I've got a problem and I hoping to find a solution. Any help would be greatly appreciated.
1996 jeep cherokee 4.0 w/ 60,000 original miles / auto, running 225/75 tires, all stock. Towing a Trail-lite Bantam travel trailer weighing in at about 2800 lbs.
I read a lot on this forum and tried to be proactive to head off any problems. First, I upgraded my radiator from a 1" radiator to a 3 row 2" all
copper.
Second, I installed a FlowKooler water pump from Quadratec (high flow)
Third, Installed a 5000 lb towing transmission cooler.
Forth, Installed new serpentine belt.
Fith, cleaned the condenser coil for A/C.
Sixth, Installed a new stant 180 degree thermostat.

Here's the deal took camper for a test run the other day, Running the A/C like I would with family anyway. It did fairly good but during a long tow uphill the temp got up to between 210 and 240 deg and it didn't come down until I got home about 15 minutes later. Even sitting still it would not come down for a while. Both fans were running and after sitting for
awhile it finally started coming down. I thought with the larger radiator and all I wouldn't have any problems with heat, but I just don't know.
I plan on replacing the fan clutch. Other than that I need some help or
advise. Thanks for any help.

Duane in VA

 

Where's you get the radiator from?

I've read that the FlowKooler water pumps aren't all they are cracked up to be, but I don't have any first hand experience with them.

What gear are you towing in?

 

Try getting rid of the 180 degree tstat first of all and run the right one 195, 4.0 wont run right with any other tstat only 195.

 

I got the radiator from "Radiator Express"

Towing in '3' not overdrive.

 

I am planning on replacing it with 195.

 

I've never been a big fan of high flow water pumps for street use. They're more intended for use in race applications with BIG radiators. The coolant needs to spend a certain amount of time in the radiator to allow heat transfer. Rush it through too fast, not enough heat transfers.

I had a Chevy truck with a built 350 that cooled fine with the stock pump but when the pump started leaking I just had to put a high flow pump on. Bigger's always better right? Long story short I had overheating problems, new radiator, new t-stat, no t-stat, smaller (overdrive) pump pulley (must not be getting enough flow, so turn it faster!) nothing worked! Racing friend of mine told me to go back to stock pump and pulley. No more overheating. He came over and showed me, with an infrared thermometer, how much heat transfer I was getting across the radiator by measuring the tank temp at the upper hose and then at the lower hose. If I remember right I think the temp differential was 20 deg~ with the high flow pump and around 40-50 with the stock pump.

I can't say that this is a guaranteed fix for your rig but something to think about. If you still got the stock pump, might be worth putting it back on for a try. At least they're fairly easy to change.

Jim

 

Also, check your fan clutch. Just because you see the mechanical fan spinning doesn't always mean it is engaging as it should; it could just be free spinning. Just let your rig reach operating temp, then turn off the Jeep. Pop the hood and try to spin your mechanical fan; it should have resistance and not spin very much. Also, x2 on the stock pump vs high flow pump debate. If you think about it, a stock pump is going to flow at a standard rate in a 1 row rad, however if you upgraded to a 3 row, the same rate of flow is going to reduce by a factor or 3, meaning the coolant flows slower through the rad. This allows more time for the fans to blow off heat. If your running a high flow pump, your just going to have standard heat transfer. If you change back to a stock pump (just my opinion, NAPA has a lifetime warranty one that I got, I think its great) and it still overheats, consider upgrading the fans. You could go all electric like many are doing, or do what I did. I upgraded my single electric fan with a higher cfm one, then upgraded my mechanical fan with a newer design that pulls more air. Good luck on finding your problem. I feel your pain; almost pulled my hair out when my XJ had overheating issues lol.

 

x2 one the tstat 195 is best if 180 was better they would have fitted them at factory lots of poeple run 180 stats but they are wrong also check the fan clutch

 

I think the first couple of things I'm going to do is replace fan clutch and
then try and get all the air out of system. And maybe replace thermostat to 195. Will see where this leads me. I'll post the results. Thanks for all and any more help.

 

Running a 195F vs 180F t-stat is going to have zero effect on coolant temps reaching 240F. The t-stat only controls MINIMUM coolant temp. A '96 XJ is OBD-II which enters "closed loop" and operates lean/clean within seconds of engine start-up due mainly to heated O2 sensor(s), not coolant temp.

 

180 stat will be open more not allowing the rad to cool as affectivly

 

DJB383 go lay down in the corner and quit giving info on cooling systems cause on all your posts you show you know nothing,quit giving bad info.

 

I don't think those temps are unusual for uphill towing during the summer. If you switch the fan clutch, use the ZJ one.

-E

 

Ummmmmm....Wrong.
OBD2 PCM's do not moniter the O2 sensors until the the engine reaches normal operating temp. This is monitered by the PCM via the Coolant Temperature Sensor. Once the proper temperature is achieved ( and it takes more than a few seconds) the PCM switches from Open Loop to Closed Loop.

An engine that does not reach normal operating temp due to a colder stat will suffer from poor performance and terrible gas mileage.

 

This could be a stupid question but have you flushed your cooling system? I know you changed your radiator and pump but are the motor passages clean?

You should probably change your Tstat back to stock.

How about upgrading your fan? Maybe do a duel electric fan conversion?