Newest ways of avoiding excessive heat on the LT1's
03-26-2019, 07:52 AM
#1
Newest ways of avoiding excessive heat on the LT1's
Hi guys, first time poster here.
I just inherited a 1994 LT1 that my dad owned for a very long time. It's been taken good care of but I do know that it runs hot but my dad never took much action against it because he knew that the system was inherently designed to run that way. Me; it makes me a little worried. It'll run hot in stop and go traffic, it'll be fine when it's moving and getting air, or it'll pretty much always be fine if the A/C is on and the fans are running. I'm looking for ways to either get the fans to come on at earlier temperatures or I suppose adding in a manual fan switch would work. I'd be lying if I said that I wouldn't prefer the former.
Anyway, I've done a bit of researching and one thing I found was Corvettemods.com's Low Temperature Cooling Fan Kit which seems like it would potentially work, however when I researched it a little bit more (quite a few of the threads were on this forum, actually), I saw a lot of people stating that a kit like that would be a lot less useful without a ECM re-program. Those same people recommended seeing certain vendors or names but the problem is that all of those posts are from more than a decade ago. I haven't tried contacting anyone (yet) but I'm not even sure if those people are still in the business.
Point is: my LT1 runs hot like all LT1's do. I don't like it and I'd like for the cooling fans to come on a bit quicker. As of 2019, what's the best/easiest way to achieve this? Will the kit that I linked above work or will I also need to find someone to re-program the ECM?
I just inherited a 1994 LT1 that my dad owned for a very long time. It's been taken good care of but I do know that it runs hot but my dad never took much action against it because he knew that the system was inherently designed to run that way. Me; it makes me a little worried. It'll run hot in stop and go traffic, it'll be fine when it's moving and getting air, or it'll pretty much always be fine if the A/C is on and the fans are running. I'm looking for ways to either get the fans to come on at earlier temperatures or I suppose adding in a manual fan switch would work. I'd be lying if I said that I wouldn't prefer the former.
Anyway, I've done a bit of researching and one thing I found was Corvettemods.com's Low Temperature Cooling Fan Kit which seems like it would potentially work, however when I researched it a little bit more (quite a few of the threads were on this forum, actually), I saw a lot of people stating that a kit like that would be a lot less useful without a ECM re-program. Those same people recommended seeing certain vendors or names but the problem is that all of those posts are from more than a decade ago. I haven't tried contacting anyone (yet) but I'm not even sure if those people are still in the business.
Point is: my LT1 runs hot like all LT1's do. I don't like it and I'd like for the cooling fans to come on a bit quicker. As of 2019, what's the best/easiest way to achieve this? Will the kit that I linked above work or will I also need to find someone to re-program the ECM?
03-26-2019, 09:23 AM
#2
Don't have much to say on the kit, but avoid corvettemods. They are the worst when it comes to customer service. Do a search on the forum.
03-26-2019, 09:29 AM
#4
Team Owner
Pro Mechanic
100%.You're looking to treat a psychological problem....not an actual one.
.
Last edited by Tom400CFI; 03-26-2019 at 09:55 AM.
03-26-2019, 09:44 AM
#5
that kit you referenced goes up to '91, you have a '94.
Cheapest way I found was this, https://www.rockauto.com/en/moreinfo...041398&jsn=446
Installed in my '96, works fine, don't even have to open up the cooling system.
Cheapest way I found was this, https://www.rockauto.com/en/moreinfo...041398&jsn=446
Installed in my '96, works fine, don't even have to open up the cooling system.
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GRKLGHTNG (04-12-2019)
03-26-2019, 10:15 AM
#7
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It is by design the car runs warmer, but if the fans are staying on there are some things you can do to help.
1. Make sure t-stat is working. It opens at 180F. If you see the digital gauge pause here for some time in the morning, its working. If it skyrockets beyond, it may be sticking. Don't trust analog gauge.
2. Make sure space between radiator and condensor is clear, it fills up with leaves and blocks airflow. You wouldn't think it would suck up that much but it can.
3. Verify fans are working, main should come on around 228F. If there is a pusher in front, it'll come about 10F higher.
4. Check that WP is not weeping.
5. If coolant has never been changed, change it all out. You should do it every few years anyway.
If you still feel uncomfortable after that, it does require PCM reflash to change the fan settings. You should not need a lower temp stat, 180 is fine. Upgrading the radiator to a thicker unit like DeWitt will solve any overheating issue that isn't coming from something internal to the motor like blocked passages, but normal coolant temps for the engine in traffic will be around the factory fan temps. Once youre moving the temps should be in the 200-215 (oil) and 180-190 (coolant) range.
1. Make sure t-stat is working. It opens at 180F. If you see the digital gauge pause here for some time in the morning, its working. If it skyrockets beyond, it may be sticking. Don't trust analog gauge.
2. Make sure space between radiator and condensor is clear, it fills up with leaves and blocks airflow. You wouldn't think it would suck up that much but it can.
