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97 XJ starting to run hot

Ben824

NAXJA Forum User
Location
Woodstock, GA
Ok my 97 XJ with the 4.0L is starting to running a little mainly on the highway at about 220-225 degrees. I replaced the radiator and thermostat about 6 years ago with and all metal 3 row CSF radiator and a 185 degree thermostat. At idle it doesn't appear to run much over 210 only when I start to drive does it go up and hang around the next mark past 210. Could I need another new radiator and/or thermostat or is it somethin else? The fluid is a little dark but still very green and the water pump is only 2 1/2 years old and not leaking nor are there any leaks from anywhere.
 
Start by replacing your thermostat and get some fresh coolant in there. The importance of basic cooling system maintenance cannot be overstated.

6 years is a long time for a stat, unless you're not driving it much. I buy my stats from Jeep, and also like the Stant SuperStat. Go with the 195 degree stat. Get a new radiator cap while you're doing that.

If you still have fluctuation after that, the issue could be the radiator or water pump.
 
+1 birchlakeXJ. Just because your water pump is not leaking does not mean it is still good. If the impeller is eroded it will not leak, it just does not circulate. Use an IR thermometer and check the actual temperature at the t-stat housing. It could be a coolant temp sensor.
 
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And, don't forget the simple stuff. Fan clutch. If, when hot and you shut it off the mechanical fan spins easily, the fan clutch is suspect.

Also, don't forget airflow. Is the air conditioning condenser (radiator) plugged up with dirt, bugs, rocks, etc.)? It blocks flow to the radiator...clean it out (gently).

Airflow over the radiator is important....make sure you've got good airflow and good fan function first....Simple things before complicated (expensive) things!
 
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