C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Fan Help

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Old Sep 15, 2004 | 01:55 AM
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Default Fan Help

I've got two things...first is that I don't think my fan is coming on at all unless I have the air conditioner running. I have gotten out of my car and opened the hood when my temp reads over 200 and i can't tell that either of the fans are on. Any ideas on how to fix this? Also in the same idea, how do i rewire (or reprogram) the fans to turn on at lower temperatures?
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Old Sep 15, 2004 | 08:50 AM
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You will have to get it hotter than that if you want to see the fans run, around 228. A custom chip can lower fan start temp or you can buy a lower aux fan switch and tie it into relays.
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Old Sep 15, 2004 | 09:24 AM
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Check out the tech section - there is a tech on installing a simple switch to turn the fan's on manually.
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Old Sep 15, 2004 | 01:28 PM
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Yep, agent86 is correct, fans are not coming on at 200 without help from a manual switch or a custom chip.

Here's a tech tip that I wrote that is mainly on testing the relays but also touches on wiring a manual fan switch and should help you understand the fans/relays a bit better.
https://www.corvetteforum.com/techti...=282&TopicID=2
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Old Sep 15, 2004 | 01:54 PM
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For your year, fans are controlled by the a/c pressure switch - they should both be on if the a/c is on; or the engine coolant temp switch signal to the PCM. That will turn the primary fan on at 219 - off at 208; and the secondary fan on at 228 - off at 217. These temps won't hurt your engine. If you're operating outside of these parameters, best to use a scanner first so that you can compare the gage reading with ECT signal. Otherwise, there is a basic cooling system problem - restricted air flow, plugged coolant passages, etc.
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Old Sep 15, 2004 | 02:19 PM
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The General designed our L98s to run in the 200-230 deg F range to meet emission stds. So the T-stat works around 195-200deg F and fans come on later.

If you want to lower engine temps, install a 180 deg or 160 deg T-stat and complimentary fan switch.

If you want to test your fan operation, simply open the connector to the A/C pressure switch or jumper ALDL pins A&B (upper right) and start the engine. At least the main fan should come on.
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Old Sep 15, 2004 | 03:53 PM
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to test them i know people mess with the fan switch relays to see if they even come on at all. my fan doesnt kick in until about 235 degrees, you think you got problems.
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Old Sep 16, 2004 | 05:51 AM
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LoL. I had the same problem with my 84. Fan took a crap. (So i thought)
you know its not the fans cuase they turn on when ac is on. do what 85vette said. get a manual fan switch. there easy. if i remember right. It's( switch-pos battery)(switch-cooling fan).you probably already know this but im trying to help. lol.

P.S.-the real problem about a manuall fan is REMEMBERING TO TURN IT OFF!!!!! Its grounds for a dead battery.lol.

zach-
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Originally Posted by 65Z01

The General designed our L98s to run in the 200-230 deg F range to meet emission stds. So the T-stat works around 195-200deg F and fans come on later.
Does this mean that if I go with a 160-180deg TStat, or basically do anything to lower my engine temps, I might have a problem with smogging it ?

I'm still getting used to how hot these engines were designed to run at.
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