Overheating issues
Thread Starter
Member
Joined: Sep 2018
Posts: 216
Likes: 8
Year: 95
Model: Cherokee (XJ)
Engine: 4.0L
Overheating issues
So, I live in a place where outside temp goes as high as 108F during the day and average temperature is 98F.
I have installed a 3 row radiator, changed the water pump and removed the thermostat, as well as replaced the fan clutch and main fan, however my XJ still goes higher than 210 and eventually shuts off by itself and wont let me start until it cools down.
I'm going to regear from stock to 4.56 and don't know if that would change anything
Does anyone have any suggestions?
Ps. It rains really really heavy during rainy season and hood vents would mean a lot of water going in the engine compartment.
I have installed a 3 row radiator, changed the water pump and removed the thermostat, as well as replaced the fan clutch and main fan, however my XJ still goes higher than 210 and eventually shuts off by itself and wont let me start until it cools down.
I'm going to regear from stock to 4.56 and don't know if that would change anything
Does anyone have any suggestions?
Ps. It rains really really heavy during rainy season and hood vents would mean a lot of water going in the engine compartment.
Junior Member
Joined: May 2018
Posts: 35
Likes: 0
From: SoCal
Year: '96
Model: Cherokee (XJ)
Engine: 4.0L
check for head gasket leak. not common in '95s though. use a thermostat from mopar dealer. 180 or 195. engines overheat without a thermostat; someone smarter than me will tell you why. flush the coolant really well. and the heater core. bypass the heater core if it's trashed. bypass the radiator for your trans cooling. replace the temp sensor, mopar. install an aux fan override and have it going all day every day. 100F is really hot. it's going to be hard on that engine, which already runs hot from the factory. i went to a greater capacity radiator and it solved all problems (mishimoto). none of this is guaranteed. you throw money at it until it's fixed. i started small and finished big with the $400 mishimoto rad.
Last edited by msumms; Jan 26, 2019 at 09:36 AM.
Thread Starter
Member
Joined: Sep 2018
Posts: 216
Likes: 8
Year: 95
Model: Cherokee (XJ)
Engine: 4.0L
check for head gasket leak. not common in '95s though. use a thermostat from mopar dealer. 180 or 195. engines overheat without a thermostat; someone smarter than me will tell you why. flush the coolant really well. and the heater core. bypass the heater core if it's trashed. bypass the radiator for your trans cooling. replace the temp sensor, mopar. install an aux fan override and have it going all day every day. 100F is really hot. it's going to be hard on that engine, which already runs hot from the factory. i went to a greater capacity radiator and it solved all problems (mishimoto). none of this is guaranteed. you throw money at it until it's fixed. i started small and finished big with the $400 mishimoto rad.
Did you try any other type of aluminum radiator before the mishimoto?
Senior Member
Joined: Aug 2009
Posts: 914
Likes: 14
From: north carolina
Year: 2000
Model: Cherokee
Engine: 4.0
Maybe you've got a blockage somewhere, and coolant flow is restricted. I would make sure to flush the entire system out. Also don't forget the transmission is cooled by the same system, so that could cause temps to rise too.
CF Veteran
Joined: Oct 2018
Posts: 1,096
Likes: 166
From: Hunt County Texas
Year: 1995
Model: Cherokee (XJ)
Engine: 4.0L
Well i dont understan why should i put a thermostat if its always hot out there and the engine is always running hot, I had a MotoRad thermostat installed but decided to remoe it as it did not make much sense to have one in the firts place.
Did you try any other type of aluminum radiator before the mishimoto?
Did you try any other type of aluminum radiator before the mishimoto?
Thread Starter
Member
Joined: Sep 2018
Posts: 216
Likes: 8
Year: 95
Model: Cherokee (XJ)
Engine: 4.0L
Temp raises to 108 outside, coolant would never "sit"
Junior Member
Joined: May 2018
Posts: 35
Likes: 0
From: SoCal
Year: '96
Model: Cherokee (XJ)
Engine: 4.0L
I did not replace the radiator until I went to the mishimoto. So the radiator probably isn’t your issue.
of course the coolant would sit with a t stat. As it should. If it’s 108 outside your car will start at 108. And then it will hit 195 and the therm will open. It opens gradually allowing coolant to sit for longer at the radiator before fully open. If the coolant is being partially restricted at operating temp as it should be, it will be getting exposed for a longer period of time to air moving in front of it at the radiator; and therefore cooler by the time it reaches your engine. You should always run a t stat. But that may not be your issue if you were already overheating. However you won’t know if you’ve fixed the problem if you’re still overheating due to no tstat.
I think you have a blockage somewhere. Sometimes you have to flush these things 10 times. It can be at the heater. It should burp on its own for the most part. On older systems you need to let it run with the cap off and the heater blowing. Speaking of which, are you getting choking hot heat? Check at night when it’s cooler. It should be blazing hot at full blast when your engine is up to temp. In your climate you need an aux trans cooler. The hot trans fluid in the radiator transfers heat to the coolant nearby.
