Modified XJ Cherokee Tech XJ (84-01)
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Overheating with AC on only

Old 02-20-2019, 08:30 AM
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Default Overheating with AC on only

Long story short, my xj overheats when the AC is on only. Whe the ac is of temp hardly reaches 210 normaly 200. Outside temperature goes above 100 normaly and having the ac off is not an option. I have checked if electric fan runs while the ac is on and it does, actually the e fan is always on since it is conected direcly to the battery. I have put a new zj fan clutch and that is working great so Im not really sure if the e fan is blowing as strong as it should or if the condenser is making the rad hotter, already tried cleaning it but same problem.
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Old 02-21-2019, 05:40 AM
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Sounds like a radiator issue to me. ever replace the cap?
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Old 02-22-2019, 11:12 AM
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Originally Posted by cruiser54 View Post
Sounds like a radiator issue to me. ever replace the cap?
Radiator is brand new 2 row. Water pump is brand new as well same as the thermostat and tstat housing. The rad cap says 1.3 bar which is ahout 18psi. The cap came with the rad but I have not changed it.
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Old 02-22-2019, 11:35 AM
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test the new cap.
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Old 02-22-2019, 11:36 AM
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Originally Posted by cruiser54 View Post
test the new cap.
Do you suggest a 18psi or should i go a little bit highter
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Old 02-22-2019, 11:37 AM
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NOT higher!! I think 13 is stock, but some folks use 16.
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Old 02-25-2019, 07:47 AM
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Have you checked that efan is blowing air into the engine compartment and not the other way around, as you mentioned it is connected directly to the battery and not the OEM wiring it could be incorrectly wired (happened to my brother once)
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Old 02-25-2019, 08:07 AM
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Originally Posted by lualchro View Post
Have you checked that efan is blowing air into the engine compartment and not the other way around, as you mentioned it is connected directly to the battery and not the OEM wiring it could be incorrectly wired (happened to my brother once)

Excellent thought!!!!!
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Old 02-25-2019, 08:11 AM
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Originally Posted by lualchro View Post
Have you checked that efan is blowing air into the engine compartment and not the other way around, as you mentioned it is connected directly to the battery and not the OEM wiring it could be incorrectly wired (happened to my brother once)
Yes it is blowing to the engine compartment. Id have to try changing the rad cap since it is a 18psi cap, some say it has to be lower
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Old 03-01-2019, 01:05 AM
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Check the fan clutch
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Old 03-01-2019, 03:01 AM
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Originally Posted by Jmet8 View Post
Check the fan clutch
It is brand new
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Old 03-01-2019, 11:43 AM
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An 18lb cap is too high. The higher the pressure, the hotter it will run. Switch to a 16lb radiator cap. Use a standard cap, not the ones with the lever on it. The only brands i trust are OEM or Stant (this includes thermostats). The only other things i can think of is the a/c seizing up a bit once engaged making the engine work harder, or the block needs a flush, or the gauge is off for whatever reason. Check the temp with a IR gun pointed at the thermostat housing to be sure its reading properly.
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Old 03-18-2019, 03:09 PM
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Originally Posted by fb97xj1 View Post
An 18lb cap is too high. The higher the pressure, the hotter it will run. Switch to a 16lb radiator cap. Use a standard cap, not the ones with the lever on it. The only brands i trust are OEM or Stant (this includes thermostats). The only other things i can think of is the a/c seizing up a bit once engaged making the engine work harder, or the block needs a flush, or the gauge is off for whatever reason. Check the temp with a IR gun pointed at the thermostat housing to be sure its reading properly.
So I have replaced the rad cap for a 16psi one, also replaced the efan and tsta housing and now im using a 195f tstat, put on some silicone hoses as well as replaced the water pump. Im running a 3row rad also put a transmission cooler and temp is still going up to 230f. I bought an IR gun and pointed it at the tsta housing and says temp is 211f so maybe my gauge is not giving good readings, besides that how high can the temp go before the engine goes off by itself?? Im thinking i should not go as high as 230.

Thoughts?
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