Running Hot at the stoplight
Thread Starter
Cruising
Joined: Feb 2014
Posts: 10
Likes: 0
From: Powder Springs Ga
Running Hot at the stoplight
I was in heavy traffic yasterday on the way home and noticed I was running hot. Turned on the heater full blast and took an alternate route home. Temp was OK as long as I keep moving. Got home and found out the fans are not coming on. Fans will work with the A/C on. Checked the fuses and swapped the relays out, but no fans. Need a sarting point to fix this problem. Thanks. 
Racer
Joined: Jun 2012
Posts: 419
Likes: 3
From: North Lauderdale FL
I was in heavy traffic yasterday on the way home and noticed I was running hot. Turned on the heater full blast and took an alternate route home. Temp was OK as long as I keep moving. Got home and found out the fans are not coming on. Fans will work with the A/C on. Checked the fuses and swapped the relays out, but no fans. Need a sarting point to fix this problem. Thanks.
Le Mans Master
Joined: Dec 2000
Posts: 5,245
Likes: 25
From: Blue Ridge Georgia
That is a sign that you are not getting air flow over the rad if you are stopped. That means that your rad or your AC condenser is dirty and won't let the air thru. Very common in the C5. You can use compressed air or a water hose nozzle to clean it out. Sometimes it takes some work to clear it up.
Team Owner
Joined: Jul 2006
Posts: 22,182
Likes: 4,178
From: Kannapolis NC
I guess they didn't notice the part about no fans working. If you get in that situation, don't turn on the heat, turn on the a/c to force the fans on to help with the cooling. At 226 degrees, both fans should come on. What temp did you run when stopped?
Thread Starter
Cruising
Joined: Feb 2014
Posts: 10
Likes: 0
From: Powder Springs Ga
It was over 220 and I had a reduced power message on the message center. It normally runs about 190-196. I don't know what thermostat is in the car. I guess I should look to find out.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
Here is how the fans should work:
Factory temp settings are low speed on at 226 degrees and off at 219 degrees. High speed on at 235 degrees and revert to low speed at 226 degrees. As stated both fans run at low speed and high speed and fans are commanded off by the PCM when the vehicle speed exceeds 35mph.
You can force low speed operation at 185 degrees by turning on the AC. High speed operation with AC on is still 235 degrees.
From 8VETTE7, Chuck
Factory temp settings are low speed on at 226 degrees and off at 219 degrees. High speed on at 235 degrees and revert to low speed at 226 degrees. As stated both fans run at low speed and high speed and fans are commanded off by the PCM when the vehicle speed exceeds 35mph.
You can force low speed operation at 185 degrees by turning on the AC. High speed operation with AC on is still 235 degrees.
From 8VETTE7, Chuck
Thread Starter
Cruising
Joined: Feb 2014
Posts: 10
Likes: 0
From: Powder Springs Ga
Here is how the fans should work:
Factory temp settings are low speed on at 226 degrees and off at 219 degrees. High speed on at 235 degrees and revert to low speed at 226 degrees. As stated both fans run at low speed and high speed and fans are commanded off by the PCM when the vehicle speed exceeds 35mph.
You can force low speed operation at 185 degrees by turning on the AC. High speed operation with AC on is still 235 degrees.
From 8VETTE7, Chuck
Factory temp settings are low speed on at 226 degrees and off at 219 degrees. High speed on at 235 degrees and revert to low speed at 226 degrees. As stated both fans run at low speed and high speed and fans are commanded off by the PCM when the vehicle speed exceeds 35mph.
You can force low speed operation at 185 degrees by turning on the AC. High speed operation with AC on is still 235 degrees.
From 8VETTE7, Chuck
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Race Director
Joined: May 2006
Posts: 10,912
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From: EAST TENNESSEE
That is a sign that you are not getting air flow over the rad if you are stopped. That means that your rad or your AC condenser is dirty and won't let the air thru. Very common in the C5. You can use compressed air or a water hose nozzle to clean it out. Sometimes it takes some work to clear it up.
I had the same problem,mine didn't look dirty,but both were full of bugs and dust. I used compressed air blowing from back towards front end. Fixed my over heating problems. Take your time,careful to not damage rad.fins.