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Unread 07-07-2013, 08:40 PM   #1
airwolf9090
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1996 ZJ 
 
Join Date: May 2011
Location: Clyo, Ga
Posts: 570
Overheating while siting still

Could my water pump be about shot? Its been like this for 2 years, I replaced the rad, removed the fan and installed twin e-fans, new stat, 5.9L hood, Going down the road idk 25mph+ with AC on/off, Towing or not the temp runs fine, right dead in the middle, But say i am moving around the yard slow or siting at a red light or drive through and it starts to overheat, Now it doesn't do it all the time but 99% of the time it does but there is a 1% chance it doesn't, once or twice i sat in a McD's lane for 5+mins and the temp not move, One thing i also notice is it idles at damn near 500RPM in gear or if its not in gear its alittle higher but only a pinch.

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Unread 07-07-2013, 08:55 PM   #2
jm8881
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Usually if you overheat while sitting still it's because of a lack of air flow. If you were to overheat while moving it would be due to an inefficient cooling system.

You say you have a couple efans but since the radiator isn't very big I'm wondering how large and how much air your fans move. Did you install them on the engine side of the rad or the grill side?
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Unread 07-07-2013, 09:06 PM   #3
airwolf9090
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Engine side, it was a tight fit for them one is set in the top passenger side and the other the lower driver side,

These are the fans that i have, Now i been thinking about getting a different set or one single large fan but these feel as if they move alot of air,

http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
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Unread 07-07-2013, 09:12 PM   #4
vonericsen
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I'm guessing that since you don't have a fan shroud those fans don't cover enough of the radiator to keep it cool sitting still.
I mounted a taurus 2 speed efan in the stock fan shroud and I don't have any overheating problems sitting still. Maybe you should go that route if you're going to change your setup.
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Unread 07-07-2013, 09:13 PM   #5
PolkaPower
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They are probably not pulling enough air.
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Unread 07-07-2013, 09:36 PM   #6
airwolf9090
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Okay, so tomorrow i will put the OEM shroud back on and see what she will do, I have afew e-fans laying around so if that doesn't do it i will try a single large fan on it,
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Unread 07-08-2013, 02:39 AM   #7
ErikTheRad
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I didn't look at the fans you installed (my computer doesn't wanna open the link) but keep this in mind.... with a radiator, its all about surface area. Theres a reason radiators are so big-- they need alot of surface area for pulling cool air across and dissapting heat. The AC condenser in your car and home work the same way, as does the evaporator coil. Large area, lots of air. It doesn't matter if you have a hurricane-force fan, if its too small and doesn't pull fresh air across a large enough area of the cooling fins, it ain't gonna do diddly beans. Think about the condenser on your home AC (if you have a split system its the unit that sits outside). 3 sides of that unit is all radiator while the large fan in the top draws in fresh air across the cooling fins, removing heat. Imagine if you had just a small 6" desk fan blowing air in one small focused area........ it ain't gonna do a damn thing. The radiator in your Jeep works exactly the same way.

Sorry if you already knew this, but if your fans are too physically small (regardless of actual CFM), thats likely whats causing your overheating.
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Unread 07-08-2013, 02:42 PM   #8
airwolf9090
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While i am doing this little bit of work i came across something to ask, The cooling fans are on a relay that is switch by a temp sender in the rad, Now i also need to set it where when the AC clutch comes on the fans come on as well, What wire should i tap for a source of power on the AC system? should i tap a AC switch that is located on the AC line above the engine or tap into the clutch power? If i tap one of them and when i have the AC off and the rad hits the temp to kick on the fans will it cause a feedback into the AC tap? Because they both would be connected to the same plug on the relay.
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Unread 07-09-2013, 12:58 PM   #9
airwolf9090
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^^^^^^
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Unread 07-09-2013, 02:28 PM   #10
jm8881
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You need some way of interrupting power to the fans when the ac kicks on so that you aren't sending power to the fans twice. I don't know if you have dual speed fans but a volvo 2 speed fan relay could work. speed one could be normal operation and speed 2 could be powered when the ac kicks on.
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