Correct Coolant Temp
Thread Starter
Instructor
Joined: Oct 2007
Posts: 201
Likes: 1
From: NY
Correct Coolant Temp
Drove my 2004 Vert 150 miles on the highway with the coolant temp steady at about 190. Once on the street the temp hung around at 200 but when i was stopped at a light it would climb rapidly to about 230. As the light changed and the car got back in motion the temp dropped back to about 200. The air conditioner was off the whole time. Took it to my local garage and the plugged it into the computer and it showed no codes, both fans were running. We did notice the driver side fan ran on low while the passenger side was running on high. How hot is too hot?
Tech Contributor
Joined: May 2008
Posts: 3,100
Likes: 17
From: Somers, CT and Clermont, FL
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16
Sounds like you have a bad fan. Electrically it's impossible for the two fans to vary in speed by more than a small amount unless one of the fans is bad or restricted by debris such as a plastic bag wrapped around the blades or fan shaft. GM achieves low speed by putting the fans in series so about half of 12 volts is across each fan motor so that the fans cannot reach rated speed. Throught a series of fuses and relays they switch the motors to parallel arrangement so that 12 volts is across each fan motor thereby allowing the fans to reach rated RPM's.
Exactly right!
Burning Brakes
Joined: Sep 2010
Posts: 1,137
Likes: 4
From: Indianapolis Indiana
St. Jude Donor '13, '15, ‘18, '21
When should the fans kick on and off? Had my Z at the tuner and originally thought the fans were not coming on the car was sitting at 220*. The fans come on with the AC being turned on.
Burning Brakes
Joined: Sep 2010
Posts: 1,137
Likes: 4
From: Indianapolis Indiana
St. Jude Donor '13, '15, ‘18, '21
Thanks for all the info...I will verify the fans are low and high at the set temps. Sounds like they run hot when just sitting around and not at cruising speed.
Tech Contributor
Joined: Oct 1999
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From: Charlotte, NC (formerly Endicott, NY)
Bill
Thread Starter
Instructor
Joined: Oct 2007
Posts: 201
Likes: 1
From: NY
Does this apply to the LS1 as well as the Z?
Factory turn on temps for the cooling fans when the AC is OFF are as follows:
When the coolant temp exceeds 225 degrees the fans come on in low speed mode. When the coolant drops to 219 degrees the fans are commanded off. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. If the coolant temp drops to 226 degrees then the fans revert to low speed mode. BOTH fans run in low speed mode and BOTH fans run in high speed mode.
If the AC is ON then the fans come on in low speed mode at 185 degrees. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. They revert to low speed mode when the coolant temp drops to 226 degrees.
If the vehicle speed exceeds 35 mph then the fans are commanded OFF irrespective of the coolant temp or whether the AC is running or not. GM apparently felt that the fans free wheeling at above 35 MPH provided better air flow through the radiator than operating the fans.
Fan turn on temps for low speed and for high speed can be set to other than factory settings. I run a 170 T'stat and my fans come on at 199 and 209 with AC OFF. If you set the turn on temps too low, the fans will run continuously and they will wear out more quickly since they were not designed to run in continuous mode. Keep that in mind if you readjust fan turn on temps.
When the coolant temp exceeds 225 degrees the fans come on in low speed mode. When the coolant drops to 219 degrees the fans are commanded off. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. If the coolant temp drops to 226 degrees then the fans revert to low speed mode. BOTH fans run in low speed mode and BOTH fans run in high speed mode.
If the AC is ON then the fans come on in low speed mode at 185 degrees. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. They revert to low speed mode when the coolant temp drops to 226 degrees.
If the vehicle speed exceeds 35 mph then the fans are commanded OFF irrespective of the coolant temp or whether the AC is running or not. GM apparently felt that the fans free wheeling at above 35 MPH provided better air flow through the radiator than operating the fans.
Fan turn on temps for low speed and for high speed can be set to other than factory settings. I run a 170 T'stat and my fans come on at 199 and 209 with AC OFF. If you set the turn on temps too low, the fans will run continuously and they will wear out more quickly since they were not designed to run in continuous mode. Keep that in mind if you readjust fan turn on temps.