3. Verify fans are working, main should come on around 228F. If there is a pusher in front, it'll come about 10F higher.
4. Check that WP is not weeping.
5. If coolant has never been changed, change it all out. You should do it every few years anyway.
If you still feel uncomfortable after that, it does require PCM reflash to change the fan settings. You should not need a lower temp stat, 180 is fine. Upgrading the radiator to a thicker unit like DeWitt will solve any overheating issue that isn't coming from something internal to the motor like blocked passages, but normal coolant temps for the engine in traffic will be around the factory fan temps. Once youre moving the temps should be in the 200-215 (oil) and 180-190 (coolant) range.
03-26-2019, 10:18 AM
#8
The space between the radiator and condenser is clear. I'm already well aware that leaves and crap like to accumulate.
And I know that the LT1's run hot, but it still makes me paranoid. The last time it was inspected (which was a few years ago as NJ no longer requires inspection on cars that old), while sitting in line at the DMV on a 90F day, temperatures were a hair below the max line...like I said, temps seem to stay fine with the A/C and fans on. But if that's truly how things are designed, maybe I'll just learn to ignore it.
And I know that the LT1's run hot, but it still makes me paranoid. The last time it was inspected (which was a few years ago as NJ no longer requires inspection on cars that old), while sitting in line at the DMV on a 90F day, temperatures were a hair below the max line...like I said, temps seem to stay fine with the A/C and fans on. But if that's truly how things are designed, maybe I'll just learn to ignore it.
03-26-2019, 11:01 AM
#9
Team Owner
Pro Mechanic
The analog gauge will go to, or very near to "the max line" right before the fans come on. It's dumb, totally inaccurate/misleading...and almost worthless. THink of the analog gauge as a "cold/warm/HOT" indicator...not as an actual gauge. If you want real information, scroll to engine temp in the DIC and observe the digital display. 
You're right; the gauge is disconcerting. Once you realize that it's virtually worthless, it becomes a lot less "stressful".
You're right; the gauge is disconcerting. Once you realize that it's virtually worthless, it becomes a lot less "stressful".
03-26-2019, 11:09 AM
#10
Got it. While the car has come out of hibernation, we're still seeing ~40F weather here in Jersey so I don't expect temps to be a problem for another couple of months but I'll keep that in mind. I'll start monitoring the electronic readout instead of the analog gauge. What's the "normal" temperature that I should be seeing on a hot day? Is 220-240 normal for sitting in stop and go traffic during a 90F day? I have seen those types of temps in those circumstances but that was also bright, Sunny, and with the targa top off so the A/C was off as well. Maybe it'd be better just to keep the A/C and fans on even with the roof off....
03-26-2019, 12:18 PM
#11
Le Mans Master
Got it. While the car has come out of hibernation, we're still seeing ~40F weather here in Jersey so I don't expect temps to be a problem for another couple of months but I'll keep that in mind. I'll start monitoring the electronic readout instead of the analog gauge. What's the "normal" temperature that I should be seeing on a hot day? Is 220-240 normal for sitting in stop and go traffic during a 90F day? I have seen those types of temps in those circumstances but that was also bright, Sunny, and with the targa top off so the A/C was off as well. Maybe it'd be better just to keep the A/C and fans on even with the roof off....
03-26-2019, 12:35 PM
#12
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240 (coolant) would be somewhat worrisome, 250 is the danger zone, 260 you better pull over and cut it off.
03-26-2019, 12:50 PM
#13
Team Owner
Pro Mechanic
It's my opinion that the fan should draw down the temps pretty fast, when "sitting in stop and go traffic". Bottom line? If MY temps went above 235 sitting in traffic, I'd be doing some cooling system maintenance. If I'm running my AC in traffic (which forces the fan on), then I don't expect it to ever go above 210.
03-26-2019, 01:09 PM
#15
Race Director
Hi guys, first time poster here.
I just inherited a 1994 LT1 that my dad owned for a very long time. It's been taken good care of but I do know that it runs hot but my dad never took much action against it because he knew that the system was inherently designed to run that way. Me; it makes me a little worried. It'll run hot in stop and go traffic, it'll be fine when it's moving and getting air, or it'll pretty much always be fine if the A/C is on and the fans are running. I'm looking for ways to either get the fans to come on at earlier temperatures or I suppose adding in a manual fan switch would work. I'd be lying if I said that I wouldn't prefer the former.
Anyway, I've done a bit of researching and one thing I found was Corvettemods.com's Low Temperature Cooling Fan Kit which seems like it would potentially work, however when I researched it a little bit more (quite a few of the threads were on this forum, actually), I saw a lot of people stating that a kit like that would be a lot less useful without a ECM re-program. Those same people recommended seeing certain vendors or names but the problem is that all of those posts are from more than a decade ago. I haven't tried contacting anyone (yet) but I'm not even sure if those people are still in the business.
