overheating
03-28-2007, 11:46 PM
#32
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Location: Rochester Hills, MI
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03-28-2007, 11:50 PM
#33
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http://www.theherd.com/articles/lt1_cool.html
Additionally, the PCM will turn off the
fans at higher vehicle speeds (above 48 MPH I believe) since running fans can
actually impede airflow through the radiator at high speed. Each fan also has a
minimum running time.
fans at higher vehicle speeds (above 48 MPH I believe) since running fans can
actually impede airflow through the radiator at high speed. Each fan also has a
minimum running time.
03-29-2007, 12:27 AM
#34
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The fans turn off above a speed threshold, true, but in all designs I know, it's not because they reduce flow if on above that speed. MAYBE there could be a special case where it happens, but I've never seen it and it's certainly not common by design. I think you'd have to try pretty hard to get a system to do that, if you could at all. Unless you run the fans backwards, of course!
Based on my education and my experience with lots of data and testing on multiple systems:
The powered airflow increment (how much the fan helps) decreases with increased inlet velocity (above the 'stall speed' if applicable) but it does not go negative. In other words, the fans help less and less, approaching zero, the faster the car goes.
I didn't do the F-cars, but all the fan designs I have ever dealt with deliver higher flow at higher rpm for all design conditions, and always have higher RPM at higher voltages, even at high inlet pressures (high speeds). That is, they don't hurt flow when power is on at high speeds.
As a matter of fact, I studied several fan performance & system resistance curves today specifically for the purpose of evaluating the powered flow increment vs vehicle speed. It was not negative in any cases, even the ones that were not well matched for fan performance.
03-29-2007, 01:11 AM
#35
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when i changed my optispark i had the same problem because there was an air pocket in the engine somewhere which makes the temp gauge climb really fast i drove it on the freeway and then the check gauges light came on, i also had the same problem when i changed my water pump on a 92 tpi which was because of an air pocket in the engine. to fix the problem what you need to do is come across an HVAC tool which pressurizes the system with a fitting that hooks up to a compressor, then it fully fills the system back up from coolant that it syphones from a bucket. every time it has fixed the problem maybe that could be it for you. even if it looks like theres a sufficent amount of coolant there cold still be an airpocket hiding somewhere.
03-30-2007, 08:57 PM
#39
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No worries, I knocked on wood before I sent that last post. Before I sound like an *******, I do appreciate the help heatmaker. Diagnostics aren't that easy when you aren't there to actually see what the car is doing.
Last edited by RKPsk8er; 03-30-2007 at 08:59 PM.
03-31-2007, 01:10 PM
#40
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No, you don't understand what I mean. WHenever these cars... especially LT1's reach the red zone You never know exactly how much damage may have been done. They might be fine, or they might have a problem that you don't realize yet... but if you run an air damn, or no air dam, and the car goes past 210 and stays past 210 with both fans on and doesn't cool back down at all then there's something else that is an issue. Atleast in my case, I haven't ran an Air dam in the past 5 years. Just fans only, and the car stays below 195 always. These cars will over heat without the air dams yes, but not to the red zone, because the fans will prevent that. You need to figure out what's going on with your car.
With your car in park, and the A/C on, how high does the temperature climb?
With your car in park, and the A/C on, how high does the temperature climb?
Last edited by Heatmaker; 03-31-2007 at 01:15 PM.
03-31-2007, 01:56 PM
#41
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Location: Baton Rouge, LA
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No, you don't understand what I mean. WHenever these cars... especially LT1's reach the red zone You never know exactly how much damage may have been done. They might be fine, or they might have a problem that you don't realize yet... but if you run an air damn, or no air dam, and the car goes past 210 and stays past 210 with both fans on and doesn't cool back down at all then there's something else that is an issue. Atleast in my case, I haven't ran an Air dam in the past 5 years. Just fans only, and the car stays below 195 always. These cars will over heat without the air dams yes, but not to the red zone, because the fans will prevent that. You need to figure out what's going on with your car.
With your car in park, and the A/C on, how high does the temperature climb?
With your car in park, and the A/C on, how high does the temperature climb?
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