Who needs higher flow in racing? When you race the higher engine rpms already deliver higher flow rates and your radiator can only pass a finite volume.

Hi Flow pumps tend to work better at lower speeds e.g. rock crawling and towing.

 

Offroadinca is right about the high flo waterpump it is great for lower rpms get the napa pump it a new one not a reman pump also this part # at napa for the heavy duty fan clucth 272310 I beleive.

 

180 vs 195.
As was stated before the termostat only controls the lowend of the operating tempature. The Clutch fan could be bad. It should have resistance to it not free wheel like on a bearing.

Remember the old 351 Cleveland 4 barrel engines. They would heat up if you tossed in a normal thermostat. They required a HI-Flo thermostat.

These thermostats actually open with a twisting vane and flow alot more coolant.

I would suggest the 180. In a highflow Thermostat. Then add some water wetter.

Water Wetter breaksdown the natural tendency of water to bead up. So the water will stick to the surfaces inside the engine and pull more heat out of the engine.

 

FWIW,
I tried Water Wetter in my 4.6L stroker, no measureable difference at all.

 

My Flowkooler knocked the temperature right down - problem solved. I read they throw so much water they can collapse a weak spongy hose.

Did they collapse?

 

Just purchased a clean, stock, one owner 1999 4.0 cherokee and I have been searching posts as I go through it with a pro active service check.
It's running at 190* - 200*, in slow traffic it inches up to 210 here in Tampa's hot climate.
What is the norm for these?
Also I cant find the fuel tank capacity in the manuel?
Thank you in advance.

 

The Xj's are designed to run at 210 degrees. That is their optimal operating temp. Your fuel tank should be 19 gallons if im not mistaken. Welcome to the cherokee family. Hope your ready for the "bug"! Good Luck!!

 

x2

 

I followed another thread the other day on cooling - somebody's car would not get warm.

So I watched my temp gauge this morning. I started the engine, gave it, ohhh, ten seconds to "warm up" (it was 30 degrees out...), then idled down my 700 driveway and eased out on the road. Within 1/4 mile, it was registering heat on the guage (easy on the gas, maybe 40 MPH). At the one mile mark, I increased to 60 MPH. Within three miles my engine temp gauge read 215 degrees and I watched as the t-stat opened and the temp fell to 195 and sat there for the next ten miles. It then eased up to 210 and stayed there...just like it is supposed to.

Stock 195 t-stat. New Advanced Auto radiator (the $109 one). 210,000 miles on the clock. Nothing else special.

The t-stat is doing exactly what it is supposed to do. All arguments aside, if the cooling system is functioning properly, you should see 210 degrees on the dial...winter, summer, spring and fall...when the engine is fully at "operating temp".

Now, as for the towing situation: 2800 pounds is almost double the load the XJ encounters normally. That is not insignificant. XJs are not tow trucks and, IMO, you're at the limit of what it can handle. And I think VA is full of hills, is it not? That's a lot of burden, really, especially with the AC on. IMHO, you're right on the ragged edge...I'd prepare for trouble if this kind of service will be routine.

 

Old thread comes back to life so heres a little info on a recently conducted test (curiosity) on our '98 XJ, OBD-II.

Unplugged the coolant sensor connector at the t-stat housing and started engine. ScanGauge displays -40F coolant temp (default signal from ECU I presume), system in open loop and efan runs constant (compressor not engaged). After approx 45 seconds, system enters closed loop (ScanGauge), still displays -40F coolant temp and efan still running. With engine still running, plug coolant sensor in, efan stops, coolant temp displays 83F and system is still in closed loop. Engine runs the same as always - perfect. Apparently coolant temp has little effect on engine performance even when well below normal operating temp. These are the facts, YRMV.

 

Interesting test but it proves nothing (read franz's earlier post) when you unplug the coolant sensor the pcm runs the engine as best it can on a predetermined engine management "plan" to keep it as clean and efficent as it can i.e. as close to 14.7:1 as it can get. As far as your o2 sensors, downstream o2's don't come into play untill closed loop op, the only thing the pcm does on startup is turn on the o2 heaters and monitor the o2 to see if it is operating correctly.

 

That test is flawed, as mentioned above. I had a bad CTS on my 96 that was ohming out at like -40 degrees. The XJ was an absolute nightmare to start and it barely idled. The CTS was only a month old so it was pretty much the absolute last thing that I checked. When I finally got to it, unplugging it made the jeep run and start fine. Prior to that, it was running so bad it stalled on the side of the road and wouldn't restart. Without any other changes, I replaced the CTS and it's run flawless since.

-E

 

I have an 1800lb trailer that I tow all the time. Last summer I had the entire family (wife, 2 kids, 2 dogs), trailer fully loaded, with a canoe on the roof, and the XJ towed them through the pocono mountians in 95 degree weather with no trouble. Temp didnt get above 212 on the dash

Go back to the 195 t-stat, check your clutch fan, make sure the rad is working correctly.

with your new radiator, the only way it would run so hot is if something isnt working correctly. You shouldnt have to upgrade to better fans, put hood vents in, or anything like that

Chuck

 

I am not sure if anybody already asked this but is your electric fan kicking on when the temperature gets that hot? Nevermind didn't ready your entire post.

 

The upstream O2 is the sensor that provides the ECU with rich/lean info so the injector pulse can be correctly calculated in order to achieve 14.7:1 a/f ratio. The "loop closes" when the upstream O2 reaches it's operating temp and begins sending info to the ECU......seconds after the engine starts and well before normal coolant temp is reached.