Minor heat issue
#1
Thread Starter
Junior Member
Joined: May 2018
Posts: 35
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From: SoCal
Year: '96
Model: Cherokee (XJ)
Engine: 4.0L
Minor heat issue
Did a shakedown trip to Hungry Valley last weekend and my new-to-me 96 XJ performed well given its age. Watching the OBDII on the way up alamo mountain, I am getting a bit hot on the trail and wanted to see what my next step should be to bring it up to code.
Idling for a few minutes with a warmed up engine the temp sensor will reach 222.8 before kicking on the e fan, bringing me down to 215-217 at idle. 725-825 RPM at idle between these temps. I know it should be 218, but i replaced the temp sensor with a dealer unit and it still kicks on at 222. could be a slow readout from the obdii (i only have idiot lights). Infrared confirms 220ish E fans as well.
10 mile pull up 7500 ft in the desert we hit 226ish before heading back down to 212-217ish. Stock suspension and tires. I see threads on here where lifted 33s on stock cooling components boast about never going over 210 even while wheeling in 90F weather.
Jeep does not overheat and runs 195-210 on the freeway and in traffic.
Previously, I flushed and burped the coolant (still bright green after 500 miles) throttle body/gasket/iac has been serviced. No exhaust leaks apparent and I can pull 17 mpg combined and sometimes up to 20 fwy.
Just doing preventative maintenance, I had already replaced the front temp sensor (ecu communication) o2 sensors, radiator cap, fan clutch (Stock) and E fan. I also replaced plugs/wires/rotor/cap. Was running the same way before. Is this normal? What should I plan for if I'm going to go ahead and overhaul the cooling system, I'm thinking the $400 aluminum mishimoto radiator could be a good investment when I'm ready since the 2 row mopar one is already $250. I believe in buy once cry once. I don't want to do a ZJ fan upgrade. already have a mopar water pump and mopar thermostat waiting to be put in. Considering the engine doesn't overheat at speed anywhere, I'm thinking it could be an airflow problem. I have the stock tow package tranny cooler in front of the radiator which is likely blocking some air flow.
Idling for a few minutes with a warmed up engine the temp sensor will reach 222.8 before kicking on the e fan, bringing me down to 215-217 at idle. 725-825 RPM at idle between these temps. I know it should be 218, but i replaced the temp sensor with a dealer unit and it still kicks on at 222. could be a slow readout from the obdii (i only have idiot lights). Infrared confirms 220ish E fans as well.
10 mile pull up 7500 ft in the desert we hit 226ish before heading back down to 212-217ish. Stock suspension and tires. I see threads on here where lifted 33s on stock cooling components boast about never going over 210 even while wheeling in 90F weather.
Jeep does not overheat and runs 195-210 on the freeway and in traffic.
Previously, I flushed and burped the coolant (still bright green after 500 miles) throttle body/gasket/iac has been serviced. No exhaust leaks apparent and I can pull 17 mpg combined and sometimes up to 20 fwy.
Just doing preventative maintenance, I had already replaced the front temp sensor (ecu communication) o2 sensors, radiator cap, fan clutch (Stock) and E fan. I also replaced plugs/wires/rotor/cap. Was running the same way before. Is this normal? What should I plan for if I'm going to go ahead and overhaul the cooling system, I'm thinking the $400 aluminum mishimoto radiator could be a good investment when I'm ready since the 2 row mopar one is already $250. I believe in buy once cry once. I don't want to do a ZJ fan upgrade. already have a mopar water pump and mopar thermostat waiting to be put in. Considering the engine doesn't overheat at speed anywhere, I'm thinking it could be an airflow problem. I have the stock tow package tranny cooler in front of the radiator which is likely blocking some air flow.
Last edited by msumms; 07-04-2018 at 02:49 PM.
#3
CF Veteran
Joined: Dec 2015
Posts: 2,139
Likes: 91
From: Syracuse, NY
Year: 1996
Model: Cherokee (XJ)
Engine: 4.0L
I have a 96, and your numbers are nearly identical to mine. They seem very normal. On those long climbs the transmission is getting very hot, and that is going to bring up the overall temperature. Efan coming on at about 220f is normal for the 96. Mine is the same.
The rising and falling temperature at idle is normally a fan clutch thing, mine did the same until I put a new fan clutch in. But it would seem you already did that. Perhaps that can be chocked up to your transmission cooler taking space, I don't know. Sounds counter-intuitive, but because you have 96 you can also turn on the AC when idling to have the efan on continuously. Or on long climbs. Yes the AC robs a little power, but I have found that it helps to keep the temp in a better range.
I tow a 2000lb popup, so I have pondered the same things you are now. I have an OBD2 digital dashboard (like you have no real gauges). So I'm keenly aware of temperatures as I attack long grades with the camper on a hot day.
The rising and falling temperature at idle is normally a fan clutch thing, mine did the same until I put a new fan clutch in. But it would seem you already did that. Perhaps that can be chocked up to your transmission cooler taking space, I don't know. Sounds counter-intuitive, but because you have 96 you can also turn on the AC when idling to have the efan on continuously. Or on long climbs. Yes the AC robs a little power, but I have found that it helps to keep the temp in a better range.
I tow a 2000lb popup, so I have pondered the same things you are now. I have an OBD2 digital dashboard (like you have no real gauges). So I'm keenly aware of temperatures as I attack long grades with the camper on a hot day.
#4
Thread Starter
Junior Member
Joined: May 2018
Posts: 35
Likes: 0
From: SoCal
Year: '96
Model: Cherokee (XJ)
Engine: 4.0L
thanks for sharing your experience. i thought maybe this was just normal. i don't like how it exceeds 220 for longevity sake, so i think i will fab a manual override switch for the e fan in the future.
and it seems in a similar thread a few days ago someone posted this about 00-01 cherokees. in my 96, my experience is exactly this. e fan turns on at 223 and turns off at 217. this described the system in 00-01 jeeps, however we both have late 96 models. here's the twist, my car has a new engine from jasper installed 40k miles ago. i don't think the engine would cause the e fan to kick on later since nothing else was replaced, and the engine is not a late model crate engine because it doesn't have the 0331 head. regardless, my 96 cooling system seems to be doing exactly what the 00-01 FSM says it should do.
and it seems in a similar thread a few days ago someone posted this about 00-01 cherokees. in my 96, my experience is exactly this. e fan turns on at 223 and turns off at 217. this described the system in 00-01 jeeps, however we both have late 96 models. here's the twist, my car has a new engine from jasper installed 40k miles ago. i don't think the engine would cause the e fan to kick on later since nothing else was replaced, and the engine is not a late model crate engine because it doesn't have the 0331 head. regardless, my 96 cooling system seems to be doing exactly what the 00-01 FSM says it should do.
Last edited by msumms; 07-04-2018 at 02:41 PM.
#5
CF Veteran
Joined: Jun 2016
Posts: 2,138
Likes: 278
From: Santa Clarita California
Year: 2001
Model: Cherokee (XJ)
Engine: 4.0L
I think I did the same run about a month ago and did not have any heat problems , I'm running the champion all aluminum 2 row radiator . been running it for over a year and no problems and it does have a life time warranty , when I installed it I also installed a new fan clutch .
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