I do believe Metlic53 is spot on regarding "the loops and O2 function". Heated O2s will reach operating temp within seconds of motor start-up and the loop closes when they do. Our ScanGauge shows closed loop well before the motor reaches "so called" normal operating temp.

 

Really? I'm missing my top shroud and the side one isn't in. How much of a degree difference could that make?

 

Why did you even come on here to ask every ones opinion if all you are going to do is argue about everything anyone has to say. People like this are just a waste of time to try to help since they think they know everything and just ask a question so they can complain!

 

The FSM says (except for test purposes) DO NOT operate without a t-stat. My guess is the "so called" normal operating coolant temp range is 160F-218F. With OBD-II, if coolant temp does not reach 160 in X amount of time after motor start-up, a CEL will be set and the ECU is programmed to turn the efan on at 218.....thus normal could be construed as anywhere between 160 and 218. Nowhere in the FSM is 210, or any other temp for that matter, referenced as "normal operating temp".

 

The T-stat only determines the lowest temperature the motor will see.
It has nothing to do with the temp after it opens. Unless of course it's stuck.

Removing it just keeps it from reaching operating temperature when it's cold - no real effect when hot.

The heated sensors force it into closed loop faster - yes.
But the engine running colder than it should hurts mileage and helps create sludge.

Open loop only means the O2 sensor inputs are ignored and a set of hard parameters are used.
Closed loop means it can monitor itself and adjust the mixture and timing to the best settings as you drive. Mileage and emissions are controlled when in closed loop.

For example - close your eyes and drive - open loop.

Open your eyes - you see where you are and can adjust where you are going - closed loop (another way of saying "feedback.")

The Cherokee cooling system is marginal at best. Most any weakness makes them run hot.

 

If your jeep is still hitting 180 plus without a t-stat in then there is a much bigger problem.

 

I don't think that's always correct, especially this time of year. T-stat determines minimum temp, like rrich said, the rest of the cooling system components, their condition, ambient temp and driving/operating conditions determine max coolant temp. Once coolant temp reaches +/-15 degrees above the t-stat rating, the t-stat is wide open, thus acting like no t-stat. The weak link in the XJ cooling system is the dinky radiator....small sq. inch surface area per cubic inch displacement.....something like 1.27 sq. in./cid.

 

I've read also that running without a t stat can cause undue wear on your engine. The closer to the t stat the more damage. I myself wouldn't run without it...... Unless you are stranded on the side of the road then. But that's just my two cents..... It's your XJ do what you will with it......
Just wouldn't recommend it. My XJ had erratic temp fluctuations and I replaced my fluid ,e fan ,clutch fan shroud and t stat (195*) Now she sits pretty at around 200* no matter the temp outside. Worth looking into. But again,just my two cents..... to each their own.

 

You're funny, i could ask you the same thing. Why Post if your not going to post your thoughts on the subject? and i only argued about the open loop thing the guy said because he was incorrect.

 

All three of my xjs (89-97-98) dont get near 180 without one. They get around 160, but i am in the pnw so its cooler then most places.

Running to cool is a bad thing for a engine, why do you think you let it warm up before you drive it (assuming you care, somthing tells me you dont) It does put extra wear and tear on your engine, it can lead to a tired, worn out engine sooner then it would have if it was running at operating temp.

 

i don't think anyone lets their car warm up to operating temperature before they drive it, a select few. the jeep i took it out of only sees trails, and its 100 plus degrees here and so humid, i drive it on the street and it heats up to 190 within 5 minutes, it rarely goes over that. runs perfect now that the pulley was replaced. There was nothing wrong with my t stat so i can run one now if i want.

 

I do, i just like to treat my rig nice. If its just a beater wheeler then screw it, but i hope its not the XJ in your avatar because that looks way to nice to not give a **** about.

 

The one in my avatar is my daily driver, I have two others that are trail only rigs. Do I let my 97 warm up to 190 before I get on the freeway? No, it has a 160 t stat and runs alot better than with the 195 thermostat

 

The quickest way to warm the motor up is to drive the vehicle. Idling wastes gas and pollutes.

 

Good for you guys for saving the planet by not letting your JEEP warm up LMAO