JK-linux

Without getting into a big drawn out thread on engine performance... does anyone have the actual part number for Autozone or Advance Auto for a decent 180 degree thermostat for a 2007~2009 JK 3.8L engine? I'd like to just go in and grab the part without yanking my tstat, bumming a ride, comparing sizes, etc...
Thanks,
Dave

JK-linux

Yeah, I checked and that's all I could find as well. All I know is that I read somewhere it's the tstat for another DC vehicle. For example, on the 2008 5.7L Charger it was a Dodge Caliber Motorad 4128 tstat for the required 180° part. The 4127 is the 5.7L 170° tstat. I just can't remember the part number for the 180° that fits the JK

JK-linux

I did some more looking and still no 180° option for anything close to the JK V6. I did find the dimensions of our thermostat: 1/13/16" x 3/4" x 61/64". With this V6, regardless of the vehicle type (mini-van, Jeep or sedan) and regardless of displacement or year Chrysler seems to have stuck with 195°. No aftermarket manufacturer, not even JET, seems to have an offering -odd since they make a Stage II chip that requires the 180° tstat. Anyone ever find one for our JK's in 180°?

JK-linux

Thanks for checking benmar. I ask because I picked up a JET Stage II for cheap. It really improved the shifts on my automatic equipped 2009. They state it is to be used with a 180° thermostat. Apparently none exist that I know of. Wonder how badly I'd roach my JK running the chip without the cooler tstat? I'd imagine the electric fans would just come on and run non-stop.

mikesjk

The number for auto zone to a 180* thermostat is 4208. Thats the only auto parts store that lists one for that temperature. hxxp://www.autozone.com/R,1649976/vehicleId,3117501/initialAction,partProductDetail/store,4401/partType,00047/shopping/partProductDetail.htm

JK-linux

Awesome. I'll give her a shot. Just about the exact size, just a longer spring portion by a few 1/10". I'll see if it fits and lowers the temp. THANKS! Has anyone tired this tatat out yet?

chuck45

If you do this let us know what the results are. The JK runs too hot for my taste and I'd like to lower the temperature some. In the desert in the summer I worry about it.

Does anybody know at what temp the fan kicks on? Is there a way to lower it?

If the temperature is successfully lowered is there a downside; other than upsetting the nanny-staters at the EPA?

ronjenx

I can't remember for sure, but i think the fan kicks on around 215 and shuts off around 190. That's idling in the driveway. Moving, it never kicks on. With the AC on, it hovers around 190, idling in the driveway.

Certain things happen in the computer programs at different temps as the engine warms up, but I don't know how big the "everything's OK" temp window is.

Read this and see if lowering to a 180 'stat is Ok:

Paraphrased from the manual...

Theory of Operation:
The PCM predicts what the engine coolant temperature should be, based on the engine coolant temperature at start-up, ambient temperature and how the vehicle is subsequently driven. The predicted engine coolant temp is compared to the Engine Coolant Temperature Sensor reading. The error between the two is calculated and integrated with respect to time. When the Thermostat diagnostic runs, the integrated error is compared to a calibrated threshold and pass/fail is determined. Separate pass and fail thresholds are used in order to improve accuracy of the diagnostic.

When Monitored:
With the engine running, ambient temperature between 17.6° F and 122° F, start up coolant temperature less than 122° F, and average vehicle speed greater than 10 mph until coolant temperature reaches 185° F.

Set Condition:
The PCM detects that the actual engine coolant temperature falls too far below the predicted engine coolant temperature and the predicted coolant temperature reaches the predicted target value before the actual coolant temperature reaches the actual coolant temperature target value. Two trip fault. Three good trips to turn off the MIL.

CIJeep

No, I don't know the temp setting for the switch, but switches/thermostats can be changed.

as to any detriments? You might find loss of power, loss of MPG and burned out exhaust system, but no one knows at this point how the computer electronics may respond. If you want to be the first guinea pig please let us know the sequence of events and how things went.

chuck45

Damn, it hurts my head to read that! Sometimes I think i'd like to pull the JK body and drop it onto the modified chassis of an old pre-smog pickup truck.....and get rid of all this electronics!

So does all this mean the 180 will cause problems?