Okay, I have read every thread I can find on the XJ cooling system and I am still stumped.
My new to me, 1997 XJ does the following: It runs great around town and 95% of the time on the freeway with the temp guage at around the 210 mark. But sometimes, usually when under load the temp needle jumps just to first line of the red zone on the guage and the check guages light comes on. I can either pull over or keep going and the guage stays right at the first part of the red zone on the guage for approximately 40 - 60 seconds and then jumps immediately back to the middle of the guage at 210 or so. It will keep repeating this cycle until I get off the freeway. The system does not boil over and the engine does not change the way it runs (it runs good).
- I am not using any coolant.
- I have a CSF Radiator (the sticker on the bottom says J16825310)
- I have a Champion Radiator Cap
- Coolant is Clean
- Lower Radiator Hose as the spring in it.
- All hoses look good are probably new within the last year.
- The Coolant in the fill bottle doesn't change levels.
- The Coolant looks to be 50/50.
What I have done so far:
- I have looked over the entire system for leaks and found none.
- I just replaced the Champion Radiator Cap with a Mopar Part #52079880AA.
I haven't tested the system with the new radiator cap yet, but will do so tonight. If I still have a problem I will try replacing the thermostat. I am suspecting the thermostat due to the strange cycling issue. When I do the thermostat I will also try find an incline and run the engine without the cap and with the rear temperature sensor loose in order to evacuate any air in the system. What else should I do? Am I on the right track? Any help would be greatly appreciated.
My new to me, 1997 XJ does the following: It runs great around town and 95% of the time on the freeway with the temp guage at around the 210 mark. But sometimes, usually when under load the temp needle jumps just to first line of the red zone on the guage and the check guages light comes on. I can either pull over or keep going and the guage stays right at the first part of the red zone on the guage for approximately 40 - 60 seconds and then jumps immediately back to the middle of the guage at 210 or so. It will keep repeating this cycle until I get off the freeway. The system does not boil over and the engine does not change the way it runs (it runs good).
- I am not using any coolant.
- I have a CSF Radiator (the sticker on the bottom says J16825310)
- I have a Champion Radiator Cap
- Coolant is Clean
- Lower Radiator Hose as the spring in it.
- All hoses look good are probably new within the last year.
- The Coolant in the fill bottle doesn't change levels.
- The Coolant looks to be 50/50.
What I have done so far:
- I have looked over the entire system for leaks and found none.
- I just replaced the Champion Radiator Cap with a Mopar Part #52079880AA.
I haven't tested the system with the new radiator cap yet, but will do so tonight. If I still have a problem I will try replacing the thermostat. I am suspecting the thermostat due to the strange cycling issue. When I do the thermostat I will also try find an incline and run the engine without the cap and with the rear temperature sensor loose in order to evacuate any air in the system. What else should I do? Am I on the right track? Any help would be greatly appreciated.