What would cause my coolant temperature to read at or slightly above 210?

[mcoh1030]

Gomer should know OP is always checking for leaks!!! And I did prior to posting this. How often do you find yourself eyeing the underside of the engine compartment right after you park and your walking away from your Jeep? Checking if anything's leaking? Do it all the time. The leak wasn't obvious.

Like I said, I decided to let the engine warm up, at idle, to operating temp. I noticed the leak happening, just at the moment the temp. gauge reached 185-195. Then the temp gauge went up to 210 at idle, then went back down to 195. As soon as the temp. dropped down the leak stopped. I seems like the thermostat isn't opening when it should. It's just a guess. I did check the level in the expansion bottle and it looks to be full.

1) If the level in the expansion bottle is too full could that cause a problem?

2) Is the upper radiator hose connected properly? Should the hose go to the first STOP or the 2nd STOP, which is further down the hosing.

 

[JDS123]

After a cold start, the Jeep will get a little warm before the thermostat opens up and let’s the engine cool off. The temp behavior you’re seeing is normal.

I’d just clean up where the hose meets the thermostat housing and get it to stop leaking. Running a little over 210 on hot days at higher speeds is typical from what I’ve seen. My TJ does the same and it seems like many others do as well. I’d check the real temp through the OBD. If that is within reason, call it day after fixing the leak.

 

[mcoh1030]

Exactly how should the hose connect? Should it go to the first Stop or the 2nd?

 

[Flivver250]

The temperature you reported sounds normal, especially in hot weather. Besides finding the leak, when is the last time you pulled preventive maintenance on your cooling system? It never hurts to inspect every component and replace all that have question marks. Cheap insurance is a good flushing of the system, replacing the coolant and every belt/hose/clutch/etc that needs it or is original. At the age of the newest TJ, there should not be any original cooling system parts that can wear out. My Jeep hadn't overheated since I bought it, but I replaced the entire system to include idler and tensioner pulleys, pump, clutch, hoses, belt, sending uniit, T-stat and radiator. Overkill? Who knows? Running right, absolutely. Below is the flush I like.

https://www.amazon.com/gp/product/B00R74I5UY/?tag=wranglerorg-20

 

[mcoh1030]

I've never OVERHAULED the entire system. It's got over 150k miles on it and I'm the original owner.

I recently changed the water pump and the thermostat isn't too old. But it's at least 5-6 years old.

I never changed the Idler pulley or the Tension Pulley. Never replaced the fan clutch.

Belt, hoses, sending unit, radiator yes.......roughly within the last 7 years. I put about 7,500 miles a year on it give or take.

Yeah, I should set aside a day to wack out the whole system in one shot. Parts wise, I'm thinking it would come in at under $ 250, without rad, hoses or water pump.