I have a 99 jeep Cherokee 4.0 and it gets very hot often. i have 3 elect fans in it (2 that suck in, 1 that blows through). i do not run a thermostat for max water flow, i added a new radiator (The Heat Buster or so it said), i also removed skid plate under front to allow more air flow. i placed 2 intake air vents on top of hood mounted backwards to allow heat to be pulled out of engine compartment (heat rises). yet it stills runs hot. this problem has been on going and getting worse. it started sometime after i replaced the Crank Shaft Position Censor (old one went bad). the jeep runs just fine (no rough idle, no shaking, no power loss). only thing else i can say is the miles per gallon has changed. it eats a bit more gas then it did before. I am going to change the Crank Position Censor just to be on the safe side. would that be the reason for the heat issue????? any other ideas?????

 

Have you checked the actual coolant temp? May just be the temperature sensor is off.

 

it is a little off but it does over heat. temp rises to 215 holds then jumps up in red, shortly there after if i do not stop it will overheat engine.

 

Have you checked to see if your water pump is actually moving all that nice, cool fluid?

 

when my jeep started to warm up almost to the point of boiling water,got home and cleaned the radiator added water and bought a new thermostat and solved my hot temperature issue hope this might be of any help to your problem.Another thing is that extreme heat might have caused some rods to warp which happened to a buddy of mine.

 

Thought about that 2 months ago, looked it over it is in good working order....

 

Tough to say without actually trouble shooting it, but with these XJ's it seems like it is usually the fans not coming on, the water pump not pumping enough, or the thermostat. You have no thermostat in, say it pumps enough water, and the fans are working properly. Hmmmm.

If there is sufficient flow throughout the entire system, I would start looking at head gasket issues? If the coolant has a "milkiness" to it, it can mean that the head gasket isn't doing its job and allowing the fluid to become contaminated. If the fluid is moving the way it's supposed to, and being cooled the way it's supposed to, then it has to be heated in a way it's not supposed to. Happy hunting, because at this point, it's all troubleshooting.

 

i have not looked at head gasket yet but was getting ready to as a friend asked yesterday about it. thank you so very much for you time and ideas!

 

you need to run a thermostat!!!! they make high flow thermostats. But you will have more heating issues not running a thermo stat than if you do.


you need to look over theses items:

clutch fan in good working order
water pump flowing enough
electric fan coming on when it should
radiator not clogged(very common problem)
coolant in good condition/color
no air in the system. (with an open system leave the rad cap off, run the heater at full blast with the engine running add coolant/water as needed



If any one of those is off you need to trouble shoot that part.

you need to run a 193* thermostat tho. They even make high flowing ones

 

Just because the water pump looks to be spining from the outside doesnt mean that it hasnt disintegrated the impeller and in turn not pushing the water thru the block and radiator. I have only seen this happen once on a 4.0L and it made no noise to indicated that it went bad.

 

Sometimes people with high flow water pumps say that the coolant doesn't have enough time in the radiator to properly cool without a thermostat in place. It is not very likely that this is true. Many an article can be found on the topic and seem to come to the same conclusion: It only takes longer to warm up (especially when it's cold out). If it doesn't have as much time to cool in the radiator, it doesn't have as much time to heat in the motor. Ya dig? Leaving the thermostat out is not the cause of overheating. In fact, it probably gives it a bit more drive time before it overheats.

 

I just picked up a new water pump and will put it in to see if that is the issue. will let everyone know in a few weeks if the problem is solved. Weather calls for over 90 all week so ill see how she does. "THANK YOU" to all who had input on this issue!!!!

 

If a new pump doesn't solve the problem, I'd suspect the aftermarket efans as the culprit. Also, efans place extra load on the alternator, which places extra load on the engine, which could cause lower mpg.

 

It would be funny as hell if all this time, the fan in the front that was supposed to push it in was actually working in reverse. Oh, the irony of it all. LOL

 

Dayum! U r good but for the OP's sake, lets hope u r not that good. LOL