Programming changes?
Thread Starter
Instructor
Joined: Aug 2025
Posts: 101
Likes: 84
From: Troy, MO
Programming changes?
Fairly new C5 owner with a 2002 6-speed convertible. I would like to lower the temperature the fans come on and have read this can be done by a tuner. I am going to see if I can find someone local to me that can make this change. My question is if there are any other programming changes that are recommended while I am having this done? Car is bone stock right now. Just wanted any suggestions so I can get things done all at once if there are other recommended changes that will help. Thank you!
Tech Contributor
Joined: Jan 2007
Posts: 19,511
Likes: 1,186
From: Dyer, IN
Fairly new C5 owner with a 2002 6-speed convertible. I would like to lower the temperature the fans come on and have read this can be done by a tuner. I am going to see if I can find someone local to me that can make this change. My question is if there are any other programming changes that are recommended while I am having this done? Car is bone stock right now. Just wanted any suggestions so I can get things done all at once if there are other recommended changes that will help. Thank you!
Melting Slicks
Joined: Sep 2021
Posts: 2,555
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Since you mentioned that you are a fairly new C5 owner I'll point out that a properly functioning cooling system does not benefit from such a change. If you're regularly seeing 240+ temps it's worth investigating to find the source of the issue, which is typically a partially clogged radiator that has sucked debris over the years and is now partially blocked. Can get under the car and pull some of it out and possibly blow some more out if you have access to an air compressor and a very small blower nozzle that will fit down near the A/C condenser and radiator once you remove a couple screws to gain access.
You should be able to idle around town in stop and go traffic with no overheating issues if your system is working properly.
You should be able to idle around town in stop and go traffic with no overheating issues if your system is working properly.
Thread Starter
Instructor
Joined: Aug 2025
Posts: 101
Likes: 84
From: Troy, MO
Thank you for the information. I cleaned the radiator and condenser and it all seems to be functioning correctly. In stop and go traffic it will get to 220 or so. If this is normal, than I should be ok. I guess I am just used to old school vehicles that never get above 190 or so.
Tech Contributor
Joined: Jan 2007
Posts: 19,511
Likes: 1,186
From: Dyer, IN
Thank you for the information. I cleaned the radiator and condenser and it all seems to be functioning correctly. In stop and go traffic it will get to 220 or so. If this is normal, than I should be ok. I guess I am just used to old school vehicles that never get above 190 or so.
As previously mentioned, it is good practice to confirm you do not have debris clogging the condenser and radiator, fans are turning on at factory setpoints for low and high speed, and the system is properly service.
Melting Slicks
Joined: Sep 2021
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I have a stock system as far as I know and I see 230 now and then on the hottest days around town in central Texas. 220 is pretty routine around town. Highway speeds are in the 190ish range.
As lucky showed in the tech document the PCM doesn't even set an over temp warning until 256.
If you really want the fans to run at 185 you can turn on the A/C.
As lucky showed in the tech document the PCM doesn't even set an over temp warning until 256.
If you really want the fans to run at 185 you can turn on the A/C.
Tech Contributor
Joined: Jan 2007
Posts: 19,511
Likes: 1,186
From: Dyer, IN
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Safety Car
Joined: Jan 2012
Posts: 3,956
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From: Da U.P.
All you guys telling OP to not lower his fan temps are full of it. There is no need to let the engine heat soak that far, it certainly won't hit 220 going down the highway. If you want sky high IATs and a gutted timing map then keep it stock by all means.
Melting Slicks
Joined: Sep 2021
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Too bad the GM engineers didn't consult the internet before they designed the car.
Tech Contributor
Joined: Jan 2007
Posts: 19,511
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From: Dyer, IN
Probably better giving advice for those trying to squeeze an extra 7hp out of their motor just to go around in circles.
Safety Car
Joined: Jan 2012
Posts: 3,956
Likes: 520
From: Da U.P.
Christ...get serious. Engines have been running at these temperatuers for 20+ years....and news flash.....it's a stock street car. The OP is just not used to the newer tech. Sky high IATs?.....gutted timing map? Give me a break. Probably better giving advice for those trying to squeeze an extra 7hp out of their motor just to go around in circles.
Probably better giving advice for those trying to squeeze an extra 7hp out of their motor just to go around in circles.OP lower your fan temps and don't look back. In for a penny, in for a pound so see if your local tuner can't find a little something something in there while he's at it. Just don't expect much, these weren't neutered the way the trucks were of the era.
Tech Contributor
Joined: Jan 2007
Posts: 19,511
Likes: 1,186
From: Dyer, IN
The concept of the end user having different goals than the engineers who are beholden to the EPA, beancounters, NVH, etc is truly lost on you guys. Better not touch the exhaust or engine internals either because GM didn't deliver it that way and after all they know best.
OP lower your fan temps and don't look back. In for a penny, in for a pound so see if your local tuner can't find a little something something in there while he's at it. Just don't expect much, these weren't neutered the way the trucks were of the era.
OP lower your fan temps and don't look back. In for a penny, in for a pound so see if your local tuner can't find a little something something in there while he's at it. Just don't expect much, these weren't neutered the way the trucks were of the era.
Drifting
Joined: Nov 2017
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Melting Slicks
Joined: Feb 2001
Posts: 2,805
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From: Northville, MI
Our local club was fortunate to have about 40 engineers/programmers when the C5 corvette was starting development--about 1991. The best computer at that time was the PS2 (286) and it ran thru the entine C5 production. The PCM was developed by trial and error to meet the EPA requirements for that time and the higher engine temps were very important to meet those standards. The 97-99 easily met them while the 2000 had to be detuned to meet them. The 2001-2004 had a different cam and intake which made it easier to calibrate. When the engineers went autocrossing and racing besides retuning the engine they also lowered the operating temps. however they looked at the OIL TEMP as the defining factor, Around 2008 the aftermarket programmers were able to map the entire 96K of programmable engine data and soon many went to the lowered starting temps for the fans. Today if you live in a smog regulated state it is best to keep the original temps to pass emission test, otherwise lowering the temps for the fans to tun on is OK. One of the leading causes for high engine and oil temps is the center air deflector bent backwards, Going down the street is fine but stopped in traffic the temps rise to higher than 235F
Thread Starter
Instructor
Joined: Aug 2025
Posts: 101
Likes: 84
From: Troy, MO
Great information Gordy. Thank you. This is my first C5 and LS. I will probably wait and see how the car performs next summer when it starts getting hot outside and then make my decision on whether to lower or not.