05 LJ overheating during idling

[GoldenGorilla]

The 210 marker on the gauge is effectively a dummy guage. It's anywhere between ~190°F and ~230°F when showing "210".

It's possible your thermostat is like my original was last year. It was opening at 195 as designed, but too much and often staying open as actual temps were running 190°F on the highway. I wasn't overly concerned as failing open won't leave you stranded.

While doing the SPAL 850W fan mod and Edelbrock head swap, I changed to a Robert Shaw 330-195. It now opens at 195 as before, but controls opening and holds the temp higher as designed. I log 201°-208° and occassionally up to 221° when climbing up extended grades on I-70 into the CO mountains. All of that is normal and the gauge touches the 1 in 210 the whole time.

 

[mjbcomp]

The Hayden 2771 is the what most people replace their TJ fan with and is considered OEM replacement.. It is considered 'heavy duty' where the Hayden 2791 is considered 'severe duty'. Also the Hayden 2771 spins at 70% - 90% of the water pump shaft speed where the Hayden 2791 spins at 80% - 90% of the shaft speed. Either will work but i wouldn't replace a brand new 2771 with a 2791 "just because". And to mirror what others have said i don't think you're jeep is overheating at all. As long as that needle is 5/10% over/below the center line on the gauge you're good.

 

[GoldenGorilla]

The Hayden 2771 is the what most people replace their TJ fan with and is considered OEM replacement.. It is considered 'heavy duty' where the Hayden 2791 is considered 'severe duty'. Also the Hayden 2771 spins at 70% - 90% of the water pump shaft speed where the Hayden 2791 spins at 80% - 90% of the shaft speed.

Flip side of that.
The 2771 heavy spins faster unlocked at 25-30%
The 2791 severe spins slower unlocked at 20-25%
Usually they only lock in slow speed conditions.

Some scenrios one works better than the other.

In all scenarios the one that works is better than the defective one.

 

[TexasTJ2004]

I tried both 2771 and 2791. 2791 keeps things cooler. He is a little louder.

 

[MRChiefE7]

Thanks for all of the replies. Up until this summer I had not noticed the gage moving like it is. The system is full of MOPAR coolant 50/50.

 

[Strizzo]

can confirm mine does the same thing in the texas summer heat. Only time really i hear the fan clutch lock up is after sitting in a drive through or in traffic on a hot day with the a/c running WFO.