Point is: my LT1 runs hot like all LT1's do. I don't like it and I'd like for the cooling fans to come on a bit quicker. As of 2019, what's the best/easiest way to achieve this? Will the kit that I linked above work or will I also need to find someone to re-program the ECM?
I just inherited a 1994 LT1 that my dad owned for a very long time. It's been taken good care of but I do know that it runs hot but my dad never took much action against it because he knew that the system was inherently designed to run that way. Me; it makes me a little worried. It'll run hot in stop and go traffic, it'll be fine when it's moving and getting air, or it'll pretty much always be fine if the A/C is on and the fans are running. I'm looking for ways to either get the fans to come on at earlier temperatures or I suppose adding in a manual fan switch would work. I'd be lying if I said that I wouldn't prefer the former.
Anyway, I've done a bit of researching and one thing I found was Corvettemods.com's Low Temperature Cooling Fan Kit which seems like it would potentially work, however when I researched it a little bit more (quite a few of the threads were on this forum, actually), I saw a lot of people stating that a kit like that would be a lot less useful without a ECM re-program. Those same people recommended seeing certain vendors or names but the problem is that all of those posts are from more than a decade ago. I haven't tried contacting anyone (yet) but I'm not even sure if those people are still in the business.
Point is: my LT1 runs hot like all LT1's do. I don't like it and I'd like for the cooling fans to come on a bit quicker. As of 2019, what's the best/easiest way to achieve this? Will the kit that I linked above work or will I also need to find someone to re-program the ECM?
add 160 tstat. Theres strong opinions both ways on this.
All i can say is mine used to run 220F, now runs at 170F as a result of those 2 changes
May get more worse emissions - i believe thats why gm made them run hot. May create a stinkier
exhaust (esp if you dont have cats).
good luck
03-26-2019, 01:41 PM
#16
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I take it that you have read this through completely ..... and you are still concerned? No need to be concerned. BUT learn to use the digital temp readouts.
https://www.corvetteforum.com/forums...peratures.html
https://www.corvetteforum.com/forums...peratures.html
03-26-2019, 04:01 PM
#17
Instructor
I've had my '92 for 3-4 yrs now. It took a little time to get used to but you will. Don't worry about it. My analog gauge just about pegs before the fans come on. The digital gauge goes to 220 something before they come on. Driving down the road on a cool day without the AC on mine will range from 198-207. Never overheated. It's a great engine, drive it.
03-26-2019, 05:03 PM
#18
Melting Slicks
Honestly, I have never heard anyone having problems related to the factory cooling system design. The temps can get higher than most people are used to, but not by much. If modern cars had digital temp gauges, you'd see them in the 210-220F range on a regular basis, maybe higher. Having said that...
The best way to keep things cool is to check everything as stated in post #7 -- and if you flush the cooling system, you MUST pull the knock sensors. Then, when everything is in good working order and you notice the temps getting too high for your "comfort," just turn on the AC as stated in post #13. This forces the fans on and the temps will drop quickly. Mine drops at least 15 degrees in 2 minutes once the AC is turned on. I don't mind my LT1 getting up around 220-225F but I don't like it to stay there, so if there's no sign of traffic moving soon, I simply kick on the AC. But whenever it needs a smog check, of course it sits there idling for like 20 minutes while the tech does their thing. Ya it gets hot but never had a problem.
Installing a cooler thermostat on your factory system will not make it more efficient. It simply lowers the temperature at which the thermostat begins to open. Once it's open, it's open. The engine temperature really depends on the capacity of the cooling system, i.e. how much heat it can dissipate.
The best way to keep things cool is to check everything as stated in post #7 -- and if you flush the cooling system, you MUST pull the knock sensors. Then, when everything is in good working order and you notice the temps getting too high for your "comfort," just turn on the AC as stated in post #13. This forces the fans on and the temps will drop quickly. Mine drops at least 15 degrees in 2 minutes once the AC is turned on. I don't mind my LT1 getting up around 220-225F but I don't like it to stay there, so if there's no sign of traffic moving soon, I simply kick on the AC. But whenever it needs a smog check, of course it sits there idling for like 20 minutes while the tech does their thing. Ya it gets hot but never had a problem.
Installing a cooler thermostat on your factory system will not make it more efficient. It simply lowers the temperature at which the thermostat begins to open. Once it's open, it's open. The engine temperature really depends on the capacity of the cooling system, i.e. how much heat it can dissipate.
Last edited by DGXR; 03-26-2019 at 05:04 PM.
03-26-2019, 10:17 PM
#19
Installing a cooler thermostat on your factory system will not make it more efficient. It simply lowers the temperature at which the thermostat begins to open. Once it's open, it's open. The engine temperature really depends on the capacity of the cooling system, i.e. how much heat it can dissipate.
04-02-2019, 10:24 PM
#20
Melting Slicks
That is only part of the problem; get a dental pick and be prepared to spend a couple of hours picking a thousand bug pieces, grains of sand, and who knows what, that have lodged themselves into the cooling fins of the A/C condenser and radiator. This I know.