Over heating problem

[NothingINC]

Just wanted to see if anyone has had similar problems and what might be the cause. its a 2004 TJ 4.0L
The last couple days by the time I get to work my coolant is over flowing and boiling in the reservoir and pissing all over the inside of the hood and on everything, i have replaced the thermostat and radiator cap and its still doing it. The temperature guage on instrument panel is only reading slightly above 210 but the inside of my hood and engine is covered in colant from it boiling out of the resevoir, It has only done it during the day the last 3 days, The 1st day I put in a new thermostat and radiator cap but it is still doing it.
The fluid seems to be circulating as when I pour in just water and run it i then see the res coolant mixing.
There is no smoke or anything like that and the temperature gauge is reading normal.
Any Ideas?
Thanks

[HuLuD44]

How is ure fan? May be a bad fan clutch. Also check ure water pump pulley.

[Goonies.nsd]

Yup fan clutch and may be water pump fins have rotted off. But this heat is pushing alot of cars over the edge. If you running A/C it can overload the radiator. The heat from the condenser wont let the radiator shed heat. Also make sure the radiator fins are clean. No mud or dust. Hard to diagnose overheating on Jeeps. they all do it at least once. My ZJ was running hot if i ran the A/C yesterday. Old truck and crazy heat where a little to much. Im propabaly going to do a fan clutch just to be safe and see if an extra electric fan could be fitted in front under the grill.

[Bandit1]

I will be sending down, John, a clutch fan and eletric one that if Bill dont claim, he can have if they fit.

NothingINC, dont go buying fans just yet. Lets see if bill takes the ones I am sending down to the island first.

[NothingINC]

ok, thank you, I have not had the AC on at all. I've had the top and doors off, so now that it pored I have a jeep filled with water. I was also told that the radiator could be clogged, would that cause the coolant to boil over in the reservoir?
Driving home at night its fine but on the way to work after about 25 minutes on the highway its starts to boil over and I notice fluid on my rock slider rails. then when i get to work and pop the hood I can see it boiling in the reservoir and the inside hood is coated with antifreeze. If it was the water pump would the fluid be mixing? When I put just water in and let it run and look at fluid with the radiator cap off it appears to have mixed with the coolant that was in there which leads me to believe it is circulating. I had my brother use a pressure tool to check and its holding pressure so I believe the hoses and lines are all good.

[Bandit1]

this sounds like the water pump to me. I had simular symptoms when I first got my XJ, and it turned out to be the water pump gone bad (fins rotted away). Put a new one in and no more overheating till the stock rad blew a gasket, then it was an upgrade to a 2 core all brass rad from AA.

[Goonies.nsd]

Yes if the fins rot off they will move some coolant but not enough to disipate heat. So if could be a pump. Second could be a radiator. If theres a clog in a few fins you will again not disipate the heat properly. Raditaor needs all the surface area you can get. Third could be the fan clutch (pretty sure the XJ and TJs are different). The clutch should be free when cool and with heat should tighten up. So see if the fan turns easily when cold and if its more resistance when hot you should be good there.

Other possiblities could be airflow to the radiator (winch, push bar, anything blocking the flow of air to the radiator. Im assuming the fan shroud is OK. If not that could be an issue. The fact that you say it doesnt seem to run hot by the gage temp could be a couple things. May not be overheating and the new cap is deffective. Would it be unusual for the first and second cap be bad?? Hell yeah but its a cheap triple check. See if you can borrow one just to triple check. AND if the cap WAS the problem there may be an air posket in the system. If there is the pump may be having issues pushing the air pocket out. Which will impede flow which will cause more overheating.

Lotsa possibilties only 1 answer.......maybe 2 gangin up on you LOL.

[flashbak]

Is it possible it was over filled and now it's ok check the hot cold line on the res..... Just putting it out there ....Is the water changing color and have u checked your oil level ....

[saharacon87]

Can you get your hands on a spill free funnel? If there are any air pockets in there it should get them out. X2 on the radiator cap as well. I usually start with the cheap stuff first and work my way up. If you do need to replace the water pump, do your self a favor and replace the thermostat as well.

[Bandit1]

I would buy a water pump and gasket, pull yours, if your water pumps is still good, then you have the gasket and you can return the pump, if not you have the pump too. Water pumps are not all that expensive especially for the 4.0.