Would you replace both?
Not sure what's causing the overdraw, but the OEM module is like $300. My guess is the bearings in the fan, but I don't want to do the R&R twice.
I don't want to replace it if I don't need it.
Thoughts?
I have an OEM fan off a 2013 GS with only 10k miles on the fan. Too bad you are not closer to the west coast.
Thread Starter
Race Director
Joined: Oct 2004
Posts: 13,587
Likes: 1,352
From: Home of the VOLS ! Knoxville, TN. Tennessee
St. Jude Donor '11-'12-'13, '15, '16-'17-'18-'19
The issue turned out to be not with the fan, but the brand new Mechman 170A alternator I just installed and that everyone was raving about. It failed in one day.
I just returned it and re-installed my AC Delco for now that was having a minor flicker. No overdraw any more. I was blaming the fan but the overdraw ended up being the alternator itself. Bummer.
I am just going to go back with a new AC Delco after I get my $525 back. AC Delco is only $435.
Last edited by corvettezman; May 22, 2026 at 06:14 PM.
Le Mans Master
Joined: Jun 2015
Posts: 6,328
Likes: 1,107
From: Austin Tx
Thanks!
The issue turned out to be not with the fan, but the brand new Mechman 170A alternator I just installed and that everyone was raving about. It failed in one day.
I just returned it and re-installed my AC Delco for now that was having a minor flicker. No overdraw any more. I was blaming the fan but the overdraw ended up being the alternator itself. Bummer.
I am just going to go back with a new AC Delco after I get my $525 back. AC Delco is only $435.
The issue turned out to be not with the fan, but the brand new Mechman 170A alternator I just installed and that everyone was raving about. It failed in one day.
I just returned it and re-installed my AC Delco for now that was having a minor flicker. No overdraw any more. I was blaming the fan but the overdraw ended up being the alternator itself. Bummer.
I am just going to go back with a new AC Delco after I get my $525 back. AC Delco is only $435.
Drifting
Joined: Apr 2020
Posts: 1,754
Likes: 660
Thanks!
The issue turned out to be not with the fan, but the brand new Mechman 170A alternator I just installed and that everyone was raving about. It failed in one day.
I just returned it and re-installed my AC Delco for now that was having a minor flicker. No overdraw any more. I was blaming the fan but the overdraw ended up being the alternator itself. Bummer.
I am just going to go back with a new AC Delco after I get my $525 back. AC Delco is only $435.
The issue turned out to be not with the fan, but the brand new Mechman 170A alternator I just installed and that everyone was raving about. It failed in one day.
I just returned it and re-installed my AC Delco for now that was having a minor flicker. No overdraw any more. I was blaming the fan but the overdraw ended up being the alternator itself. Bummer.
I am just going to go back with a new AC Delco after I get my $525 back. AC Delco is only $435.
Thread Starter
Race Director
Joined: Oct 2004
Posts: 13,587
Likes: 1,352
From: Home of the VOLS ! Knoxville, TN. Tennessee
St. Jude Donor '11-'12-'13, '15, '16-'17-'18-'19
I did not know that, so I ordered it on Ebay from a NY alternator distributor. after a 3 week wait, they drop shipped it from Mechman in Knoxville to me in Knoxville via FedEx and I received it the same day.
When I started the return with Ebay, they had me ship it back to NY instead. I could have hand delivered it to the Mechman's shop in Knoxville.
Drifting
Joined: Apr 2020
Posts: 1,754
Likes: 660
The funny part is that they are made here in Knoxville TN, about 3 miles away from my house.
I did not know that, so I ordered it on Ebay from a NY alternator distributor. after a 3 week wait, they drop shipped it from Mechman in Knoxville to me in Knoxville via FedEx and I received it the same day.
When I started the return with Ebay, they had me ship it back to NY instead. I could have hand delivered it to the Mechman's shop in Knoxville.
I did not know that, so I ordered it on Ebay from a NY alternator distributor. after a 3 week wait, they drop shipped it from Mechman in Knoxville to me in Knoxville via FedEx and I received it the same day.
When I started the return with Ebay, they had me ship it back to NY instead. I could have hand delivered it to the Mechman's shop in Knoxville.
Safety Car
Joined: Aug 2017
Posts: 4,922
Likes: 2,334
From: Etobicoke (Toronto) Ontario
So, you say the original alternator had a minor flicker? What does that mean? Did you have the root cause diagnosed and the verdict was the alternator? Otherwise, you guessed at the cause, threw an expensive part at it, and that didn’t fix it. Maybe there’s nothing wrong with Mechman. Could be a weak ground to the alternator frame, problem with the ECU, even excessive EMI interfering with the duty cycle signal. It’s not the good old days where the alternator had no external controls. Now, it’s the ECU that sends a PWM signal to the alternator that determines output.
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Thread Starter
Race Director
Joined: Oct 2004
Posts: 13,587
Likes: 1,352
From: Home of the VOLS ! Knoxville, TN. Tennessee
St. Jude Donor '11-'12-'13, '15, '16-'17-'18-'19
So, you say the original alternator had a minor flicker? What does that mean? Did you have the root cause diagnosed and the verdict was the alternator? Otherwise, you guessed at the cause, threw an expensive part at it, and that didn’t fix it. Maybe there’s nothing wrong with Mechman. Could be a weak ground to the alternator frame, problem with the ECU, even excessive EMI interfering with the duty cycle signal. It’s not the good old days where the alternator had no external controls. Now, it’s the ECU that sends a PWM signal to the alternator that determines output.
I have decided to take it in to the dealer for a diagnostic.
What I know though is my old alternator would run perfect until the car is fully warmed up, then the voltage would drop from 14V to 13V or less and the flicker starts, only at idle. Pick up the RPM to 1k plus and the flicker goes away.
The Mechman alternator would start alternating between 12V and 14V every few seconds right out of the gate. Like it did not know where to stay right off the bat. My Delco alternator does not do that. There are no sudden drops in voltage every few seconds like the Mechman was doing.
What is interesting also, is that while the Mechman was doing its crazy up and down variations, there was never a flicker, the lighting would dim a little until the voltage picks back up but no flicker. It did that approximately every five seconds.
Last edited by corvettezman; Yesterday at 02:38 AM.