OVERHEATING PROBLEMS

My XJ is overheating in traffic or at a stand still with the ac on or off. The electric fan is working. The waterpump, thermostat, collant temp sensor (on the side of the engine), radiator, radiator cap, and fan clutch are brand new and at this point I am dumbfounded on why this is happening. It does fine driving down the road though. I will say this is that the fan will not come on at 220 it only comes on when i turn the ac on.

whats next a new electric fan?

95xj, 210K miles
4.0l, d30/35, np231, aw4

Three things that might help:

1. Double check you put in the right thermostat

- Make sure you installed a 195'F one, and that it a quality brand. The :firedevil el cheap0 thermostats :firedevil are normally the guilty party of XJ cooling system issues.

2. Is the engine block covered with caked dirt/grease/oil?

- A clean engine block runs much cooler.

3. If the Radiator is salvaged/refurbished then Flush it, or even better Reverse-Flush the entire cooling system.

http://answers.yahoo.com/question/index?qid=20071007165154AA7Qz5k

- If the core tubes are filled with debris that can build up it could be one thing that is taxing your cooling system while the Jeep is standing still.

For searchers--
Scroll to bottom of this page for 'SIMILAR THREADS'.
------------------------------------------------------------------


3)---Fan clutch Replace with the N.A.P.A. GC HD fan clutch P/N in threads below.

4)---New thermostat - Mopar O.E.M 195*F
OR Stant superstant 195*F

1)---Check radiator for clogged air flow and coolant flow-clear or replace.

2)---remove 'stat and test run .


Good Luck,
Orange

Ok first you say the fan works... Then you say it doesn't come on at 220 but will come on with the a/c. So there is your issue. It is in the coolant temp( for the fan not the computer) sensor, wiring, relay, or fuse as the fan as you stated works. Do you have the sensor on the thermostat housing to as well as the one on the block. If you do the one on the block is usually for the comouter and the one on the thermostat housing is for the fan.

orange said:

For searchers--
Scroll to bottom of this page for 'SIMILAR THREADS'.
------------------------------------------------------------------


3)---Fan clutch Replace with the N.A.P.A. GC HD fan clutch P/N in threads below.

4)---New thermostat - Mopar O.E.M 195*F
OR Stant superstant 195*F

1)---Check radiator for clogged air flow and coolant flow-clear or replace.

2)---remove 'stat and test run .


Good Luck,
Orange

Click to expand...

Actually, you do not want the HD clutch as it does not fit...

What you want is the without max cooling fan clutch:

Part Number: TEM 272310
Product Line: NAPA Temp


Attributes:
Fan Clutch Bolt Circle Diameter : 1.39"
Fan Clutch Fan Mount Diameter : 2.62"
Fan Clutch Fan Mount Height : 2.25" <<Critical Dimension>>
Fan Clutch Height : 3.24" <<Also rather important>>
Fan Clutch Overall Diameter : 7.23"
Fan Clutch Pilot Diameter : .63"
Fan Clutch Rotation : Counterclockwise
Fan Clutch Style : 7" Heavy Duty
Fan Clutch Type : Thermal

The comments inside the <<>> are mine to clarify why this clutch.


I ran this on my 98 until I replaced the whole lot with a Davies-Craig EWP115 Electric Water Pump setup. I replaced the Jeep mechanical fan with an 8c607 series 2-speed Ford fan out of a late model Taurus. I also modified the wiring on the Jeep Aux Fan so that it will run either when the PCM calls (AC or 218F) for fan or when the Davies-Craig controller calls for fan. My temps run between 191F and 201F with the AC off and a rock solid 191F with the AC on. I account for the stable AC on temp due to the Aux fan running. The Ford fan runs on low speed as long as the ignition is on.

Thank you - o-gauge-steamer!

----NAPA 272310 is the number.----

---Accept no substitutes!!!

see, i just changed my radiator fluid because it was sitting right above 210 in traffic and it was fine. clean for weeks. i went wheeling and now its running a little hot again and my fluid is disgusting. i have no idea how it got contaminated though.

Has anyone tried the Flex-A-Lite Non Thermal Fan Clutch? I was checking Summit and came across it:
http://www.summitracing.com/parts/FLX-5257/

This Flex-a-lite Non-Thermal fan clutch is fully engaged at low rpm's, turning the fan at full water pump pulley speed. As rpms increase, the clutch permits fan rotation to slip, lowering fan rpms and engine drag at higher engines speeds. Rotates fan at a constant 60% of water pump pulley speed to reduce fan drag.

robswampthing said:

see, i just changed my radiator fluid because it was sitting right above 210 in traffic and it was fine. clean for weeks. i went wheeling and now its running a little hot again and my fluid is disgusting. i have no idea how it got contaminated though.

Click to expand...

use a cooling system cleaner in your system after a good flush. follow the directions on the bottle. may need to do it more than once. and when you refill with new coolant, either use premixed, and use coolant and DISTILLED water.

not trying to highjack, but i did do a clean flush. my fluid was clean for weeks. it wasnt until i went wheeling that it got messy. i just cant figure out where the mud is getting into my cooling system from

Dirt has free access into the CRT, Coolant Reservoir Tank thru the open vent. Take about a 1 inch cube of foam rubber, test you can blow air thru it, then stuff it into the CRT vent. Also find about a 3 inch diameter 'bout 1/8 thick and put it over the fill opening and close the cap on it. This should keep out the dirt, hopefully.

Mixing different types of coolant will create a "mud" or sludge and will clog your cooling system causing overheating.

I would look at testing for a blown head gasket, if the coolant is turning to sludge quickly it could be oil mixing into it.

I had the head off my '92 4.0 eight years ago to replace the lifters. What I found while cleaning things up was the rear-most coolant passage in the head was almost completely clogged with coked-up coolant. Mostly in the head, a little in the block. I chipped it out, vacuumed it the best I could, and all is well. It had never overheated, but since, it has always run in the lower ranges of normal. Just a thought....

thanks for input everyone im going to go wheeling again tommorow. after that im going to clean it again and try these idea's