Normal Operating Temp

A

akorna

New member
I purchased a '99 XJ 4X4 4.0 automatic last week and I'm going through the vehicle now to catch up on the maintenance.

I noticed that the temp gauge hovers near or on the 210 degree marking on the gauge. Seems a little high if the thermostat is 195. What is "normal" for a Cherokee 4.0L?

Thanks for any feedback!
 
Considering water boils at 212 deg. Now you have antifreeze under Pressure, That will take about 230-240 to boil. So ya I'd Say thats about right too give ya heat in the winter. You could go as low as a 160 deg stat, But You will get less heat..
 

Hi,

The 6-cylinder engines do have a normal operating temperature of about 210 degrees F.
It is fine :mrgreen:

-Nick :!:
 
Hi, I was going to post a similar thread. My 91 YJ (with a 4 banger) had an operating temp of 210°F. I just replaced the thermostat (and heater core and their hoses along with a rad flush) with a 180°F variety. Now my operating temp has dropped to about 185°. I assume this is because of the thermostat change (and possibly the other cooling system replacements). Is that the correct assumption?
 
White said:
Considering water boils at 212 deg. Now you have antifreeze under Pressure, That will take about 230-240 to boil. So ya I'd Say thats about right too give ya heat in the winter. You could go as low as a 160 deg stat, But You will get less heat..
Click to expand...

My first YJ had a 160 and the heat was non existant on a cold day on the highway. I changed it to a 195 deg and all was well again.
 

Thanks for the responses - 205-210 degrees just seems to be much hotter that any of my other vehicles are running. I might consider going to a 180 degree stat - don't know if that will cause a trouble code to set.
 
According to every jeep forum I've been to, 210 is exactly where the 4.0 is designed to operate. I don't think you should mess with that.

You are right, it seems high, but it's correct.
 

White said:
At what temp is it designed to leak oil all over the dam place ? :lol:
Click to expand...
What ever temp the Jeep is operating at. :D
 

210 is normal on these
But......
It more depends on where you live and the driving conditions your in. And if your vehicle is stock or not Ive had to switch to an upgraded water pump and a 160 tstat. I drive in heavy traffic in the bay and would push 220 while sitting in 110 weather.
But wasperfectly fine before i added ss racing headers and short ram intake
The cooling system in these things is great at doing its job when the engine is stock

Its once you start upgrading when you have issues
 
91xjmudder said:
210 is normal on these But...... It more depends on where you live and the driving conditions your in. And if your vehicle is stock or not Ive had to switch to an upgraded water pump and a 160 tstat. I drive in heavy traffic in the bay and would push 220 while sitting in 110 weather. But wasperfectly fine before i added ss racing headers and short ram intake The cooling system in these things is great at doing its job when the engine is stock Its once you start upgrading when you have issues
Click to expand...

This is an old post.

FYI you need to run a 195 deg thermo. The temp will run at 210 and the PCM will adjust the air fuel to try to attain 210. By running 165 you are not allowing the engine to come to temp and gain the efficiency it can reach.

I doubt the intake and headers directly caused you to run hotter. A intake or exhaust leak will. You may want to be sure the clutch fan is working properly, there are no leaks in the cooling system where air can get in. Your rad cap is 18# and operating. Also verify your water pump is circulating and the radiator is not blocked internally or external.110 can be brutal esp crawling or standing in it.
 
Try to get the temp to 195 and you will get better gas mileage and reduce engine wear. running below 195 will cost you gas money and running above 195 will be not good for your engine.
 

What is the normal operating temperature be for a 2004 Cherokee 4.7. Would that also about 210 ?

This weekend I will be replacing the Thermostat, thermostat sensor, radiator cap and doing a radiator flush. hopefully this will resolve the over heating issue.

I have been noticing my clutch fan as been coming on more often.

Thanks.
 
Last edited:
Changed out the thermostat and put in new Hout coolant as recommended for use on Jeeps/Chrysler vehicles. Still getting thermostat gage going up to 260 and the back down a little over 210 and every where in between. Monday will be putting in a new sensor and if that doesn't solve the issue then radiator flush which I didn't want to do in the middle of winter. :-/ any other suggestions on what else could be causing this issue ? I'm leading towards the thermostat sensor misreading.
 
Was the thermo broken?
Do you have any leaks?
Does your heater work?
Replacing the temp sensor is not a bad idea. You could check it by pulling it and placing it in water your heating and monitor the resistance with a multi meter. The resistance change should be steady and consistent.

At 260 it should be boiling out of the radiator into the overflow.
Is it?

If fluid is boiling into the overflow it is overheating.

Consider changing the radiator cap. Be sure it is 18 lb. refill burp and check again if it boils onto the

Did you burp all of the air out of the system? Air trapped at the thermo and temp sensor allows for the fluid to boil. The air becomes steam and you will see the temp jump.

While burping you should get 25 or so big bubbles out. If there is a constant stream of tiny soda bubbles there is another issue.

Check your oil and note the color. Also pull your filler cap and look at the underside. Do either look like chocolate milkshake?


Does your exhaust smell sweet like antifreeze?


Regards,
JPNinPA

Sent using TapTalk
 
Last edited:

The thermostat I don't think was broken, but replaced it anyways. Also I don't have any leaks and do have heat coming out when turned on. The gauge just goes from anywhere 195 to over heat and then back down to about the 195/210 area and then sometimes back up to the 250/260 area again. Haven't smelt the exhaust yet and oil looks fine and very black so don't think there is a coolant leak gasket issue. I do have a weird yellowly goob some sort under the oil cap and down the sprout where you add the oil in that I'm not sure of. But the dip stick comes out clean and oil changes are always black oil. Going to replace the thermostat sensor and get a new radiator cap on Monday 1/16 and if it isn't too cold do a radiator flush. Possibly replace the relay as well.
 
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