Need help bad with XJ overheating problem...out of ideas!!

[expeditionxj]

So I purchased a 2000 XJ last year for cheap but it had a oil pressure issue which seems to have been caused by a 0331 cracked head. I purchased a remanufactured engine and replaced to motor last October.

Since then I have been battling a overheat problem any time the engine is under a load, going up a slight hill, on the trail, towing our tent trailer. It will rise to 230-240 like its nothing, one time the gauge spiked to 260 on a trail. Here are the facts of what i've tried. Happens at all ambient temperatures, I do live at 7,000 feet.

High temps have been confirmed with an infrared thermometer, however temps seem to be all over the place when thermometer is pointed at thermostat housing, up and down depending where you point it on the housing

1. 2 row aluminum radiator
3. Flowkooler water pump
3. Multiple new thermostats, now has a Robert Shaw 195 that is confirmed working
4. ZJ HD fan clutch
5. E-fan wire to switch, keep temp down around town but does nothing when under load
6. NEw A/C condensor, old one looked like it could be blocking flow but new one made no difference
7. Compression test was normal, 155-160 across all cylinders
8. Combustion leak test fluid did not turn yellow like is shown when there is a leak, however there was a VERY slight change in the blue fluid to a bluish green ??
9. Replaced Pre-Cats
10. Spring in bottom hose
11. Removed transmission cooler lines from radiator and installed separate cooler
12. Radiator cap, has OEM cap on it and hoses are pressurized while running

Im sure there is more. I am tired of throwing money at this thing trying to fix a mystery problem. I dont feel comfortable even driving it off the mountain anymore so it goes to work with the wife and thats it.

Please help! I want to drive this thing off a cliff!!

Thanks,

Daniel

 

[Jim K in PA]

Radiator cap? Trust me, it's been overlooked after all the stuff you mentioned before.

 

[expeditionxj]

Been replaced just forgot to add to the list. Has been replaced a few times, now had an OEM cap on it and it does hold pressure

 

[jeep-N-montero]

No oil in the coolant and no coolant in the oil? Properly bled the air out of the system? Brand and flow pattern of the radiator?

 

[expeditionxj]

No oil in the coolant and no coolant in the oil? Properly bled the air out of the system? Brand and flow pattern of the radiator?

No cross contamination apparent either way. The air gets out of the system after a couple drives normally, the thermostat has the air bleed hole in them to help with that.

The radiator thats in it now is a 2-row Champion all aluminum, made no difference from a brand new stock unit. I believe they have 2 - 3/4" wide rows

Thanks for the ideas guys, im thinking of just pulling the head and seeing if there is a small combustion leak that causing the high temps...bad idea?

 

[bob91yj]

Is the serp belt routed correctly? Are you sure it's the correct water pump? I forget what years it was but there are clockwise and counter clockwise water pumps for the 4.0L, if I remember right it's the YJ's that have the bastard pump, but verify that. If your engine is from a different year/application that may be the culprit. Have you verified temps at the radiator inlet/outlet to see that there is flow through the radiator?

 

[expeditionxj]

Is the serp belt routed correctly? Are you sure it's the correct water pump? I forget what years it was but there are clockwise and counter clockwise water pumps for the 4.0L, if I remember right it's the YJ's that have the bastard pump, but verify that. If your engine is from a different year/application that may be the culprit. Have you verified temps at the radiator inlet/outlet to see that there is flow through the radiator?

Yes the belt routing has been verified, have put in 2 different water pumps both counterclockwise rotation which is correct for the xj. Flow through radiator seems good, temp drops about 30 degrees through radiator.

 

[docwatson]

Maybe your coolant is moving to quickly with the increased flow which isn't allow effective heat transfer? If that is the case adding a restrictor will help. Here is a how-to if you are interested and an article with some decent info on cooling systems.

http://jeep-xj.info/HowtoRadiatorRestrictor.htm

http://www.circletrack.com/enginetech/ctrp_0910_critical_engine_cooling_technology/viewall.html

Maybe adjust your coolant/water ratio? A high antifreeze to water ratio cools less effectively then a 50/50 mix or better yet a 40/60 mix

 

[bad luck]

overheating

I think the problem is the Champion radiator. I will refer you to a website called Offroad Passport, And look up a thread called Clifford. They went through all the things that you are. But they finally solved it with an oem radiator. I suggested this to a guy on another forum, who has been having all those same issues and he too tried an oem radiator and it solved his overheating problem. At least go and read the thread about Clifford, I think that might convince you to give it a try. Good Luck

 

[Mekcanix]

I think the problem is the Champion radiator. I will refer you to a website called Offroad Passport, And look up a thread called Clifford. They went through all the things that you are. But they finally solved it with an oem radiator. I suggested this to a guy on another forum, who has been having all those same issues and he too tried an oem radiator and it solved his overheating problem. At least go and read the thread about Clifford, I think that might convince you to give it a try. Good Luck

I was going to suggest the very same thing

 

[UK4X4]

One thing to check after mixing parts...


that the fan your using is pulling air through the rad and not pushing - ie the blades are the right way arround for the rotation of the pully.

That cost me a head gasket a long time ago:snorkel:



I'd pull the thermostat for now too so that you get free flowing water

 

[ThatCherokeeGuy]

The biggest contribution to xj over heating is the overall hood design. There's hardly any room between the top of the engine and the hood, so air can't circulate, which results in all the heat getting trapped in around the engine. Look into a louvered hood insert, I've talked to a lot of xj owners and this is one true way of eliminating overheating issues. Take a look at Hyline Offroad, they have a louvered kit that boast keeping the engine 10-20 degrees cooler on the trail and street.

http://www.hylineoffroad.com/product_info.php?products_id=54

 

[expeditionxj]

I think the problem is the Champion radiator. I will refer you to a website called Offroad Passport, And look up a thread called Clifford. They went through all the things that you are. But they finally solved it with an oem radiator. I suggested this to a guy on another forum, who has been having all those same issues and he too tried an oem radiator and it solved his overheating problem. At least go and read the thread about Clifford, I think that might convince you to give it a try. Good Luck

Thanks. That thread is a good read since I am battling the same issue

 

[expeditionxj]

The biggest contribution to xj over heating is the overall hood design. There's hardly any room between the top of the engine and the hood, so air can't circulate, which results in all the heat getting trapped in around the engine. Look into a louvered hood insert, I've talked to a lot of xj owners and this is one true way of eliminating overheating issues. Take a look at Hyline Offroad, they have a louvered kit that boast keeping the engine 10-20 degrees cooler on the trail and street.

http://www.hylineoffroad.com/product_info.php?products_id=54

I installed hood vents last month and it made no difference

 

[expeditionxj]

One thing to check after mixing parts...


that the fan your using is pulling air through the rad and not pushing - ie the blades are the right way arround for the rotation of the pully.

That cost me a head gasket a long time ago:snorkel:



I'd pull the thermostat for now too so that you get free flowing water

Fans are stock mechanical and stock efan at this time because all electric made no difference. Definitely pulling air the right way.

Thanks for the ideas guys