XJ Running Hot Multiple Coolant System Upgrades

[AzBeeKing]

I have recently built a 1993 XJ with 169k miles. 6.5 inch long arm, 35" tires, 4.88 gears, lockers f/r. I also add a CCS 3 Core Radiator, Hesco Hiflow water pump, Hesco Hiflow thermostat housing, new oem thermostat, replaced all radiator hoses, New fan shroud and electric fan. Its running over 210 while on the freeway with the ac on high and slightly over still when not running the ac. It runs slightly over 210 while idling with ac on. It runs right at 210 when idling with no ac. It gets hotter and cycles back down when slowing down after running at freeway speeds.

I do have the heater core bypassed.

This concerns me because the weather is still in the high 70s here in phoenix but I know the hotter temps are coming. I want to be able to idle with the ac on and not worry about it.

I know the water jackets are clear because we flushed them very carefully when changing water pump etc.

4.0, 4x4, 8.8 rear, d30 front

Any thoughts?

Thanks
Kendall

 

[hayhaulerleradoxj]

One of the high mileage coolants might help! I use Valvoline, and if your using a cheap oil that will get it hot..... Valvoline synthetic is good for those old motors.

 

[AzBeeKing]

Thanks I'll make those changes today.

Any other thoughts or experiences?

 

[ParadiseXJ]

For idling in traffic...and traveling at freeway speeds...your next upgrade should be to get a HD ZJ fan clutch. It's a NAPA part and NOT the MAX COOL version (the MAX won't fit). It increases the air flow considerably. I have the part # at home and I'll send it along when I get there unless someone else chimes in with it.

 

[notamos]

For idling in traffic...and traveling at freeway speeds...your next upgrade should be to get a HD ZJ fan clutch. It's a NAPA part and NOT the MAX COOL version (the MAX won't fit). It increases the air flow considerably. I have the part # at home and I'll send it along when I get there unless someone else chimes in with it.

Ditto. I've run this clutch for a few years now & it is excellent. It sounds like my XJ is going to take off @ times but it does keep that fan moving.

ETA: Napa 272310. I've always heard it turns 80% of the time compared to 30% for the OEM fan.

 

[mtbxj87]

x3 on the zj clutch. Im not sure if the zj fan clutch will work for bigger radiators, its already a tight fit on stock stuff. there was a thread somewhere on naxja about hi flow water pumps and bigger radiators flowing too fast and not cooling off the fluid before cycles back to the engine.

 

[Tim_MN]

The oil type used has no effect on the coolant temperatures.

I too have heard the story about high flow water pumps not cooling off the fluid before cycles back to the engine. I have no idea if it is true.

You should first confirm the actual coolant temperatures with a live data OBD code reader.

 

[sidriptide]

did you make these changes to your cooling system because there was a problem? or strictly as a preventive measure?
sometimes "upgrades" are a waste of money.. XJs run hot.. it's what they do. stock parts are often the best way to go, unless you are re-engineering the system and get involved with the airflow and coolant flow characteristics like some of the guys here have done.

 

[PaulJ]

What kind of electric fan did you install? It's probably not moving enough air.

 

[lazyxj]

You should first confirm the actual coolant temperatures with a live data OBD code reader.

Try checking the actual coolant temperature by using an infrared thermometer to read the thermostat housing temperature and then
compare it to either the dash temp gauge or better, a digital gauge that reads off the OBDII Bus.
http://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-69465-8905.html
I have found many temperature sensors are out of calibration and read too high or low, usually higher than the actual temperature.
Mopar sensors seem overall to be better calibrated than aftermarket sensors.

I use a ScanGuage to monitor the OBDII Bus's various sensors.
http://www.scangauge.com/products/scangaugeii/

 

[IslanderOffRoad]

Ever check your catalytic converter? Mine was clogged and giving similar overheating symptoms under load

 

[iwannadie]

Those temps don't really sound that bad to me. I have most of the same upgrades and run around the same temps in Az. I do have the ZJ fan clutch though and feel that is totally worth it and it pushes a lot more air. I also have a trans aux cooler.

210-215 I'm not worried about as long as it drops back down. I tend to heat up while sitting in traffic but cool down once I get moving.

When you replaced the radiator did you blow any debris out of the AC condenser from behind, lots of junk can get clogged and restrict air flow. New radiator cap?

You should also confirm those temps with an IR gun or replace the temp sending unit, never know how accurate those readings really are. No reason to pursue a cooling issue without knowing the true temps. Then consider a transmission cooler to help keep those temps down too.

 

[AzBeeKing]

Thanks for all the replies. I made the changes because it was getting hot and figured the last thing I wanted was an overheat on the trail. The zj fan clutch is now happening. I'm also going to test the coolant temp with an ir thermometer.

I did not clean the consender I should have but now I don't want to blow debris into the radiator when cleaning it.

New cat converter done too

Thanks again love all the suggestions.

 

[huskyhauler]

I think cooling and brakes are the two things Xjs lack from stock. Still worth it though, let us know how you come out....

 

[Overland]

Mine would do that when it needed freeze plugs. Didn't see the leak for a while. Went as far as I could without pouring something stupid in it before pulling the engine out.

Your electric fan is running with the AC on, right? Why is the heater bypassed? Switching to heat and rolling the windows down brought my temperature down without having to stop, much less dump a bunch of expensive coolant on the side of the highway.

After replacing ALL of the freeze plugs, water pump, thermostat, control valve, and radiator, I finally caught the problem, it was a defective cap flange. I had even fabricated six little nozzles, zip tied them into the grille, and tied them into the washer bottle so I could soak it down on the move. Overloaded, pulling an overloaded U-Haul, I made it about five miles up US82 before the cap flange problem became evident. Another five miles or so with a new cap and more coolant. Pulled the wipers and stopped ever so often to fill the bottle, holding the pump on up every grade from Alamo to Artesia, where I replaced the radiator under warranty. It was relieving pressure to the reservoir so I had never seen the leak. Under extreme load, it would just gush around the cap.

Now I'm overloaded on 33s with 3:55s doing 75 with the AC on high. Also has a trans cooler. Gauge never comes near 210, and we've been in the 90s here recently. Same cheap Autozone radiator for the last two years.