I have a 1999 4.0 SE model. I have flushed the system a few times with a hose fitting that I installed on the top heater hose. The thermostat remained in the Jeep when I flushed it. Question-Should it be removed when a flush is done? I replaced the thermostat about a month ago with a 195 degree unit. The Jeep still ran hot.
After all that I replaced the radiator and water pump. Also the fan clutch, from NAPA.. It was a standard radiator nothing fancy. The water pump came from NAPA I drove it around the neighborhood and it started to redline. The electric fan came on.I took an IR reading at the thermostat sensor area and it was 238 degrees. My top heater hose was very hot and the top radiator hose was hot.
The radiator was Cold!!, I was able to touch it and didn’t really feel any heat. The bottom radiator hose was cold also...
I was thinking about removing the thermostat and riding around to see what temperature it gets to. If the thermostat is not working correctly would it cause this problem?
Any ideas would be appreciated.
I would rather work on the Jeep than rake leaves today!
Ambient temperature here in Atlanta is upper 60’s today
Thanks for reply’s,
Kevin

 

The hoses are getting hot, but the radiator is cold. Buy another radiator.

 

Dang, it took a while to change it out. This is what I used; I got it off amazon. I think other people have used this type with success.Any chance it could be anything else?

 

That sounds like a stuck thermostat to me. Or tons of air in the system.

 

I was at Home Depot and a gent pulled up in a Cherokee so I latched on to him with questions. He mentioned air in the system so when I got home I put the Cherokee on some ramps and I squeezed the lower radiator hose and air burbled up. I let it run more air bubbled. I added more coolant. I let the Cherokee get to 210 with an ir test at the sensor. Then I turned it off and felt the radiator. I reached to the lower part of the radiator and it was HOT. The top part of the radiator was cool.
does the transmission cooling lines run through the top of the radiator? Is this why when I first felt the radiator for coolant heat I was feeling the wrong part of the radiator. Is the top half for the transmission and bottom for the engine?

 

The transmission cooler is entirely within the driver side endcap of the radiator. It doesn't go side-side.

 

Did you change the heater hoses? Might have them backwards. I did this on my '66 mustang and it ran pretty hot. Once I got it right...no more problem.

 

I did not change the heater hoses or heater core. The top heater hose is from the top firewall fitting to the top right thermostat cover fitting. The bottom firewall fitting to the water pump is where the other hose goes. I think this is correct. Please let me know if it is not. I was able to remove some more air from the system last night and I ran it for a bit in the driveway. When I looked at it this morning it had sucked some coolant from the reservoir. I am going to test drive it some this morning and I will report on its performance now that I have gotten some air out of the radiator.

 

"The top heater hose is from the top firewall fitting to the top right thermostat cover fitting. The bottom firewall fitting to the water pump is where the other hose goes. I think this is correct. Please let me know if it is not."

I'm not sure on this part, but if you get it backwards on some cars....they will run hot.

 

What was i thinking? I wasnt lol. You didnt buy another one, did you? My Mustang went thru the same after replacing the thermostat. The upper hose was hot, but the lower hose and radiator were cold. It just needed burped.

 

Perhaps you have the wrong waterpump, one with a reverse flow?
www.youtube.com/watch?v=AK44aYNHtYY

I like using this to bleed the air from the system.
http://www.amazon.com/EPAuto-Radiato...5362009&sr=8-1

 

I did not buy a new radiator. I put the Jeep up on ramps and ran it for awhile, let it cool off and reached down and squeezed the lower radiator hose. Air bubbled out. I added more coolant and did it again. I let it sit overnight and topped it off.Then I took it off the ramps and drove it around some. The day was cold and it was not overheating... An ir reading at the thermostat was around 200 degrees. The reverse flow water pump idea gave me a sinking feeling there. I did not check the impeller design before I installed it. I watched the YouTube video on that reverse impeller and will check the pulley and I have the box and old one to look at.
I had to go out of town for a few days so I won’t be able to mess with it for a few days. I will report back on the performance when I get back in town.
Thanks for everyone’s ideas and help with this!
Kevin

 

One trick that I learned, was to drill a small hole in the thermostate on the side. It lets the air bubbles out during a normal heat cycle. I do that on the older vehicles that I have. '82 vette/'66 mustang/ and will on the jeep. No need to burp after that...

 

I got back in town Friday night and I drove the Jeep around Saturday. It did not overheat! I think the help I received on this forum and the new parts installed took care of the issues. I would like to thank everyone for their help with this. Could not have done it without y’all.
Now to work on the 10 mpg next....

 

Drill it a 12 o'clock.

Or, better yet, buy a Mopar stat.