I have both fans. And it still overheats. Doesn't loose water. New t-stat, new-ish water pump, new heater core. I'm not sure what's goin on with it.

 

Fan clutch most likely. I had the same issue, replaced the fan clutch and all was good.

 

If you do need a new fan clutch pay the bit extra and get the mopar one from the dealer or online somewhere. The aftermarket ones are way too aggressive so they stay engaged for too long and will cause a noticeable drop in mpg and power. I had to return 3 separate ones from 3 separate stores until I just gave up and did the full electric swap.

 

I'm actually looking into a t-bird fan. They are the same as the mark VIII but easier to find in my area. Called and found one for $50 at a junk yard. Prob gonna go pick it up today.

 

The GC fan is suppose to pull as much air as the markIII fans. You have to find the specific part number. I posted this on another thread regarding the efans. you can find it there.

If you have the original oem efan, you're in luck because the power plugins are the same on the gc fan and you can replace the oem fan with the gc fan.

 

Honestly thinking about talking Dad into at least adding a helper e-fan like the 00 and up have. Their 99 with only the mechanical fan does let the engine get pretty warm on the really hot days (that'd be 90s in Denver). I'll be at a red light and the gage just creeps up and up... My 01 with the 4.7 (stock setup with both fans) only barely moves the gage on the hottest days from where it normally runs, and I'm pretty sure the e-fan is the difference.

 

I installed the thunderbird fan today. Worked great, I got pics and will do a write up soon.

 

You need big fan, obviously

 

DFW now touching the 100+ temperature mark. The OEM electric fan is doing a good job maintaining 180 on the highway. Does a decent job and holding it around 200 when slow moving. Now sitting idle, it will hold it just under 210.

If the A/C is turned off, the temp will drop back to 180. Just not quite strong enough to hold 180 if the A/C is turned on.

I just bought these dual 10 inch hi performance efans that is made for a older generation Jeep Cherokee.

http://www.ebay.com/itm/281110386954...84.m1423.l2649

These dual jeep 10 inch fans will be installed in front of my a/c condenser to apply additional cooling on the upper half of the radiator where the OEM fan cannot reach. The OEM fan covers more the lower part of the radiator.

These dual Jeep 10 inch fans have a very thin height (2.25 inches). I measured the distance between the front grille and the A/C condenser and got just barely over 2.5 inch clearance so these fans will clear the front grille when you close it.

These fans are rated at 1250cfm each and only draws about 8amps of current each. When configured for push, I estimate the cfm may drop to around 800-900. But more than enough as they are supplementing my OEM fan.

I want my truck to hold at or near 180 during Texas 100+ heatwave coming soon if not already here.

 

The dual 10's are installed on front of the condenser and set the polarity of the fans to push mode. I had to add 3 washers to push the grill outward by 1/4 inch so the grill will not rub against the fans when I close the hood. I can feel the air being pushed into the condenser/radiator. Noticed alot more air flow on the back side of the radiator.

The Truck will still eventually overheat during slow to sitting still traffic. Temp is kept around 185-190 when driving on the highway. Temp reached as high as 230 Degrees when sitting still or driving slow (under 40mph). I got my OBDII scanner installed to monitor actual temperature. the temp gauge on the dash is way off. If the dash says 210, OBDII scanner says 220. With the addtional dual 10 inch fans to assist the OEM fan, the temp still overheats but takes longer to reach it. As soon as the A/C is turned off, you can see the temp eventually drops back to around 186-190 with A/C turned off. This is also true before I added these dual 10 inch efans.

the OEM Efan has 8 to 10 blades and I assume it has to pull around 2000 cfm's. I can really feel the air blowing out the back and can feel the air pulling thru the condenser/radiator before I added the dual 10's. I never had any overheating issues using the OEM Efan during the fall/winter/spring and now summer. It wasn't until summer when temperatures above 90 degrees that the Efans cannot maintain temperatures when using A/C.

I guess these 5.9's really need monstrous cooling to keep cool when idling or driving slow. I refuse to put the clutch fan back on as the clutch is a severe aftermarket and it takes about 8-10 miles of driving to force the clutch to disengage. My only option left is to purchase a mopar oem clutch or try the specific high power E-fan from the Grand Cherokee to see if it gives me the additional boost on air flow.

Things to eliminate if you guys ask:

Radiator: New, only a couple years old
Antifreeze: 60/40 mix clean and replaced every 2 years
Water pump: New, about 3 months old
Themostat: new, just replaced to see if it can stop overheating. (Can see antifreeze flow very well with new stat)
condensing coil and radiator power flushed. You can see clearly thru the coils before installing dual 10 inch fans.

Next thing I will try is possibly retune my 5.9 back to stock settings to see if the stock settings will cool down the engine. Currently tuned on race mode.