Melting Slicks
Joined: Apr 2002
Posts: 2,631
Likes: 2
From: Clever, MO aka SOMO
Factory turn on temps for the cooling fans when the AC is OFF are as follows:
When the coolant temp exceeds 225 degrees the fans come on in low speed mode. When the coolant drops to 219 degrees the fans are commanded off. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. If the coolant temp drops to 226 degrees then the fans revert to low speed mode. BOTH fans run in low speed mode and BOTH fans run in high speed mode.
If the AC is ON then the fans come on in low speed mode at 185 degrees. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. They revert to low speed mode when the coolant temp drops to 226 degrees.
If the vehicle speed exceeds 35 mph then the fans are commanded OFF irrespective of the coolant temp or whether the AC is running or not. GM apparently felt that the fans free wheeling at above 35 MPH provided better air flow through the radiator than operating the fans.
Fan turn on temps for low speed and for high speed can be set to other than factory settings. I run a 170 T'stat and my fans come on at 199 and 209 with AC OFF. If you set the turn on temps too low, the fans will run continuously and they will wear out more quickly since they were not designed to run in continuous mode. Keep that in mind if you readjust fan turn on temps.
When the coolant temp exceeds 225 degrees the fans come on in low speed mode. When the coolant drops to 219 degrees the fans are commanded off. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. If the coolant temp drops to 226 degrees then the fans revert to low speed mode. BOTH fans run in low speed mode and BOTH fans run in high speed mode.
If the AC is ON then the fans come on in low speed mode at 185 degrees. If the coolant temp exceed 235 degrees then the fans come on in high speed mode. They revert to low speed mode when the coolant temp drops to 226 degrees.
If the vehicle speed exceeds 35 mph then the fans are commanded OFF irrespective of the coolant temp or whether the AC is running or not. GM apparently felt that the fans free wheeling at above 35 MPH provided better air flow through the radiator than operating the fans.
Fan turn on temps for low speed and for high speed can be set to other than factory settings. I run a 170 T'stat and my fans come on at 199 and 209 with AC OFF. If you set the turn on temps too low, the fans will run continuously and they will wear out more quickly since they were not designed to run in continuous mode. Keep that in mind if you readjust fan turn on temps.
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Burning Brakes
Joined: Sep 2010
Posts: 1,137
Likes: 4
From: Indianapolis Indiana
St. Jude Donor '13, '15, ‘18, '21
Picked up the car yesterday. Since I ran across this thread I figured I would update with what I saw on my gauges. When on the hwy the car temps were running between 185 and 187. After I got off and was stuck in a moderate amount of traffic they climbed steadily up to 235 or so. Once I would start up in traffic they would again drop back into the 227 range and fall off a bit more if I was able to drive further then just up to the next light. The oil temp was (I think if I recall correctly) 190 sitting at idle in my driveway. To see how it did I let it sit in the driveway while I unloaded a few things and loaded up a few others. The temp climbed again then dropped to 227ish then down to 221, it bounced around a bit then after a little while it held pretty steady right at 221 while sitting at idle.
Just an FYI, I will watch my oil temps a bit and see what they do for my own knowledge.
Just an FYI, I will watch my oil temps a bit and see what they do for my own knowledge.
Thread Starter
Instructor
Joined: Oct 2007
Posts: 201
Likes: 1
From: NY
Picked up the car yesterday. Since I ran across this thread I figured I would update with what I saw on my gauges. When on the hwy the car temps were running between 185 and 187. After I got off and was stuck in a moderate amount of traffic they climbed steadily up to 235 or so. Once I would start up in traffic they would again drop back into the 227 range and fall off a bit more if I was able to drive further then just up to the next light. The oil temp was (I think if I recall correctly) 190 sitting at idle in my driveway. To see how it did I let it sit in the driveway while I unloaded a few things and loaded up a few others. The temp climbed again then dropped to 227ish then down to 221, it bounced around a bit then after a little while it held pretty steady right at 221 while sitting at idle.
Just an FYI, I will watch my oil temps a bit and see what they do for my own knowledge.
Just an FYI, I will watch my oil temps a bit and see what they do for my own knowledge.