Possible mod to the "Fan switch Mod" - Cherokee SRT8 Forum
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post #1 of 6 (permalink) Old 05-10-2007, 04:46 PM Thread Starter
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Possible mod to the "Fan switch Mod"

I haven't even changed the thermostat yet, so I don't know if this is a good idea or not. But, as I understand the situation, even after changing to a lower temp thermostat, it is still necessary to install a manual fan switch to cause the high speed fan to run so that you can take advantage of the lower temp thermostat. Here's the problem that I can see with a manual fan switch...it could be running more than needed. I know that shouldn't be a big problem but this idea might take care of that issue.
Why not install a separate water temp sending unit that is designed to send a voltage signal at a certain water temp? That signal could then be routed to a relay that would start the fans. A manual "On/Off" switch could still be incorporated into the design that would energize the whole system but the actual triggering at temp would be accomplished by the sending unit.
What do you think....Good or Bad idea.
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post #2 of 6 (permalink) Old 05-10-2007, 06:13 PM
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Good idea.

The problems we see with this idea were,where will you add the separate sending unit? Drill a new hole in the radiator? Most guys want it as simple as possible. I believe the B&G kicks the fans on a bit earlier, could be wrong on that. And why not just change the current one to a lower reading switch.

If you use this manual switch correctly you will have no problems. At the track, at a light, or before a race. Other wise you wouldn't want it to run all the time anyway.

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post #3 of 6 (permalink) Old 05-10-2007, 07:39 PM
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It has been done before using a mechanical reostat with the temperature probe inserted into the radiator fins. There are some other steps as well, there is a good write-up on the LX-forums, search for fan mods. GC

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post #4 of 6 (permalink) Old 05-10-2007, 07:57 PM
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What happens when the AC comes on? The fan should run all the time to keep the condenser cool. I really don't think the thermostat is the answer. I really think a cold induction scoop on the hood along with a lower fan temp setting is the trick.


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post #5 of 6 (permalink) Old 05-11-2007, 11:46 AM
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It's nice to keep this simple. Sure there are always diff ways to do things but using the ground side is the safest.
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post #6 of 6 (permalink) Old 05-12-2007, 06:23 PM
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Don't know if this is the safest approach, but have run the low speed fan bypass mod along with a lower temp thermostat (180 degree Motorad thermostat) for the past 9 months. With the Dashhawk monitoring, it's clear that its not only the coolant temps and oil temps that benefit, but the transmission fluid temps stay in the high 160's to low 170's range as well. Given the wear and tear issues that engine/transmission fluids have at high temps, the low speed fan bypass along with a lower temp thermostat makes a lot of sense to me.
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