Good luck. This drove me crazy. I never overheated while driving, but at idle and low rpm it would
kick up to 225 before the aux fan could control it. My process was:
reverse flush coolant many times. This helped slightly.
replace fan clutch. No help.
replace aux fan. No help.
replace both temp sensors with dealer parts. No help.
replace old crusty ccv valves. No help.
replace many rad caps.
flush and burp the **** out of the coolant again. No help.
replaced t stat w dealer 195, dealer water pump, and replaced the mopar hd cooling radiator in there from PO with mishimoto aluminum. Now sits at 210 like a rock in SoCal summer. On desert climbs in 4x4 it will rise a bit. 220 is ok. On obdii it’s even cooler since the temp sensor for the computer is at the front of the engine. In fact, once it hits around 210-12 at the gauge, the temp will actually fall slightly back down, even at idle. That’s the t stat opening up more, and the cooler water rushing in.
I have a stock mopar trans cooler that was part of the towing package.
Before this odyssey I would regularly hit 223 at idle or higher. Once I hit 235 on a climb and decided that was it time to pull the rad, pump and tstat. Never had an issue since and I’m running the xj clutch. Now on long climbs I can hit 220 or so but I’m talking 7k feet of climbing nonstop at low rpms, on unpaved hardpack and washboard with my tires at 12-15psi
of course the coolant would sit with a t stat. As it should. If it’s 108 outside your car will start at 108. And then it will hit 195 and the therm will open. It opens gradually allowing coolant to sit for longer at the radiator before fully open. If the coolant is being partially restricted at operating temp as it should be, it will be getting exposed for a longer period of time to air moving in front of it at the radiator; and therefore cooler by the time it reaches your engine. You should always run a t stat. But that may not be your issue if you were already overheating. However you won’t know if you’ve fixed the problem if you’re still overheating due to no tstat.
I think you have a blockage somewhere. Sometimes you have to flush these things 10 times. It can be at the heater. It should burp on its own for the most part. On older systems you need to let it run with the cap off and the heater blowing. Speaking of which, are you getting choking hot heat? Check at night when it’s cooler. It should be blazing hot at full blast when your engine is up to temp. In your climate you need an aux trans cooler. The hot trans fluid in the radiator transfers heat to the coolant nearby.
Good luck. This drove me crazy. I never overheated while driving, but at idle and low rpm it would
kick up to 225 before the aux fan could control it. My process was:
reverse flush coolant many times. This helped slightly.
replace fan clutch. No help.
replace aux fan. No help.
replace both temp sensors with dealer parts. No help.
replace old crusty ccv valves. No help.
replace many rad caps.
flush and burp the **** out of the coolant again. No help.
replaced t stat w dealer 195, dealer water pump, and replaced the mopar hd cooling radiator in there from PO with mishimoto aluminum. Now sits at 210 like a rock in SoCal summer. On desert climbs in 4x4 it will rise a bit. 220 is ok. On obdii it’s even cooler since the temp sensor for the computer is at the front of the engine. In fact, once it hits around 210-12 at the gauge, the temp will actually fall slightly back down, even at idle. That’s the t stat opening up more, and the cooler water rushing in.
I have a stock mopar trans cooler that was part of the towing package.
Before this odyssey I would regularly hit 223 at idle or higher. Once I hit 235 on a climb and decided that was it time to pull the rad, pump and tstat. Never had an issue since and I’m running the xj clutch. Now on long climbs I can hit 220 or so but I’m talking 7k feet of climbing nonstop at low rpms, on unpaved hardpack and washboard with my tires at 12-15psi
Last edited by msumms; Jan 27, 2019 at 10:35 PM.
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CF Veteran
Joined: Sep 2009
Posts: 8,567
Likes: 20
From: ☼ Blackhole Sun
Year: My Jeep is a GMC
Temperatures verified with an IR heat gun?
Is the cooling system contaminated with any type of "stop leak" substance?
Perform a compression and/or leak down test.
Anything thing other than OEM style cheapie radiator is not necessary. A thermostat is necessary to restrict flow through the cooling system for maximum heat dissipation.
Is the cooling system contaminated with any type of "stop leak" substance?
Perform a compression and/or leak down test.
Anything thing other than OEM style cheapie radiator is not necessary. A thermostat is necessary to restrict flow through the cooling system for maximum heat dissipation.
CF Veteran
Joined: Oct 2018
Posts: 1,096
Likes: 166
From: Hunt County Texas
Year: 1995
Model: Cherokee (XJ)
Engine: 4.0L
Yes it does, well maybe sit is the wrong word. But, As stated above the thermostat gives the system a restriction that slows coolant flow down and allows the coolant to bleed off more heat though the radiator before cycling back to the block/head.
I've wheeled in the socal desert during the summer time and in Texas when temps were over 110 with a fully stock cooling system. If the system is working properly and you don't have a headgasket leak or a badly worn timing chain the stock system works just fine.
I've wheeled in the socal desert during the summer time and in Texas when temps were over 110 with a fully stock cooling system. If the system is working properly and you don't have a headgasket leak or a badly worn timing chain the stock system works just fine.
Seasoned Member
Joined: Oct 2017
Posts: 325
Likes: 15
From: NW OH
Year: 1991
Model: Cherokee (XJ)
Engine: 4.0L L6 OHV 12V
I wonder how much difference a transmission cooler makes? Msumms mentioned earlier in this thread that he has the Mopar tow package factory cooler installed.
Last edited by Rlmx; Jan 28, 2019 at 04:05 AM.
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