So I spent some time on Saturday installing a 180 degree thermostat and flex-a-lite 183 e-fan. I'm pleased with the fan when it is running, but I am not pleased at all with the thermistor setup that activates the fan. Per the instructions, I stuck it through the radiator right in front of the inlet (upper) hose, and the thing never turns on consistently. Turning the pot on the controller all the way to the lowest setting causes the fan to cut on at about 88-89 degrees Celsius (as read by the EngCool reading on my Superchips programmer). It will drop the reading to around 87, but the fan never stops running as long as the truck is sitting. To be fair, I did not drive the truck at this setting, so the fan may have gone off while driving, but driving temps with the new thermostat were fluctuating pretty steadily between 87-88 Celsius.

Turning the pot towards the other end of the scale caused the fan to sometimes cut on at ~93 Celsius, but it wasn't at all consistent. The temp once rose to about boiling and the fan never cut on at all. So here are my questions: for those of you that used the thermistor, where did you place it exactly, and are my results typical of the way your fan operates? For those that did not use the thermistor, how do you activate the fan? I do not want to wire a manual switch in the cab, the fan should go on and off on its own as temperatures require it.

Also, my dumb *** forgot to record normal operating temperatures with my programmer before I changed my t-stat, but while driving I do know that the dummy gauge on the dash is lower than what it used to be. Can anyone with a way to read their engine coolant temps from the computer tell me what t-stat you are using, and what your normal temps are? Temperature used to sit rock solid at just below the middle mark all the time, and it now sits about half way between the lower and middle mark while driving, but raises back up depending on when the damn fan decides to kick on.

 

To be perfectly honest, I can't remember exactly where I stuck the probe as I installed mine in late '05. I know it's up near the top of the radiator, probably near the hose if that's what the instructions said. I'll have to look and/or take a pic when I am home this evening if it's not dark out yet.

Mine is pretty consistent though, I set it for about 175* 'ish and it turns on just before my 180* stat opens. Only difference is I have the 180 model as the 183 didn't exist then. Once running, my fan almost never turns off, only time is when it's relatively cool (and that'd be about 45* F or so here in the deep south) and I am running on the interstate where good cold air is coming in at decent speed.

Thermostat is the Jet, stainless with lifetime warranty is why I went with it. A little pricey, but what's $23 for a lifetime t-stat?

Once warmed up, my truck idiot gauge needle sits right at about 10 o'clock on the gauge and never budges, whether it's cool out, hot out or even when towing in the heat...

 

Good info as always Hammer, thanks.

Setting the fan for 175* isn't even possible for me. The lowest temperature I can get the fan to engage at is around 188* per my programmer, which I assume is taking the reading from the probe on top of the engine, right before the water exits to the radiator. Also, my t-stat is rated at 180*, but I think it's opening closer to 190*. However, since the water at the top of the engine, where the temperature is read, is hotter than the water at the bottom of the engine where the t-stat is, it's possible that's where the difference is coming from. I do not understand why they put the t-stat on the lower inlet instead of the upper outlet. Probably some emissions BS, but I do not care for this design.

Unrelated, but also something I'm curious about: when I was done installing the new t-stat, the system only took 2 gallons of coolant/water. Being at the bottom of the engine, I kinda figured all 4 gallons would have evacuated, and was hoping for it, since I'm rounding the corner on the 60k maintenance schedule and need to replace the coolant anyway.

 

PIA having the t-stat on the bottom. Hemi is at the top, three minute change. On my Grand Cherokee with the 4.7 it's a b*tch to get to...

 

Checking into this thread since I have a flex a lite 183 and jet 180 stat waiting for install.

How was the install? Did the overflow and washer bottles go back to their stock location using the supplied bracket? I ask due to my vararam intake which rests.on those bottles.

Post up some pics if you can.

 

I'll try and get some pics after work. Yes, the bottle(s) mount in the same way, using the supplied brackets. However, they are not in the exact same location as with the big-*** stock shroud. The new setup uses none of the stock mounting points for the reservoirs, as they are integrated into the stock shroud. Make sure you have a 36mm wrench available for the fan clutch nut, but other than that, nothing special was required to finish the job. Some people talk about using a spanner or other device to get the fan clutch off, but I just jammed a screwdriver into one of the holes in the pulley and then loosened the nut with the wrench. Wasn't difficult at all. I worked on it by myself, and really took my time, including soldering the large gauge power wires that connect to the controller and fan. I guess all-in-all it took me about 3hrs. Oh, and if you have the 4.7L and care about spilling coolant, you'll need a bucket capable of holding at least 2 gallons. Once you unbolt the t-stat housing, the engine flushes in just a couple seconds, and same with the radiator when you pull the t-stat out.

 

Good info. As long as the bottles are close I should be ok I think. I have a Hemi so t stat is on top. Hope you can get the temps figured out.

 

*bump*
Anyone else want to chime in on their average operating temps as shown by their programmers?
I really need to find a better place for that thermistor. After further testing, I have it turned to its lowest setting again. It seems it does not run when the truck is moving enough to keep the ECT at ~90*C. After stopping, it does not turn on until 94-95*C and cools down to 89-90*C, but does not ever turn off. I have also decided to replace the 180* thermostat I installed, as much research on the subject led me to the fact that Jet is the only company that makes a cooler thermostat that still functions in the same manner as the OEM unit. Apparently, our thermostat is not a traditional thermostat type, like nearly everyone has used in every engine ever. This is why it costs so much. Jet thermostats are not inherently expensive, they make plenty models in the $12-15 dollar range, just not for the dodge 3.7 and 4.7. So I'm going to try to track down a Jet locally and install it this weekend. So in the meantime, if any of you could post up your average 4.7L temperature with or without the 180* thermostat, it would be greatly appreciated. I have pretty bad OCD, and my MAIN goal is to keep that damn temperature gauge from moving around after warm-up.

 

Yeah, what a difference in pulling the t-stat on a Hemi and a 4.7. When I put the Jet in the Hemi, I used a paper cup and maybe lost 4 oz. of coolant in it.

I had the o-ring go on the stock t-stat in my Jeep (4.7 HO) last fall and replaced it with same (195*) and decided to just go ahead and do a flush at the time since most of the coolant was gonna come gushing out anyway. My luck, not a month later the side seam decided to split on my radiator and I had to go buy coolant all over again.

I guess that's one nice thing about the Flex-a-Lite 180 kit, I just mounted it inside the stock shroud, fit like a glove and only needed 4 self tappers in the sides to hold it in place. Didn't have to mess with the bottles at all...

 

I had to take the bottles out, but it's not hard at all, and no fluid was lost doing that. If all I had done was the efan, no coolant would have been lost at all. The install is a no-brainer until you get to the wiring.